Propulsion system for aircraft

Abstract

To provide a propulsion system for an aircraft that is able to restrict an increase in weight while mounting an auxiliary machine.SOLUTION: A propulsion system for an aircraft includes: a plurality of electric motors; a propeller having a plurality of blades capable of changing a pitch angle; a gear box that decelerates rotation of the plurality of electric motors and transmits the rotation to the propeller; an actuator that changes the pitch angle of the blades; a pump that is driven by power transmitted from the gear box and supplies oil to the gear box; a heat exchanger that cools the oil by using at least one of gas and liquid as a refrigerant; and a circulation passage along which the oil circulates between the gear box and the heat exchanger.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to aircraft propulsion systems. [Background technology]

[0002] Patent Document 1 discloses a propulsion system for an aircraft, which is driven by an electric motor powered by a battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent Publication No. 11420761 Summary of the Invention [Problem to be solved by the invention]

[0004] When an aircraft propulsion system uses an electric motor for propulsion, it is necessary to mount auxiliary equipment. In this type of propulsion system, it is desirable to suppress an increase in weight while mounting the auxiliary equipment.

[0005] Therefore, one aspect of the present disclosure aims to provide an aircraft propulsion system that can suppress weight increase while carrying auxiliary equipment. [Means for solving the problem]

[0006] An aircraft propulsion system according to one embodiment of the present disclosure includes a plurality of electric motors, a propeller having a plurality of blades whose pitch angle can be changed, a gearbox that reduces the rotation of the plurality of electric motors and transmits it to the propeller, an actuator that changes the pitch angle of the blades, a pump driven by power transmitted from the gearbox and supplying oil to the gearbox, a heat exchanger that cools the oil using at least one of a gas or liquid as a refrigerant, and a circulation path through which oil circulates between the gearbox and the heat exchanger. Effect of the Invention

[0007] According to one aspect of the present disclosure, it is possible to provide an aircraft propulsion system that can suppress weight increase even when accessories are mounted. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view of an aircraft equipped with a propulsion system according to a first embodiment. FIG. [Diagram 2] FIG. 2 is a block diagram of a propulsion system for the aircraft of FIG. 1. [Diagram 3] FIG. 3 is a perspective view of a configuration near a gear box in the propulsion system of FIG. 2. [Figure 4] FIG. 3 is a front view of the configuration near the gearbox in the propulsion system of FIG. 2. [Diagram 5] FIG. 3 is a rear view of the configuration near the gearbox in the propulsion system of FIG. 2. [Figure 6] FIG. 3 is a side view of the configuration near the gearbox in the propulsion system of FIG. 2. [Figure 7] FIG. 3 is a side cross-sectional view of a configuration in the vicinity of a gearbox in the propulsion system of FIG. 2. [Figure 8] FIG. 11 is a block diagram of an aircraft propulsion system according to a second embodiment. [Figure 9] FIG. 11 is a block diagram of an aircraft propulsion system according to a third embodiment. [Figure 10] FIG. 11 is a block diagram of an aircraft propulsion system according to a fourth embodiment. [Figure 11] FIG. 13 is a block diagram of an aircraft propulsion system according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. In the following description, "forward" means the side on which the propeller is arranged in the axial direction of the rotation shaft of the propeller of the propeller of the propulsion system, and "rearward" means the side opposite to the side on which the propeller is arranged in the axial direction of the rotation shaft of the propeller. In addition, the direction perpendicular to the axial direction of the rotation shaft of the propeller is referred to as the "radial direction" and is given the symbol R. "Side" means the radially outward side of the propulsion system.

[0010] First Embodiment FIG. 1 is a perspective view of an aircraft 1 equipped with a propulsion system 10A according to the first embodiment. The aircraft 1 is a propeller aircraft equipped with a plurality of propellers 11. The aircraft 1 has a body 2, a pair of left and right main wings 3, and a tail 4. The body 2 extends in the longitudinal direction. The pair of left and right main wings 3 are attached near the center of the body 2 in the longitudinal direction. The tail 4 is attached to the rear end of the body 2. The pair of left and right main wings 3 extend to the left and right, respectively. Two nacelles 5 are attached to the lower part of each main wing 3. The two nacelles 5 are arranged to be spaced apart in the lateral direction. A propulsion system 10A that generates thrust for the aircraft 1 is arranged in each nacelle 5.

[0011] The propulsion system 10A includes a propeller 11 and a drive unit 20 that drives the propeller 11. The propeller 11 has a hub 11a and a plurality of blades 11b supported by the hub 11a. The plurality of blades 11b extend from the hub 11a in a radial direction R. The propeller 11 is disposed in front of the nacelle 5. The drive unit 20 is disposed behind the propeller 11. The drive unit 20 is disposed within the nacelle 5.

[0012] (Overall configuration of the propulsion system) Fig. 2 is a block diagram of the propulsion system 10A of the aircraft 1 in Fig. 1. The drive unit 20 includes a plurality of electric motors 22 and a gearbox 23. The plurality of electric motors 22 are driven by power supplied from a battery 21 via a power line 25. The number of the plurality of electric motors 22 is, for example, four, but is not limited to this. The battery 21 is, for example, a fuel cell or a storage battery. The fuel cell generates power by an electrochemical reaction between hydrogen as fuel and oxygen.

[0013] The gearbox 23 is disposed in a power transmission path between the multiple electric motors 22 and the propeller 11. The gearbox 23 constitutes a reducer and transmits the rotation of the multiple electric motors 22 to the propeller 11 after reducing the speed. A clutch 24 is interposed between the gearbox 23 and the electric motor 22. The gearbox 23 has multiple input shafts 71 corresponding to the multiple electric motors 22, respectively, and the input shaft 71 is connected to the clutch 24. In addition, the output shaft 22a of the electric motor 22 is also connected to the clutch 24.

[0014] The clutch 24 is, for example, a sprag-type one-way clutch, but may be another type of clutch. The clutch 24 is configured to permit torque transmission from the output shaft 22a of the electric motor 22 to the input shaft 71 of the gearbox 23, and prohibit torque transmission from the input shaft 71 of the gearbox 23 to the output shaft 22a of the electric motor 22. Therefore, when one of the electric motors 22 is stopped, power is prevented from being transmitted from the gearbox 23 to the stopped electric motor 22. Note that examples of when one of the electric motors 22 is stopped include when the power supply to some of the electric motors 22 is turned off to reduce the propeller output, or when a malfunction occurs in one of the electric motors 22.

[0015] The gearbox 23 has an output shaft 72. The propeller 11 is connected to the output shaft 72. The hub 11a may be directly connected to the front end of the output shaft 72, or may be indirectly connected to the front end of the output shaft 72 via another shaft member. A detailed configuration of the gearbox 23 will be described later.

[0016] (lubrication device) The propulsion system 10A includes a lubrication device 40. The lubrication device 40 supplies lubricating oil to a plurality of gears in the gear box 23. The lubrication device 40 includes an oil tank 41, a first pump 42, a heat exchanger 43, and a circulation path 44. The oil tank 41 stores oil. The oil stored in the oil tank 41 is, for example, lubricating oil to be supplied to the gear box 23.

[0017] The first pump 42 supplies the lubricating oil stored in the oil tank 41 to the gear box 23, for example. The first pump 42 is driven by power transmitted from the gear box 23. The first pump 42 supplies the oil to the gear box 23 at a pressure different from the pressure of the oil supplied to the actuator 34 by the second pump 32 described later. The first pump 42 supplies the oil to the gear box 23 at a pressure lower than the pressure of the oil supplied to the actuator 34 by the second pump 32, for example. The second pump 32 and the first pump 42 may also be referred to as a high-pressure pump and a low-pressure pump, respectively. In addition, the lubrication device 40 is, for example, a dry sump type, and the oil tank 41 and the first pump 42 are disposed outside the gear box 23.

[0018] The heat exchanger 43 cools the oil flowing through the circulation path 44. The heat exchanger 43 is, for example, an air-cooled type. An air intake 5a is arranged in the nacelle 5 of the aircraft 1 (see FIG. 1). The heat exchanger 43 cools the oil using air flowing in from the air intake 5a as a refrigerant. The air intake 5a is arranged, for example, on the outer wall of the nacelle 5, but may also be arranged in the center of the propeller 11 or in the periphery of the propeller 11.

[0019] The oil tank 41, the first pump 42, the heat exchanger 43, and the gear box 23 are disposed in a circulation path 44. Oil circulates between the gear box 23 and the heat exchanger 43 through the circulation path 44. That is, the first pump 42 is driven to supply the lubricating oil stored in the oil tank 41 to the gear box 23. The lubricating oil is heated as it passes through the gear box 23, and after flowing out of the gear box 23, is sent to the heat exchanger 43 where it is cooled, and then returned to the oil tank 41.

[0020] (Pitch change device) The propulsion system 10A includes a pitch change device 30 that changes the pitch of the blades 11b. That is, the propeller 11 is a variable pitch propeller that can change the pitch angle of the blades 11b.

[0021] The pitch change device 30 has an oil tank 31, a second pump 32, a control valve 33, an actuator 34, and a pitch change mechanism 35. In this embodiment, the actuator 34 is a hydraulic actuator, but is not limited to this. The oil tank 31 stores oil. The oil stored in the oil tank 31 is, for example, hydraulic oil used as a power transmission medium in the actuator 34. It is sufficient that the pitch change device 30 includes at least one of the actuator 34 or the control valve 33.

[0022] The second pump 32 is disposed in a circulation path 36 between the oil tank 31 and the actuator 34. The second pump 32 supplies, for example, the hydraulic oil stored in the oil tank 31 to the actuator 34 via the circulation path 36. The second pump 32 is driven by power transmitted from the gear box 23. The oil tank 31 and the second pump 32 are disposed outside the gear box 23.

[0023] The control valve 33 controls the operation of the actuator 34. The control valve 33 is disposed in an oil passage between the discharge port of the second pump 32 and the actuator 34. The control valve 33 changes its opening degree based on a control command received from a controller disposed in the aircraft 2, for example, to adjust the pressure of the hydraulic oil supplied to the actuator 34.

[0024] The actuator 34 changes the pitch angle of the blades 11b. The actuator 34 is, for example, a hydraulic cylinder. When the actuator 34 is a hydraulic cylinder, the actuator 34 has at least one hydraulic chamber, a piston that is displaced along the rotation axis of the propeller 11 by the pressure of the hydraulic chamber, and a rod that is displaced together with the piston. The motion of the rod is transmitted to a pitch change mechanism 35 in the hub 11a of the propeller 11 via a rod-shaped body that extends inside the gearbox 23 along the rotation axis of the propeller 11. The control valve 33 is, for example, a directional control valve that can switch the supply destination of the hydraulic oil between a rod-side hydraulic chamber and a head-side hydraulic chamber included in the actuator 34 based on a control command received from a controller arranged in the aircraft 2.

[0025] The pitch change mechanism 35 is disposed within the hub 11a of the propeller 11, and converts the motion of the rod of the actuator 34 into rotational motion around the longitudinal axis of the blades 11b. The pitch change mechanism 35 may be disposed outside the hub 11a of the propeller 11. The actuator 34 drives the multiple blades 11b via the pitch change mechanism 35 so as to achieve a pitch that corresponds to the pressure of the supplied hydraulic oil.

[0026] (cooling device) The propulsion system 10A is equipped with cooling devices 50 and 60.

[0027] The cooling device 50 cools the multiple electric motors 22. The cooling device 50 has a water tank 51, a water pump 52, a heat exchanger 53, and a circulation path 54. The water tank 51 stores water to be used as cooling water. Note that the cooling device 50 can use liquids other than water. The water tank 51 can store liquids other than water.

[0028] The water pump 52 supplies water stored in the water tank 51 to the multiple electric motors 22. The water pump 52 may be of an electric type or a mechanical type.

[0029] The heat exchanger 53 cools the water flowing through the circulation path 54. The heat exchanger 53 is, for example, an air-cooled type. An air intake 5a is arranged in the nacelle 5 of the aircraft 1. The air intake 5a is arranged, for example, on the outer wall of the nacelle 5, but may be arranged in the center of the propeller 11 or in the periphery of the propeller 11. The heat exchanger 53 cools the water that has flowed into the heat exchanger 53 using the air that has flowed in from the air intake 5a as a refrigerant.

[0030] The water tank 51, the water pump 52, the heat exchanger 53, and the electric motors 22 are disposed in a circulation path 54. Cooling water circulates between the electric motors 22 and the heat exchanger 53 through the circulation path 54. That is, the water pump 52 is driven to supply water stored in the water tank 51 to the electric motors 22. In FIG. 2, the circulation path 54 includes a series of flow paths that supply water to the electric motors 22, but the circulation path 54 is not limited thereto. For example, the circulation path 54 may include a plurality of parallel branch paths that branch off from a water path extending from the water pump 52 and connect to the electric motors 22. The cooling water is heated by passing through the electric motors 22, and after passing through the electric motors 22, is sent to the heat exchanger 53 to be cooled, and then returned to the water tank 51.

[0031] The cooling device 60 cools the battery 21. The cooling device 60 has a water tank 61, a water pump 62, a heat exchanger 63, and a circulation path 64. The water tank 61 stores water to be used as cooling water.

[0032] The water pump 62 supplies water stored in the water tank 61 to the battery 21. The water pump 62 may be, for example, an electric type or a mechanical type.

[0033] The heat exchanger 63 cools the water flowing through the circulation path 64. The heat exchanger 63 is, for example, an air-cooled type. An air intake 5a is arranged in the nacelle 5 of the aircraft 1. The air intake 5a is arranged, for example, on the outer wall of the nacelle 5, but may be arranged in the center of the propeller 11 or in the periphery of the propeller 11. The heat exchanger 63 cools the water that has flowed into the heat exchanger 63 using the air that has flowed in from the air intake 5a as a refrigerant.

[0034] The water tank 61, the water pump 62, the heat exchanger 63, and the battery 21 are disposed in a circulation path 64. Cooling water circulates between the battery 21 and the heat exchanger 63 through the circulation path 64. That is, the water pump 62 is driven to supply water stored in the water tank 61 to the battery 21. The cooling water is heated by passing through the battery 21, and after passing through the battery 21, it is sent to the heat exchanger 63 where it is cooled, and then returned to the water tank 61.

[0035] Next, details of the gearbox 23 will be described with reference to Figs. 3 to 7. Fig. 3 is a perspective view of the configuration in the vicinity of the gearbox 23 in the propulsion system 10A of Fig. 2. Fig. 4 is a front view of the configuration in the vicinity of the gearbox 23 in the propulsion system 10A of Fig. 2. Fig. 5 is a rear view of the configuration in the vicinity of the gearbox 23 in the propulsion system 10A of Fig. 2. Fig. 6 is a side view of the configuration in the vicinity of the gearbox 23 in the propulsion system 10A of Fig. 2. Fig. 7 is a side cross-sectional view of the configuration in the vicinity of the gearbox 23 in the propulsion system 10A of Fig. 2.

[0036] The gearbox 23 includes a housing 73 that houses a plurality of gears. As shown in Fig. 3, the housing 73 is generally frustum-shaped and has a diameter that decreases toward the front along the rotation axis X1 of the propeller 11. The housing 73 includes, for example, a first cylindrical portion 73a, a second cylindrical portion 73b, a back surface portion 73c, and two semi-cylindrical portions 73d. A gear housing space S is formed by the first cylindrical portion 73a, the second cylindrical portion 73b, the back surface portion 73c, and the two semi-cylindrical portions 73d.

[0037] As shown in Fig. 7, the first cylindrical portion 73a opens in the front-rear direction. The first cylindrical portion 73a is a generally hollow truncated cone whose center line coincides with the rotation axis X1 of the propeller 11. The output shaft 72 of the gearbox 23 protrudes forward so as to pass through the front opening of the first cylindrical portion 73a. The diameter of the first cylindrical portion 73a increases toward the rear.

[0038] The second cylindrical portion 73b opens in the front-rear direction. The second cylindrical portion 73b has a substantially cylindrical shape whose center line coincides with the rotation axis X1 of the propeller 11. A front opening edge of the second cylindrical portion 73b is connected to a rear opening edge of the first cylindrical portion 73a.

[0039] The rear portion 73c is connected to the edge of the rear opening of the second cylindrical portion 73b so as to close the rear opening of the second cylindrical portion 73b. The rear portion 73c is disk-shaped. The rear portion 73c has a plurality of openings.

[0040] As shown in FIG. 4, two semi-cylinder portions 73d are connected to the second cylindrical portion 73b. The semi-cylinder portions 73d are substantially semi-cylinder-shaped with a center line parallel to the rotation axis X1 of the propeller 11. The semi-cylinder portions 73d are hollow and open to the second cylindrical portion 73b side. The two semi-cylinder portions 73d form a space for accommodating at least a part of the pump drive gears 91, 92 described below. The space covered by the semi-cylinder portions 73d communicates with the inner space of the second cylindrical portion 73b. The second cylindrical portion 73b has two openings on the sides, and the two openings are closed by the two semi-cylinder portions 73d.

[0041] A mount frame 26 for supporting the gearbox 23 within the nacelle 5 is fixed to the housing 73. The mount frame 26 includes an annular fixed frame 26a and a plurality of support frames 26b connecting the fixed frame 26a and the housing 73. The fixed frame 26a is located rearward of the gearbox 23, and the plurality of support frames 26b extend forward from the fixed frame 26a toward the housing 73 of the gearbox 23. A front end of the support frame 26b is fixed to a mount support portion 73e protruding outward in the radial direction R from the second cylindrical portion 73b.

[0042] As shown in FIG. 5, the electric motors 22 are arranged at equal intervals in the circumferential direction around the rotation axis X1 of the propeller 11 behind the gearbox 23. As shown in FIG. 5, the electric motors 22 are equidistant from the rotation axis X1 of the propeller 11. The circumferential intervals and distances of the electric motors 22 around the rotation axis X1 of the propeller 11 may not be equal. As shown in FIG. 6, the rotation axis X2 of each electric motor 22 is parallel to the rotation axis X1 of the propeller 11. The rotation axis X2 of each electric motor 22 may not be parallel to the rotation axis X1 of the propeller 11. When the propulsion system 10A is viewed from the front in the direction along the rotation axis X1 of the propeller 11, the electric motor 22 overlaps all or a part of the gearbox 23. At least a part of the electric motor 22 is disposed radially inward from the outermost end of the housing 73 in the radial direction R. In this embodiment, the rotation axis X2 of the electric motor 22 is disposed inward in the radial direction R from the outermost end of the housing 73 in the radial direction R. Note that the outer end of the housing 73 in the radial direction R is a part of the housing 73 that is located farthest from the rotation axis X1 of the propeller 11 when viewed in the direction along the rotation axis X1 of the propeller 11. In this embodiment, the outermost end of the housing 73 in the radial direction R is a part of the side surface of the semi-cylinder portion 73d.

[0043] 5, at least one electric motor 22 of the multiple motors is disposed in the nacelle 5 such that a gap between the at least one electric motor 22 and the nacelle 5 is equal to or greater than a predetermined value when viewed in a direction along the rotation axis X1 of the propeller 11. The predetermined value is, for example, 50 cm, and preferably equal to or greater than 40 cm. By ensuring a predetermined gap between the electric motor 22 and the nacelle 5, repair or replacement work of the electric motor 22 in the nacelle 5 can be easily performed.

[0044] For example, in this embodiment, the at least one electric motor 22 may have a gap between the at least one electric motor 22 and the nacelle 5 equal to or greater than the predetermined value in a cross section perpendicular to the rotation axis X1 of the propeller 11. The cross section perpendicular to the rotation axis X1 of the propeller 11 may be a cross section passing through the at least one electric motor 22, or may be a cross section passing through the support frame 26b.

[0045] 5, in this embodiment, the inner circumferential surface of the nacelle 5 coincides with the outer circumferential surface of the fixed frame 26a when viewed in the direction along the rotation axis X1 of the propeller 11. The gap between the at least one electric motor 22 and the abutting portion of the nacelle 5 with the mount frame 26 when viewed in the direction along the rotation axis X1 of the propeller 11 may be equal to or greater than the predetermined value.

[0046] It is preferable that a distance t1 between the rotation axis X2 of the electric motor 22 and the outer end of the mount frame 26 in the radial direction R is greater than a distance t2 between the rotation axis X1 of the propeller 11 and the rotation axis X2 of the electric motor 22. By making the distance t1 greater than the distance t2, repair or replacement work of the electric motor 22 inside the nacelle 5 becomes easier.

[0047] As shown in Fig. 3, the first pump 42 and the oil tank 41 are disposed outside the housing 73 of the gearbox 23. In addition, the second pump 32 and the oil tank 31 are disposed outside the housing 73 of the gearbox 23. As shown in Fig. 4, the first pump 42 and the second pump 32 overlap with the gearbox 23 when viewed in a direction along the rotation axis X1 of the propeller 11. In addition, the first pump 42 and the second pump 32 overlap with the gearbox 23 when viewed in the radial direction R.

[0048] 6, the first pump 42 and the second pump 32 are disposed outward of the gear box 23 in the radial direction R. The first pump 42, the second pump 32, and the gear box 23 are disposed so as to intersect with an imaginary plane perpendicular to the rotation axis X1 of the propeller 11. The first pump 42 overlaps with the first cylindrical portion 73a of the housing 73 when viewed in the radial direction R. Although not shown, the second pump 32 overlaps with the first cylindrical portion 73a of the housing 73 when viewed in the radial direction R.

[0049] At least a part of the pitch change device 30 is disposed rearward of the gear box 23. At least a part of the pitch change device 30 is disposed on the rotation axis X1 of the propeller 11. At least a part of the pitch change device 30 is disposed inward in the radial direction R from the multiple electric motors 22. Specifically, as shown in FIG. 6 , the control valve 33 and the actuator 34 in the pitch change device 30 are configured as one unit, and the unit is connected to a rear part 73c of the housing 73. The control valve 33 and the actuator 34 are disposed inward in the radial direction R from the multiple electric motors 22. The control valve 33 and the actuator 34 are disposed on the rotation axis X1 of the propeller 11.

[0050] A part of the actuator 34 may extend inside the gearbox housing 73. For example, the hydraulic chamber and piston of the actuator 34 may be located rearward of the rearmost end of the housing 73, and the rod of the actuator 34 may pass through an opening in the rear portion 73c, with the rod part extending inside the housing 73.

[0051] The actuator 34 may be disposed radially inward of the rotation axis X2 of the multiple electric motors 22. The rearmost end of the actuator 34 may be located forward of the rearmost ends of the multiple electric motors 22. The rearmost end of the control valve 33 may be located forward of the rearmost ends of the multiple electric motors 22.

[0052] One or both of the control valve 33 and the actuator 34 do not have to be arranged on the inside in the radial direction R of the multiple electric motors 22. In addition, one or both of the control valve 33 and the actuator 34 do not have to be arranged on the rotation axis X1 of the propeller 11.

[0053] (Gearbox details) As shown in FIG. 7, the housing 73 of the gearbox 23 accommodates a plurality of pinion gears 81, a first sun gear 82, a second sun gear 83, a transmission shaft 84, a plurality of planetary gears 85, a ring gear 86, and a planetary carrier 87.

[0054] The number of the pinion gears 81 is the same as the number of the electric motors 22. The pinion gears 81 are fixed to the input shaft 71 driven by the electric motor 22. The pinion gears 81 are positioned at equal distances from the rotation axis X1 of the propeller 11.

[0055] The first sun gear 82 is disposed radially inward of the multiple pinion gears 81 in the radial direction R perpendicular to the rotation axis X1 of the propeller 11. The center of the first sun gear 82 is located on the rotation axis X1 of the propeller 11. The multiple pinion gears 81 engage with the first sun gear 82. The first sun gear 82 has a relatively large diameter so as to engage with the multiple pinion gears 81. For example, the diameter of the first sun gear 82 is 50% or more of the diameter of the second cylindrical portion 73b of the housing 73.

[0056] The second sun gear 83 is disposed in front of the first sun gear 82. The center of the second sun gear 83 is located on the rotation axis X1 of the propeller 11. The transmission shaft 84 extends along the rotation axis X1 of the propeller 11. The transmission shaft 84 has a first end which is a rear end and a second end which is a front end, the first sun gear 82 is fixed to the first end, and the second sun gear 83 is fixed to the second end. In this manner, the first sun gear 82 and the second sun gear 83 are connected by the transmission shaft 84. The transmission shaft 84 is, for example, cylindrical and opens in the front-rear direction, and a part of the pitch change device 30 can pass through the inside of the transmission shaft 84.

[0057] Planetary gear 85 is disposed radially outward of second sun gear 83 in radial direction R perpendicular to rotation axis X1 of propeller 11. Planetary gear 85 engages with second sun gear 83.

[0058] The ring gear 86 is disposed radially outward of the plurality of planetary gears 85 in a radial direction R perpendicular to the rotation axis X1 of the propeller 11. The ring gear 86 is engaged with the plurality of planetary gears 85.

[0059] The planetary carrier 87 has a generally hollow truncated cone shape that decreases in diameter toward the front along the rotation axis X1 of the propeller 11. The planetary carrier 87 is connected to a plurality of planetary gears 85. The planetary carrier 87 rotates together with the plurality of planetary gears 85 about the rotation axis X1 of the propeller 11.

[0060] Specifically, planetary gear 85 has bearings 85a that support a carrier shaft, and the carrier shaft supported by each bearing 89a is fixed to the rear end of planetary carrier 87. Therefore, planetary gear 85 revolves around second sun gear 83 along ring gear 86 while rotating due to the rotation of second sun gear 83. As planetary gear 85 revolves around rotation axis X1 of propeller 11, planetary carrier 87 connected to planetary gear 85 via a carrier shaft rotates around rotation axis X1.

[0061] A front end of the planetary carrier 87 is connected to a rear end of an output shaft 72 extending in the front-rear direction. The output shaft 72 is supported by a bearing fixed to a housing 73. The output shaft 72 protrudes forward from the housing 73. A propeller 11 is connected to the front end of the output shaft 72.

[0062] With the above configuration, in gear box 23 of this embodiment, two-stage reduction in speed is performed in the process of transmitting power from input shaft 71 to output shaft 72. That is, a first-stage reduction in speed is performed by power transmission from pinion gear 81 to first sun gear 82, and a second-stage reduction in speed is performed by power transmission from second sun gear 83 to planetary carrier 87.

[0063] 4, a plurality of pump drive gears 91, 92 are housed in housing 73. The plurality of pump drive gears 91 include at least one first pump drive gear 92 that transmits power from gear box 23 to first pump 42, and at least one second pump drive gear 91 that transmits power from gear box 23 to second pump 32. The first pump drive gear 92 and the second pump drive gear 91 are disposed outward in radial direction R of first sun gear 82, and rotate together with first sun gear 82.

[0064] 4, a first pump driving gear 92 is engaged with the first sun gear 82. The center of the first pump driving gear 92 is located on the pump axis of the first pump 42. The pump shaft of the first pump 42 penetrates the housing 73 and is connected to the first pump driving gear 92. In this way, power is transmitted to the first pump 42 from the electric motor 22 via the gear box 23.

[0065] Further, a second pump drive gear 91a is engaged with the first sun gear 82, and a second pump drive gear 91b is further engaged with the second pump drive gear 91a. The center of the second pump drive gear 91b is located on the pump axis of the second pump 32. The pump shaft of the second pump 32 penetrates the housing 73 and is connected to the second pump drive gear 91b. In this way, the second pump 32 receives power from the electric motor 22 via the gear box 23.

[0066] The number of the first pump drive gear 92 does not have to be one, and the number of the second pump drive gears 91 does not have to be two. In addition, the ratio of the diameters of the first pump drive gear 92 and the second pump drive gear 91 is not particularly limited. For example, the number and diameters of the first pump drive gear 92 and the second pump drive gear 91 can be determined so that the rotation speed of the first pump 42 is higher than the rotation speed of the second pump 32. In FIG. 4, the pump shafts of the first pump 42 and the second pump 32 are shown to be positioned equidistant from the rotation axis X1, but the positions of the first pump 42 and the second pump 32 can also be changed as appropriate.

[0067] (Action and effect) As described above, in the propulsion system 10A according to this embodiment, the first pump 42, which is a low-pressure pump that supplies lubricating oil for cooling the gearbox 23, and the second pump 32, which is a high-pressure pump that supplies hydraulic oil for driving the actuator 34, are both driven by power transmitted from the gearbox 23. Therefore, it is possible to change the pitch angle of the blades 11b and supply lubricating oil to the gearbox 23 without requiring an electric motor or the like for driving the pump. Therefore, an increase in the weight of the propulsion system 10A of the aircraft 1 can be suppressed.

[0068] Furthermore, according to this embodiment, the first pump 42, the second pump 32, and the gearbox 23 are arranged so as to intersect with an imaginary plane perpendicular to the rotation axis X1 of the propeller 11. In this manner, by arranging the first pump 42 and the second pump 32 around the gearbox 23, it is possible to realize a compact propulsion system 10A as a whole. In particular, in this embodiment, the housing 73 of the gearbox 23 is substantially frustum-shaped, and the first pump 42 and the second pump 32 are arranged around the first cylindrical portion 73a, so that the space around the first cylindrical portion 73a can be effectively utilized.

[0069] Furthermore, according to this embodiment, the first pump 42 and the second pump 32 are disposed outside the gear box 23, so that the first pump 42 and the second pump 32 can be easily repaired or replaced.

[0070] According to this embodiment, the heat exchanger 43 cools the oil using, as a refrigerant, air flowing in from the air intake 5a located in the periphery of the propeller 11 of the aircraft 1. In this way, by taking in air from the periphery of the propeller 11, it is possible to easily take in the gas that serves as the refrigerant. The air intake 5a may be located on the outer wall of the nacelle 5 or in the periphery of the propeller 11.

[0071] Furthermore, according to this embodiment, first sun gear 82 is engaged with multiple pinion gears 81 and has a relatively large diameter. Therefore, pump drive gear 91 can be easily disposed so as to engage with first sun gear 82, and power for driving the pump can be easily obtained from first sun gear 82.

[0072] <Second embodiment> 8 is a block diagram of an aircraft propulsion system 10B according to the second embodiment. The propulsion system 10B includes a cooling device 100 instead of the cooling devices 50 and 60 of the first embodiment. The cooling device 100 functions as both the cooling devices 50 and 60 of the first embodiment. In this embodiment and the third, fourth, and fifth embodiments described below, elements that are the same as or similar to those of the first embodiment are denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted.

[0073] The cooling device 100 cools the battery 21 and the multiple electric motors 22. The cooling device 100 has a water tank 101, a water pump 102, a heat exchanger 103, and a circulation path 104. The water tank 101 stores water to be used as cooling water. The water pump 102 supplies the water stored in the water tank 101 to the battery 21 and the multiple electric motors 22. The water pump 102 may be, for example, an electric type or a mechanical type.

[0074] The heat exchanger 103 cools the water flowing through the circulation path 104. The heat exchanger 103 is, for example, an air-cooled type. An air intake 5a is arranged in the nacelle 5 of the aircraft 1, and the heat exchanger 103 cools the water that has flowed into the heat exchanger 103 using the air that has flowed in from the air intake 5a as a refrigerant.

[0075] The water tank 101, the water pump 102, the heat exchanger 103, the battery 21, and the multiple electric motors 22 are disposed in a circulation path 104. Cooling water circulates between the battery 21 and the multiple electric motors 22 and the heat exchanger 103 through the circulation path 104. That is, when the water pump 102 is driven, water stored in the water tank 101 is supplied to the battery 21 and the multiple electric motors 22. The cooling water is heated by passing through the battery 21 and the multiple electric motors 22, and after passing through the battery 21 and the multiple electric motors 22, it is sent to the heat exchanger 103 and cooled, and then returned to the water tank 101.

[0076] In FIG. 8, the circulation path 104 includes a series of flow paths that sequentially supply water to the multiple electric motors 22, but the circulation path 104 is not limited to this. For example, the circulation path 104 may include a plurality of parallel branch paths that branch off from a water path extending from the water pump 102 and connect to the multiple electric motors 22. In addition, in FIG. 8, the circulation path 104 guides the cooling water discharged from the water pump 102 to the multiple electric motors 22 and guides the cooling water that has passed through the multiple electric motors 22 to the battery 21, but the circulation path 104 may guide the cooling water discharged from the water pump 102 to the battery 21 and guide the cooling water that has passed through the battery 21 to the multiple electric motors 22. In addition, in FIG. 8, the circulation path 104 includes a series of flow paths that supply water to the battery 21 and the electric motor 22, but the circulation path 104 is not limited to this. For example, the circulation path 104 may include a plurality of parallel branch paths that branch off from a water path extending from the water pump 102 and connect to the battery 21 and the electric motor 22.

[0077] The present embodiment also provides the same effects as those of the first embodiment. Furthermore, in the present embodiment, only one heat exchanger is required to cool the battery 21 and the multiple electric motors 22, and the entire propulsion system can be made compact.

[0078] <Third embodiment> 9 is a block diagram of an aircraft propulsion system 10C according to a third embodiment. In the propulsion system 10C, the cooling device 100 of the second embodiment cools the lubricating oil flowing through the circulation path 44. That is, in this embodiment, the heat exchanger 103 of the cooling device 100 also functions as a heat exchanger of the lubrication device 40.

[0079] The lubrication device 110 supplies lubricating oil to a plurality of gears in the gear box 23. The lubrication device 110 has an oil tank 41, a first pump 42, a heat exchanger 103, and a circulation path 111. The oil tank 41, the first pump 42, the heat exchanger 103, and the gear box 23 are arranged in the circulation path 111. The circulation path 111 is an example of a first circulation path. The water tank 101, the water pump 102, the plurality of motors 22, and the battery 21 are arranged in a circulation path 104. The circulation path 104 is an example of a second circulation path, and the water pump 102 is an example of a third pump.

[0080] Oil circulates between the gear box 23 and the heat exchanger 103 through the circulation path 111. That is, the first pump 42 is driven to supply the lubricating oil stored in the oil tank 41 to the gear box 23. The lubricating oil is heated as it passes through the gear box 23, and after flowing out of the gear box 23, is sent to the heat exchanger 103 where it is cooled, and then returned to the oil tank 41.

[0081] In this manner, heat exchanger 103 is disposed so that circulation paths 111 and 104 pass through it, and the oil flowing through circulation path 111 and the water flowing through circulation path 104 are cooled by the air flowing in from air intake 5a.

[0082] The present embodiment also provides the same effects as the first embodiment. Furthermore, in the present embodiment, the cooling of the liquid heated by the electric motor 22 and the battery 21 and the cooling of the oil supplied to the gear box 23 can be performed by the same heat exchanger 103, so that the entire propulsion system can be made compact.

[0083] <Fourth embodiment> FIG. 10 is a block diagram of an aircraft propulsion system 10D according to a fourth preferred embodiment. In the propulsion system 10D, the lubricating oil for the gearbox 23 is cooled by water cooled by the heat exchanger 103 of the cooling arrangement 100.

[0084] The lubrication device 120 supplies lubricating oil to a plurality of gears in the gear box 23. The lubrication device 120 has an oil tank 41, a first pump 42, a heat exchanger 121, and a circulation path 122. The oil tank 41, the first pump 42, the heat exchanger 121, and the gear box 23 are arranged in the circulation path 122.

[0085] The heat exchanger 121 is, for example, a water-cooled type. The heat exchanger 121 is disposed so that the circulation path 122 and the circulation path 104 pass through it. The heat exchanger 121 cools the oil flowing through the circulation path 122 by the water flowing through the circulation path 104. The circulation path 111 and the heat exchanger 121 are examples of a first circulation path and a first heat exchanger, respectively. The water pump 102, the circulation path 104, and the heat exchanger 103 are examples of a third pump, a second circulation path, and a second heat exchanger, respectively.

[0086] The present embodiment also provides the same effects as the first embodiment. Furthermore, in the present embodiment, the liquid for cooling the electric motor 22 and the battery 21 is used to cool the oil supplied to the gear box 23. Therefore, even if it is difficult to arrange the heat exchanger 121 at a position where it can be cooled by air, the heat exchanger 121 can be cooled using the liquid for cooling the electric motor 22 and the battery 21, so that the degree of freedom in arranging the heat exchanger 121 is increased.

[0087] <Fifth embodiment> Fig. 11 is a block diagram of a propulsion system 10E of an aircraft according to a fifth embodiment. The propulsion system 10E includes a gas turbine 131 in addition to an electric motor 22 as a drive source for driving the propeller 11. In Fig. 11, a cooling device for cooling the battery 21 and the multiple electric motors 22, and a lubrication device for supplying lubricating oil to multiple gears in a gear box 23 are omitted.

[0088] The propulsion system 10E includes a plurality of electric motors 22 and a gas turbine 131. A clutch 132 is interposed between the gearbox 23 and the gas turbine 131. The gearbox 23 has an input shaft 171. A pinion gear that engages with the first sun gear 82 is fixed to the input shaft 171 of the gearbox 23, similar to the input shaft 71. The input shaft 171 is connected to the clutch 132. The clutch 132 is, for example, a one-way clutch. The clutch 132 is configured to permit torque transmission from the output shaft 131a of the gas turbine 131 to the input shaft 171 of the gearbox 23 and prohibit torque transmission from the input shaft 171 of the gearbox 23 to the output shaft 131a of the gas turbine 131. The clutch 24 and the clutch 132 are examples of a first clutch and a second clutch, respectively.

[0089] In this embodiment, the same effects as those in the first embodiment can be obtained. Furthermore, in this embodiment, power can be transmitted to the propeller 11 not only from the multiple electric motors 22 but also from the gas turbine 131.

[0090] <Other embodiments> Although the embodiment has been described above, the above configuration can be modified, deleted, or added within the scope of the present invention.

[0091] The configurations of the propulsion system described in the first to fifth embodiments are examples and are not limited to the above. For example, the first, second, third, fourth, and fifth embodiments can be appropriately combined. The position, structure, shape, number, and the like of each element of the propulsion system are not limited to the above embodiments.

[0092] For example, although an aircraft having four propellers has been described in the first to fifth embodiments, the aircraft is not limited thereto. For example, the aircraft may be a single-engine aircraft having one propeller disposed at the front end of the aircraft, a twin-engine aircraft having one propeller on each of the left and right main wings, or a three-engine aircraft having one propeller on the front end of the aircraft and on each of the left and right main wings.

[0093] In the first to fifth embodiments, the propulsion system is disposed in the nacelle 5 attached to the lower part of the main wing 3, but the propulsion system may be disposed in another part of the aircraft, in which case the aircraft does not need to include a nacelle. For example, the propulsion system may be disposed in the aircraft fuselage or in the main wing.

[0094] For example, the number of electric motors included in the propulsion system does not have to be four, but may be two, three, five or more.

[0095] In the first to fifth embodiments, the electric motors 22 are arranged at equal intervals in the circumferential direction around the rotation axis X1 of the propeller 11 behind the gearbox 23, but the arrangement of the electric motors 22 is not limited to this. Note that the configuration of the gearbox may be changed depending on the arrangement of the electric motors 22.

[0096] For example, the multiple electric motors included in the propulsion system may include electric motors arranged side by side in a direction parallel to the rotation axis of the propeller. This can further reduce the frontal projection area of ​​the entire system. For example, the propulsion system may include two electric motors arranged at intervals in the front-rear direction to the right of the rotation axis of the propeller, and two electric motors arranged at intervals in the front-rear direction to the left of the rotation axis of the propeller. In this case, the front electric motor may be located forward of the input shaft of the gearbox, and the rear electric motor may be located rearward of the input shaft of the gearbox.

[0097] Furthermore, for example, the multiple electric motors included in the propulsion system may include electric motors arranged side by side in a direction perpendicular to the rotation axis of the propeller. This allows the size in a direction perpendicular to the rotation axis of the propeller (a direction perpendicular to the direction in which the electric motors are arranged) to be reduced. For example, by arranging multiple electric motors in a horizontal direction perpendicular to the rotation axis of the propeller, the vertical dimension of the propulsion system can be reduced, making it easier to store the propulsion system inside the main wing of an aircraft.

[0098] In the first to fifth embodiments, the rotation axes X2 of all the electric motors 22 provided in the propulsion system are disposed inward in the radial direction R from the outer ends of the housing 73 in the radial direction R, in the radial direction R perpendicular to the rotation axis of the propeller, but this is not limited to this. For example, the rotation axes X2 of some of the electric motors 22 provided in the propulsion system may be disposed inward in the radial direction R from the outer ends of the housing 73 in the radial direction R.

[0099] In the first to fifth embodiments, the first pump 42, the second pump 32, and the gear box 23 are disposed so as to intersect with an imaginary plane perpendicular to the rotation axis X1 of the propeller 11, but the configuration of the propulsion system is not limited to this. The imaginary plane perpendicular to the rotation axis X1 of the propeller 11 that passes through the gear box 23 does not have to intersect with one or both of the first pump 42 and the second pump 32.

[0100] In the first to fifth embodiments, the first pump 42 and the second pump 32 are disposed outside the gear box 23, but one or both of the first pump 42 and the second pump 32 may be disposed inside the gear box 23. Also, instead of including one or both of the oil tanks 31, 41, the propulsion system may have an oil reservoir that stores oil inside the gear box.

[0101] In addition, the oil tanks 31 and 41 may be a single common tank. That is, oil tanks that store oil used as both the lubricating oil in the gear box 23 and the hydraulic oil in the actuator 34 may be disposed in both the circulation path 36 and the circulation path 44.

[0102] The actuator 34 does not have to be a hydraulic actuator. For example, the actuator 34 may be another type of actuator, such as an electric motor. In this case, the propulsion system does not have to include the second pump 32, the control valve 33, and the like.

[0103] In the first to fifth embodiments, the first pump 42 and the second pump 32 receive power from the first sun gear 82 of the gear box 23, but the method of extracting the power of the pump from the gear box is not limited to this. For example, the power of the pump may be extracted from a gear separately attached to the transmission shaft 84, or from a gear separately attached to the planetary carrier 87 or the output shaft 72. The configuration of the gear box 23 is not limited to that described in the first to fifth embodiments. In the first to fifth embodiments, the gear box is configured to perform two-stage reduction, but may be configured to perform one-stage or three or more stages of reduction. The first pump 42 and the second pump 32 may receive power from a mechanism other than the gear box 23. One or both of the first pump 42 and the second pump 32 may be electric.

[0104] Some or all of the water pumps described in the first to fifth embodiments may be driven by power transmitted from the gear box 23, similar to the first pump 42 and the second pump 32. In the first to fifth embodiments, the cooling device uses water as a liquid refrigerant, but the refrigerant is not limited to this and may be another liquid such as ethylene glycol. A clutch does not need to be interposed between the gear box and the electric motor.

[0105] The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general purpose processors, special purpose processors, integrated circuits, Application Specific Integrated Circuits (ASICs), conventional circuits, or any combination thereof, configured or programmed to perform the disclosed functions. Processors are considered processing circuits or circuits because they include transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed herein or other known hardware that is programmed or configured to perform the recited functions. Where the hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware or processor.

[0106] [Disclosure form] Each of the following aspects is a disclosure of a preferred embodiment.

[0107] [Aspect 1] A plurality of electric motors; A propeller having a plurality of blades whose pitch angle can be changed; a gear box that reduces the rotation of the electric motors and transmits the rotation to the propeller; An actuator for changing the pitch angle of the blade; a pump that is driven by power transmitted from the gear box and supplies oil to the gear box; a heat exchanger that cools the oil using at least one of a gas and a liquid as a refrigerant; and a circulation path through which oil circulates between the gearbox and the heat exchanger.

[0108] According to the above configuration, the pump for supplying oil as lubricating oil to the gearbox is driven by the power transmitted from the gearbox. Therefore, it is possible to supply lubricating oil to the gearbox without requiring an electric motor for driving the pump. Therefore, it is possible to suppress an increase in the weight of the aircraft propulsion system.

[0109] [Aspect 2] the pump is a first pump, The propulsion system of an aircraft as described in aspect 1, further comprising a second pump, separate from the first pump, driven by power transmitted from the gearbox and supplying oil to the actuator at a pressure different from the pressure of the oil supplied to the gearbox by the first pump.

[0110] According to the above configuration, the first pump, which is a pump for supplying oil to the gearbox as lubricating oil, and the second pump, which is a pump for supplying oil to drive the actuator, are both driven by power transmitted from the gearbox. Therefore, it is possible to supply lubricating oil to the gearbox and change the pitch angle of the blades without requiring an electric motor for driving the pump. Therefore, it is possible to suppress an increase in the weight of the aircraft propulsion system.

[0111] [Aspect 3] 3. The aircraft propulsion system of claim 2, wherein the first pump, the second pump, and the gearbox are arranged to intersect with an imaginary plane perpendicular to a rotational axis of the propeller.

[0112] According to the above configuration, by arranging the first pump and the second pump around the gearbox, it is possible to realize a compact propulsion system as a whole.

[0113] [Aspect 4] The gear box includes a plurality of gears and a housing that accommodates the plurality of gears. 4. The aircraft propulsion system of claim 2 or 3, wherein the first pump and the second pump are disposed outside the housing.

[0114] According to the above configuration, since the first pump and the second pump are located outside the housing of the gear box, maintenance of the first pump and the second pump can be easily performed.

[0115] [Aspect 5] the aircraft has an air intake; The heat exchanger is a heat exchanger that cools oil using air flowing in from the air intake port as a refrigerant, 5. An aircraft propulsion system as described in any one of aspects 1 to 4, wherein the air intake is located around the propeller of the aircraft.

[0116] According to the above configuration, by taking in air from the periphery of the propeller, the gas that serves as the refrigerant can be easily taken in.

[0117] [Aspect 6] The heat exchanger is a first heat exchanger, and the circulation path is a first circulation path, The propulsion system comprises: a battery for powering the plurality of electric motors; a third pump for supplying a liquid for cooling the electric motors or the battery; a second heat exchanger configured to cool the liquid; and A second circulation path through which a liquid circulates between the plurality of electric motors or the battery and the second heat exchanger, Aspects 6. The aircraft propulsion system according to any one of aspects 1 to 5, wherein the first heat exchanger is a heat exchanger that cools oil flowing through the first circulation path by liquid flowing through the second circulation path.

[0118] According to the above-mentioned configuration, the liquid for cooling the electric motor or the battery is used to cool the oil supplied to the gear box, so that the liquid for cooling the electric motor or the battery can be used effectively.

[0119] [Aspect 7] The circulation path is a first circulation path, The propulsion system comprises: a battery for powering the plurality of electric motors; a third pump for supplying a liquid for cooling the electric motors or the battery; A second circulation path through which a liquid circulates between the electric motors or the battery and the heat exchanger, 6. The aircraft propulsion system of claim 5, wherein the heat exchanger cools the oil flowing through the first circulation path and the liquid flowing through the second circulation path using air flowing in from the air intake.

[0120] According to the above configuration, the cooling of the liquid heated by the electric motor or the battery and the cooling of the oil supplied to the gearbox can be performed using the same heat exchanger, making it possible to make the entire propulsion system compact.

[0121] [Aspect 8] The gear box includes: pinion gears fixed to a plurality of input shafts driven by the plurality of electric motors; a sun gear engaged with the plurality of pinion gears; a transmission shaft fixed to the sun gear and disposed in a power transmission path between the electric motor and the propeller; a pump drive gear engaged with the sun gear and connected to the first pump or the second pump.

[0122] According to the above-described configuration, the sun gear is engaged with the multiple pinion gears and has a relatively large diameter, which makes it easy to arrange the pump drive gear so as to engage with the sun gear, and makes it easy to extract power for driving the pump from the sun gear.

[0123] [Aspect 9] 9. The aircraft propulsion system of any one of aspects 1 to 8, further comprising a plurality of clutches respectively connected to the plurality of electric motors and interposed between the gearbox and the plurality of electric motors.

[0124] According to the above configuration, if a malfunction occurs in any of the multiple electric motors, the effect on the propulsion system can be suppressed.

[0125] [Aspect 10] The clutch is a first clutch, The propulsion system comprises: A gas turbine engine; 10. The aircraft propulsion system of claim 9, further comprising: a second clutch interposed between the gearbox and the gas turbine engine.

[0126] With this configuration, power can be transmitted to the propeller not only from multiple electric motors but also from a gas turbine. [Explanation of symbols]

[0127] 1 :Aircraft 5: Nacelle 5a: Air intake 10A, 10B, 10C, 10D, 10E: Propulsion system 11: Propeller 11b: Blade 21:Battery 22: Electric motor 23: Gearbox 24: Clutch 31: Oil tank 32: Second pump 33: Control valve 34: Actuator 41: Oil tank 42: First pump 43,53,63,103,121: Heat exchanger 51, 61, 101: Water tank 52, 62, 102: Water pump 44,54,64,104,111,122: Circulation route 73: Housing 81: Pinion gear 82: 1st sun gear 83: 2nd sun gear 84: Transmission shaft 85: Planetary gear 86: Ring gear 87: Planetary Carrier 91, 92: Pump drive gear 131: Gas turbine 132: Clutch

Claims

1. A plurality of electric motors; A propeller having a plurality of blades whose pitch angle can be changed; a gear box that reduces the rotation of the electric motors and transmits the rotation to the propeller; An actuator for changing the pitch angle of the blade; a pump that is driven by power transmitted from the gear box and supplies oil to the gear box; a heat exchanger that cools the oil using at least one of a gas and a liquid as a refrigerant; and a circulation path through which oil circulates between the gearbox and the heat exchanger.

2. the pump is a first pump, 2. The propulsion system of claim 1, further comprising: a second pump that is driven by power transmitted from the gearbox separately from the first pump and supplies oil to the actuator at a pressure different from a pressure of oil supplied to the gearbox by the first pump.

3. 3. The aircraft propulsion system according to claim 2, wherein the first pump, the second pump and the gearbox are arranged so as to intersect with an imaginary plane perpendicular to a rotational axis of the propeller.

4. The gear box includes a plurality of gears and a housing that accommodates the plurality of gears.

4. The aircraft propulsion system according to claim 2, wherein the first pump and the second pump are disposed outside the housing.

5. the aircraft has an air intake; The heat exchanger is a heat exchanger that cools oil using air flowing in from the air intake port as a refrigerant, 3. The aircraft propulsion system according to claim 1, wherein the air intake is located around the propeller of the aircraft.

6. The heat exchanger is a first heat exchanger, and the circulation path is a first circulation path, The propulsion system comprises: a battery for powering the plurality of electric motors; a third pump for supplying a liquid for cooling the electric motors or the battery; a second heat exchanger configured to cool the liquid; and a second circulation path through which a liquid circulates between the electric motors or the battery and the second heat exchanger; Further comprising:

3. The aircraft propulsion system according to claim 1, wherein the first heat exchanger is a heat exchanger that cools oil flowing through the first circulation passage by liquid flowing through the second circulation passage.

7. The circulation path is a first circulation path, The propulsion system comprises: a battery for powering the plurality of electric motors; a third pump for supplying a liquid for cooling the electric motors or the battery; a second circulation path through which a liquid circulates between the electric motors or the battery and the heat exchanger; 6. The aircraft propulsion system according to claim 5, wherein the heat exchanger cools the oil flowing through the first circulation passage and the liquid flowing through the second circulation passage by air flowing in from the air intake.

8. The gear box includes: pinion gears fixed to a plurality of input shafts driven by the plurality of electric motors; a sun gear engaged with the plurality of pinion gears; a transmission shaft fixed to the sun gear and disposed in a power transmission path between the electric motor and the propeller; a pump drive gear engaged with the sun gear and connected to the first pump or the second pump.

9. 3. The aircraft propulsion system according to claim 1, further comprising a plurality of clutches respectively connected to the plurality of electric motors and interposed between the gearbox and the plurality of electric motors.

10. The clutch is a first clutch, The propulsion system comprises: A gas turbine engine; 10. The aircraft propulsion system of claim 9, further comprising a second clutch interposed between the gearbox and the gas turbine engine.

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