Cooling device and flying object

Abstract

To effectively cool a rotary electric machine with a simple configuration.SOLUTION: A cooling device (32) includes a tubular member (120) inserted inside a hollow rotor shaft (116), and a fluid delivery section (124) that circulates refrigerant through a refrigerant flow path (122) including a first partial flow path (122A) and a second partial flow path (122B). The first partial flow path and the second partial flow path are interconnected at a tip (E1) of the tubular member. A flow path cross-sectional area of the second partial flow path at the tip of the tubular member is larger than a flow path cross-sectional area of the second partial flow path at a base end (E2) of the tubular member.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a cooling device and an air vehicle. [Background technology]

[0002] In recent years, research and development has been conducted into technologies that contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] Patent Document 1 discloses a cooling mechanism for cooling a rotating electric machine mounted on an aircraft. A cooling hole is formed in the rotor shaft of the rotating electric machine from one end to the other. A portion of a coolant supply pipe fixed to the aircraft is inserted into the cooling hole. A refrigerant flows through the coolant supply pipe from a base end located outside the cooling hole to a tip end located inside the cooling hole. The refrigerant that flows out from the tip of the coolant supply pipe into the cooling hole flows to the outside of the rotating electric machine through a gap between the inner circumferential surface of the rotor shaft and the outer circumferential surface of the coolant supply pipe. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-077131 Summary of the Invention [Problem to be solved by the invention]

[0005] Recently, there has been a demand for a simple structure to effectively cool a rotating electrical machine.

[0006] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0007] A first aspect of the present disclosure is a cooling device for cooling a rotating electric machine including a stator, a rotor, and a rotor shaft that rotates integrally with the rotor, the cooling device comprising: a tubular member inserted into the hollow rotor shaft; a liquid delivery unit that circulates a refrigerant through a refrigerant flow path that includes a first partial flow path located between the inner surface of the rotor shaft and the outer surface of the tubular member; and a second partial flow path formed by an internal cavity of the tubular member, wherein the first partial flow path and the second partial flow path are connected to each other at the tip of the tubular member, and the flow path cross-sectional area of ​​the second partial flow path at the tip of the tubular member is larger than the flow path cross-sectional area of ​​the second partial flow path at the base end of the tubular member.

[0008] A second aspect of the present disclosure is an aircraft including the cooling device according to the first aspect and the rotating electric machine. [Effects of the Invention]

[0009] This allows the rotating electrical machine to be cooled effectively with a simple configuration. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of the aircraft. [Figure 2] FIG. 2 is a diagram showing the configuration of the rotating electrical machine and the cooling device according to the first embodiment. [Figure 3] FIG. 3 is a diagram showing the flow of the refrigerant when the rotating electric machine according to the first embodiment rotates in a first rotation direction. [Figure 4] FIG. 4 is a diagram showing the flow of the refrigerant when the rotating electric machine according to the first embodiment rotates in the second rotation direction. [Figure 5] FIG. 5 is a diagram showing the configuration of a rotating electrical machine and a cooling device according to the second embodiment. [Figure 6] FIG. 6 is a diagram showing the flow of the refrigerant when the rotating electric machine according to the second embodiment rotates in the first rotation direction. [Figure 7] FIG. 7 is a diagram showing the flow of the refrigerant when the rotating electric machine according to the second embodiment rotates in the second rotation direction. DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) 1 is a perspective view of an aircraft 10. In this embodiment, the aircraft 10 is an eVTOL aircraft, but is not limited to this. For example, the aircraft 10 may be a multicopter.

[0012] The aircraft 10 comprises a fuselage 12, a front wing 14, a rear wing 16, multiple booms 18, multiple propeller units 20 for takeoff and landing, and multiple propeller units 22 for cruising. The fuselage 12 is long in the longitudinal direction. The front wing 14 is located forward of the midpoint of the fuselage 12 in the longitudinal direction. The front wing 14 is connected to the upper part of the fuselage 12. The rear wing 16 is located rearward of the midpoint of the fuselage 12 in the longitudinal direction. The rear wing 16 is connected to the fuselage 12 via a pylon 24.

[0013] The multiple booms 18 each extend in the fore-and-aft direction. The multiple booms 18 include a right boom 18R and a left boom 18L. The right boom 18R is disposed to the right of the fuselage 12. The right boom 18R curves in an arc toward the right. The right boom 18R is connected to the right wing tip of the front wing 14 and is connected to the right wing of the rear wing 16. The left boom 18L is disposed to the left of the fuselage 12. The left boom 18L curves in an arc toward the left. The left boom 18L is connected to the left wing tip of the front wing 14 and is connected to the left wing of the rear wing 16. Note that the right boom 18R and the left boom 18L may be straight.

[0014] Each boom 18 is provided with a plurality of propeller devices 20. In this embodiment, each boom 18 is provided with four propeller devices 20. However, each boom 18 may be provided with two, three, five or more propeller devices 20. In each boom 18, the four propeller devices 20 are arranged at intervals in the extension direction of the boom 18.

[0015] Each of the multiple propeller devices 20 has an identically structured housing 26, propeller 28, rotating electric machine 30, and cooling device 32. The housing 26 is configured to include a frame that forms the skeleton of the boom 18 and a fairing that covers the frame. The housing 26 houses the rotating electric machine 30 and the cooling device 32. The propeller 28 is located above the housing 26 and is rotatably attached to the housing 26. The rotating electric machine 30 rotates the propeller 28. The rotation directions of two or more propellers 28 of the multiple propeller devices 20 may differ. The cooling device 32 cools the rotating electric machine 30.

[0016] The fuselage 12 is equipped with a plurality of propeller devices 22. In this embodiment, the fuselage 12 is equipped with two propeller devices 22. The fuselage 12 may be equipped with one or three or more propeller devices 22. The two propeller devices 22 are arranged side by side on the left and right at the rear end of the fuselage 12.

[0017] FIG. 2 is a diagram showing the configuration of a rotating electric machine 30 and a cooling device 32 according to the first embodiment. The rotating electric machine 30 is fixed with its axis (center of rotation) X aligned along the vertical direction. For example, the rotating electric machine 30 is fixed to the frame of the accommodation section 26. Driving power is supplied to the rotating electric machine 30 from a power source via an inverter circuit. The rotating electric machine 30 rotates around its axis X in a first rotation direction D1 or a second rotation direction D2 depending on the driving power. The rotating electric machine 30 has a housing 110, a stator 112, a rotor 114, a rotor shaft 116, and two bearings 118.

[0018] The housing 110 is formed by combining multiple members. The housing 110 accommodates a stator 112, a rotor 114, and a portion of a rotor shaft 116. The stator 112 is fixed to the housing 110. The rotor 114 is disposed inside the stator 112 and fixed to the rotor shaft 116. The rotor shaft 116 is rotatably supported in the housing 110 by two bearings 118. One of the two bearings 118 is a first bearing 118A that rotatably supports the rotor shaft 116 above the rotor 114. The other of the two bearings 118 is a second bearing 118B that rotatably supports the rotor shaft 116 below the rotor 114.

[0019] The upper end of the rotor shaft 116 is located inside the gearbox 119. The gearbox 119 has a plurality of gears (not shown) that connect the rotor shaft 116 of the rotating electric machine 30 and a propeller rotation shaft 28X provided on the propeller 28. The plurality of gears reduce the rotation speed of the rotor shaft 116 and transmit it to the propeller rotation shaft 28X. Note that the gearbox 119 is installed on the top surface of the housing 110, but is not limited to this. For example, the gearbox 119 may be installed inside the housing 110.

[0020] The rotor shaft 116 is hollow. More specifically, a hollow portion 116H is formed in the rotor shaft 116, extending from the lower end of the rotor shaft 116 along the central axis of the rotor shaft 116. The lower end of the rotor shaft 116 is an open end where the hollow portion 116H opens. The upper end of the rotor shaft 116 is a closed end where the hollow portion 116H does not open.

[0021] The cooling device 32 is a device that cools the rotating electrical machine 30. The cooling device 32 has a tubular member 120, a refrigerant flow path 122, a liquid delivery section 124, and a heat dissipation section 126.

[0022] The tubular member 120 is formed in a cylindrical shape, but is not limited to this. The tubular member 120 has an internal cavity 120H. The internal cavity 120H penetrates the tubular member 120 along the direction in which the tubular member 120 extends.

[0023] The tubular member 120 is fixed to a frame or the like of the accommodating section 26 (see FIG. 1) located outside the housing 110. The tubular member 120 passes through the housing 110, and a portion of the tubular member 120 is inserted into the hollow section 116H of the rotor shaft 116. The tubular member 120 does not rotate even when the rotor shaft 116 rotates.

[0024] The distal end E1 of the tubular member 120 is the upper end of the tubular member 120 and opens into the hollow portion 116H of the rotor shaft 116. The distal end E1 of the tubular member 120 is located near the top surface F1 of the hollow portion 116H. More specifically, the distal end E1 of the tubular member 120 is located between the top surface F1 of the hollow portion 116H and a portion of the hollow portion 116H that is located inside the rotor 114. The proximal end E2 of the tubular member 120 is the lower end of the tubular member 120 and is located outside the housing 110.

[0025] The inner diameter of the tubular member 120 at the distal end E1 of the tubular member 120 is larger than the inner diameter of the tubular member 120 at the proximal end E2 of the tubular member 120. In other words, the cross-sectional area of ​​the internal cavity 120H at the distal end E1 of the tubular member 120 is larger than the cross-sectional area of ​​the internal cavity 120H at the proximal end E2 of the tubular member 120. In this embodiment, the inner diameter of the tubular member 120 (cross-sectional area of ​​the internal cavity 120H) increases from the proximal end E2 to the distal end E1 of the tubular member 120, but is not limited thereto. For example, the inner diameter of the tubular member 120 (cross-sectional area of ​​the internal cavity 120H) may increase from an intermediate position between the proximal end E2 and the distal end E1 of the tubular member 120 toward the distal end E1. In this case, the inner diameter (cross-sectional area of ​​the internal cavity 120H) from the proximal end E2 to the intermediate position of the tubular member 120 is constant.

[0026] The refrigerant flow path 122 is formed so that the refrigerant circulates between the rotating electrical machine 30 and the heat dissipation section 126. The refrigerant flow path 122 includes a first partial flow path 122A, a second partial flow path 122B, a third partial flow path 122C, and a fourth partial flow path 122D.

[0027] The first partial flow path 122A is a portion of the refrigerant flow path 122 that is located between the inner circumferential surface F10 of the rotor shaft 116 and the outer circumferential surface F20 of the tubular member 120. The first partial flow path 122A is formed by a gap between the inner circumferential surface F10 of the rotor shaft 116 and the outer circumferential surface F20 of the tubular member 120.

[0028] The second partial flow path 122B is a portion of the refrigerant flow path 122 that is located in the tubular member 120. The second partial flow path 122B is formed by an internal cavity 120H of the tubular member 120.

[0029] The third partial flow path 122C is a portion that connects the second partial flow path 122B and the heat dissipation unit 126. One end of the third partial flow path 122C is connected to the internal cavity 120H at the base end E2 of the tubular member 120. The other end of the third partial flow path 122C is connected to one end of a pipe provided in the heat dissipation unit 126.

[0030] The fourth partial flow path 122D connects the first partial flow path 122A and the heat dissipation unit 126 via the lower end of the rotor shaft 116. One end of the fourth partial flow path 122D is connected to the first partial flow path 122A. The other end of the fourth partial flow path 122D is connected to the other end of a pipe provided in the heat dissipation unit 126.

[0031] The liquid delivery section 124 is a section for delivering the refrigerant. The liquid delivery section 124 has a liquid delivery rotor 130 that rotates integrally with the rotor shaft 116 to deliver the refrigerant. The liquid delivery rotor 130 is disposed in the first partial flow path 122A and extends spirally in the direction in which the rotor shaft 116 extends. A portion of the liquid delivery rotor 130 is fixed to the inner circumferential surface F10 of the rotor shaft 116. The liquid delivery rotor 130 and the outer circumferential surface F20 of the tubular member 120 are separated by a small gap.

[0032] The heat dissipation unit 126 is a part that dissipates heat from the refrigerant to the outside. The heat dissipation unit 126 may be a radiator. The refrigerant is used to cool the rotating electrical machine 30. The refrigerant may be a liquid such as a coolant or oil, but is not limited to a liquid.

[0033] FIG. 3 is a diagram showing the flow of the refrigerant when the rotary electric machine 30 according to the first embodiment rotates in the first rotation direction D1.

[0034] When the rotor 114 of the rotating electric machine 30 rotates in the first rotation direction D1, the rotor shaft 116 to which the rotor 114 is fixed rotates in the first rotation direction D1. The rotor shaft 116 is connected to the propeller rotation shaft 28X via a gear in the gearbox 119. Therefore, in response to the rotation of the rotor shaft 116, the propeller 28 rotates in the first rotation direction D1.

[0035] Furthermore, a portion of the liquid feed rotator 130 is fixed to the rotor shaft 116. Therefore, in response to the rotation of the rotor shaft 116, the liquid feed rotator 130 rotates in the first rotation direction D1 in the first partial flow path 122A. When the liquid feed rotator 130 rotates in the first rotation direction D1, the refrigerant in the first partial flow path 122A flows upward. The upward direction is the direction from the base end E2 of the tubular member 120 to the tip E1 of the tubular member 120. The refrigerant flowing upward through the first partial flow path 122A flows from the tip E1 of the tubular member 120 into the internal cavity 120H (second partial flow path 122B) of the tubular member 120. The refrigerant that has flowed into the second partial flow path 122B flows downward through the second partial flow path 122B. The downward direction is the direction from the tip E1 of the tubular member 120 to the base end E2 of the tubular member 120. The refrigerant flowing downward through the second partial flow path 122B flows into the third partial flow path 122C and reaches the heat dissipation section 126. The refrigerant that has reached the heat dissipation section 126 flows into the first partial flow path 122A from the lower end of the rotor shaft 116 via the fourth partial flow path 122D. In this manner, the refrigerant circulates between the rotating electrical machine 30 and the heat dissipation section 126.

[0036] FIG. 4 is a diagram showing the flow of the refrigerant when the rotary electric machine 30 according to the first embodiment rotates in the second rotation direction D2.

[0037] When the rotor 114 of the rotating electric machine 30 rotates in the second rotation direction D2, the rotor shaft 116 to which the rotor 114 is fixed rotates in the second rotation direction D2. In response to the rotation of the rotor shaft 116, the propeller 28 rotates in the second rotation direction D2.

[0038] Furthermore, in response to the rotation of the rotor shaft 116, the liquid supply rotator 130 rotates in the second rotation direction D2 in the first partial flow path 122A. When the liquid supply rotator 130 rotates in the second rotation direction D2, the refrigerant in the first partial flow path 122A flows downward. The refrigerant flowing downward in the first partial flow path 122A reaches the heat dissipation section 126 via the fourth partial flow path 122D. The refrigerant that has reached the heat dissipation section 126 flows into the second partial flow path 122B (internal cavity 120H) from the base end E2 of the tubular member 120 via the third partial flow path 122C. The refrigerant that has flowed into the second partial flow path 122B flows upward through the second partial flow path 122B and flows out from the tip E1 of the tubular member 120 into the hollow portion 116H of the rotor shaft 116. The refrigerant that has flowed out into the hollow portion 116H flows into the first partial flow path 122A. In this manner, the coolant circulates between the rotating electrical machine 30 and the heat dissipation section 126 .

[0039] The rotating electric machine 30 generates heat in response to the rotation of the rotor 114 in the first rotation direction D1 or the second rotation direction D2. In particular, the amount of heat generated by the rotor 114 is greater than that of the other portions of the rotating electric machine 30. The heat generated by the rotor 114 is absorbed by the refrigerant flowing through the first partial flow path 122A, which is the portion of the refrigerant flow path 122 closest to the rotor 114. This cools the rotor 114. The refrigerant that has absorbed the heat is dissipated in the heat dissipation section 126 and then returned to the first partial flow path 122A.

[0040] 3, when the rotor 114 rotates in the first rotation direction D1, in the rotary electric machine 30, the refrigerant from which heat has been dissipated by the heat dissipation portion 126 first flows through the first partial flow path 122A. Thereafter, the refrigerant flows through the second partial flow path 122B (the internal cavity 120H of the tubular member 120).

[0041] 4, when the rotor 114 rotates in the second rotation direction D2, in the rotary electric machine 30, the refrigerant whose heat has been dissipated by the heat dissipation portion 126 first flows through the second partial flow path 122B (the internal cavity 120H of the tubular member 120). Thereafter, the refrigerant flows through the first partial flow path 122A.

[0042] As described above, when the rotor 114 rotates in the first rotation direction D1, the refrigerant whose heat has been dissipated by the heat dissipation portion 126 immediately reaches the first partial flow path 122A. On the other hand, when the rotor 114 rotates in the second rotation direction D2, the refrigerant whose heat has been dissipated by the heat dissipation portion 126 absorbs heat in the second partial flow path 122B and then reaches the first partial flow path 122A. For this reason, when a simple tubular member with a constant inner diameter is used, the cooling efficiency of the rotor 114 when the rotor 114 rotates in the second rotation direction D2 is lower than the cooling efficiency of the rotor 114 when the rotor 114 rotates in the first rotation direction D1.

[0043] In contrast to this, in this embodiment, the cross-sectional area of ​​the second partial flow path 122B formed by the internal cavity 120H of the tubular member 120 is not constant along the extension direction of the tubular member 120. That is, the cross-sectional area of ​​the second partial flow path 122B at the tip end E1 of the tubular member 120 is larger than the cross-sectional area of ​​the second partial flow path 122B at the base end E2 of the tubular member 120.

[0044] As a result, the flow rate of the refrigerant flowing through the internal cavity 120H of the tubular member 120 from the base end E2 to the tip end E1 is faster than the flow rate of the refrigerant flowing through the internal cavity 120H from the tip end E1 to the base end E2. This prevents the refrigerant from being heated in the second partial flow path 122B before reaching the first partial flow path 122A. Because the refrigerant is prevented from being heated in the first partial flow path 122A before reaching the second partial flow path 122B, it is possible to reduce the difference between the cooling efficiency of the rotor 114 when the rotor 114 rotates in the second rotational direction D2 and the cooling efficiency of the rotor 114 when the rotor 114 rotates in the first rotational direction D1.

[0045] In this embodiment, the first cooling performance and the second cooling performance are approximately the same at the rated output of the rotating electric machine 30. The first cooling performance is the cooling performance for the rotor 114 when the rotor 114 rotates in the first rotation direction D1. The second cooling performance is the cooling performance for the rotor 114 when the rotor 114 rotates in the second rotation direction D2. In this embodiment, the inner diameter of the tubular member 120 from the base end E2 to the tip end E1 of the tubular member 120 (the cross-sectional area of ​​the internal cavity 120H) is set so that the first cooling performance and the second cooling performance are approximately the same at the rated output of the rotating electric machine 30.

[0046] Furthermore, in this embodiment, the liquid-sending rotor 130 disposed in the first partial flow path 122A rotates integrally with the rotor shaft 116. That is, the refrigerant can be circulated through the refrigerant flow path 122 by utilizing the power for rotating the propeller 28. Furthermore, since the liquid-sending rotor 130 is provided, a pump or the like for circulating the refrigerant is not required. Therefore, according to this embodiment, the number of parts can be reduced and the rotating electric machine 30 can be well cooled with a simple configuration.

[0047] (Second embodiment) In the second embodiment, explanations that overlap with those in the first embodiment will be omitted. Fig. 5 is a diagram showing the configuration of a rotating electric machine 30 and a cooling device 32 according to the second embodiment. In Fig. 5, the same components as those described in the first embodiment are denoted by the same reference numerals.

[0048] In this embodiment, the proximal end E2 of the tubular member 120 is located inside the housing 110 and is fixed to the inner wall of the housing 110.

[0049] In this embodiment, openings 120A are formed in the side surface of the tubular member 120. The openings 120A are formed in a portion of the tubular member 120 that is located outside the rotor shaft 116. In other words, the openings 120A are located between the base end E2 of the tubular member 120 and the lower end of the rotor shaft 116. There may be one opening 120A. Alternatively, there may be multiple openings 120A. In this case, the openings 120A are formed at intervals along the circumferential direction of the rotor shaft 116.

[0050] In this embodiment, the third partial flow path 122C includes a first flow path space 132, a shaft opening 134, and a first connection port 136. The first flow path space 132 is a space surrounded by a first partition wall 138, a second partition wall 140, the side wall of the housing 110, and the rotor shaft 116. The first flow path space 132 communicates with the first partial flow path 122A via the shaft opening 134.

[0051] The first partition wall 138 is located higher than the second partition wall 140. The second partition wall 140 is located higher than the lower end of the rotor shaft 116. The first partition wall 138 and the second partition wall 140 each extend from the inner wall of the housing 110 toward the outer circumferential surface (outer wall) of the rotor shaft 116. Bearings 118 are provided between the inner edge (tip) of the first partition wall 138 and the rotor shaft 116, and between the inner edge (tip) of the second partition wall 140 and the rotor shaft 116.

[0052] The shaft opening 134 is formed in a portion of the rotor shaft 116 that is located between the first partition wall portion 138 and the second partition wall portion 140. The shaft opening 134 is a through-hole that penetrates the rotor shaft 116. There may be one shaft opening 134. Alternatively, there may be multiple shaft openings 134. In this case, the shaft openings 134 are formed at intervals along the circumferential direction of the rotor shaft 116.

[0053] The first connection port 136 is a port for introducing and discharging the refrigerant into and from the housing 110. The first connection port 136 is located between the first partition wall portion 138 and the second partition wall portion 140. The first connection port 136 is connected to the pump 142 via a pipe, and the pump 142 and the first flow path space 132 are in communication with each other.

[0054] In this embodiment, the fourth partial flow path 122D includes a second flow path space 144, an opening 120A, and a second connection port 146. The second flow path space 144 is a space surrounded by the second partition wall portion 140, the side wall of the housing 110, and the bottom wall of the housing 110. The second flow path space 144 communicates with the second partial flow path 122B via the opening 120A.

[0055] The second connection port 146 is a port for introducing and discharging the refrigerant into and from the housing 110. The second connection port 146 is located below the first connection port 136. The second connection port 146 is connected to the heat dissipation portion 126 via a pipe, and the heat dissipation portion 126 and the second flow path space 144 are in communication with each other.

[0056] In this embodiment, the liquid delivery unit 124 has a pump 142 instead of the liquid delivery rotor 130. The pump 142 is provided outside the housing 110. As described above, the pump 142 is connected to the first connection port 136 via a pipe. The pump 142 is also connected to the heat dissipation unit 126 via a pipe. The pump 142 has a pump shaft 148. The pump 142 draws in refrigerant by the rotational motion of the pump shaft 148 and delivers the drawn refrigerant.

[0057] The pump shaft 148 is coupled to the propeller rotation shaft 28X via a power transmission member 150. The power transmission member 150 is a chain, but is not limited to this. For example, the power transmission member 150 may be a belt or a gear. The pump shaft 148 rotates in conjunction with the rotation of the propeller rotation shaft 28X. The pump shaft 148 rotates in a first rotation direction D1 in response to the rotation of the propeller rotation shaft 28X in the first rotation direction D1. On the other hand, the pump shaft 148 rotates in a second rotation direction D2 in response to the rotation of the propeller rotation shaft 28X in the second rotation direction D2.

[0058] FIG. 6 is a diagram showing the flow of the refrigerant when the rotary electric machine 30 according to the second embodiment rotates in the first rotation direction D1.

[0059] When the rotor shaft 116 rotates in the first rotation direction D1, the propeller 28 rotates in the first rotation direction D1. A propeller rotation shaft 28X of the propeller 28 is connected to the pump shaft 148 via a power transmission member 150. Therefore, in response to the rotation of the propeller rotation shaft 28X, the pump shaft 148 rotates in the first rotation direction D1.

[0060] When the pump shaft 148 rotates in the first rotation direction D1, the pump 142 sends the refrigerant to the first flow path space 132 via the first connection port 136. The refrigerant sent to the first flow path space 132 flows into the first partial flow path 122A via the shaft opening 134 and flows upward through the first partial flow path 122A. The refrigerant flowing upward through the first partial flow path 122A flows into the second partial flow path 122B from the tip E1 of the tubular member 120 and flows downward through the second partial flow path 122B. The refrigerant flowing downward through the second partial flow path 122B flows out into the second flow path space 144 via the opening 120A and reaches the heat dissipation unit 126 via the second connection port 146. The refrigerant that has reached the heat dissipation unit 126 is sent to the first flow path space 132 by the pump 142. In this manner, the refrigerant circulates between the rotating electric machine 30 and the heat dissipation unit 126.

[0061] FIG. 7 is a diagram showing the flow of the refrigerant when the rotary electric machine 30 according to the second embodiment rotates in the second rotation direction D2.

[0062] When the rotor shaft 116 rotates in the second rotation direction D2, the propeller 28 rotates in the second rotation direction D2. A propeller rotation shaft 28X of the propeller 28 is connected to the pump shaft 148 via a power transmission member 150. Therefore, in response to the rotation of the propeller rotation shaft 28X, the pump shaft 148 rotates in the second rotation direction D2.

[0063] When the pump shaft 148 rotates in the second rotation direction D2, the pump 142 sends the refrigerant to the heat dissipation unit 126. The refrigerant sent to the heat dissipation unit 126 flows into the second flow path space 144 via the second connection port 146. The refrigerant that flows into the second flow path space 144 flows into the second partial flow path 122B via the opening 120A and flows upward through the second partial flow path 122B. The refrigerant flowing upward through the second partial flow path 122B flows into the first partial flow path 122A from the tip E1 of the tubular member 120 and flows downward through the first partial flow path 122A. The refrigerant flowing downward through the first partial flow path 122A flows out into the first flow path space 132 via the shaft opening 134 and reaches the pump 142 via the first connection port 136. The refrigerant that reaches the pump 142 is sent to the heat dissipation unit 126 by the pump 142. In this manner, the coolant circulates between the rotating electrical machine 30 and the heat dissipation section 126 .

[0064] In this embodiment, the propeller rotation shaft 28X of the propeller 28, which rotates in conjunction with the rotor shaft 116, is connected to the pump shaft 148 of the pump 142 via a power transmission member 150. Therefore, the pump 142 sends the refrigerant to the refrigerant flow path 122 by the rotational force of the rotor shaft 116. This allows the refrigerant to circulate through the refrigerant flow path 122 without providing a separate drive source for the pump 142. As a result, the rotating electric machine 30 can be cooled with a simple configuration.

[0065] As described above, in the above embodiment, the cross-sectional area of ​​the second partial flow channel 122B at the tip E1 of the tubular member 120 is larger than the cross-sectional area of ​​the second partial flow channel 122B at the base end E2 of the tubular member 120.

[0066] As a result, the flow rate of the refrigerant flowing through the internal cavity 120H of the tubular member 120 from the base end E2 to the tip end E1 is faster than the flow rate of the refrigerant flowing through the internal cavity 120H from the tip end E1 to the base end E2. When the refrigerant flows through the internal cavity 120H from the base end E2 to the tip end E1, the flow rate of the refrigerant flowing through the internal cavity 120H is relatively fast, which prevents the refrigerant from being heated in the second partial flow path 122B before reaching the first partial flow path 122A. Since the refrigerant is prevented from being heated in the first partial flow path 122A before reaching the second partial flow path 122B, the difference between the cooling efficiency of the rotor 114 when the rotor 114 rotates in the second rotation direction D2 and the cooling efficiency of the rotor 114 when the rotor 114 rotates in the first rotation direction D1 can be reduced. Therefore, the tubular member 120 can be used in common regardless of the rotation direction of the propeller 28. As a result, the number of parts can be reduced and good cooling can be achieved with a simple configuration.

[0067] The following additional notes are further disclosed regarding the above embodiment.

[0068] (Appendix 1) The cooling device (32) of the present disclosure is a cooling device for cooling a rotating electric machine (30) including a stator (112), a rotor (114), and a rotor shaft (116) that rotates integrally with the rotor, and includes: a tubular member (120) inserted into the hollow rotor shaft; and a liquid delivery section (124) that circulates a refrigerant through a refrigerant flow path (122) that includes a first partial flow path (122A) located between an inner circumferential surface (F10) of the rotor shaft and an outer circumferential surface (F20) of the tubular member; and a second partial flow path (122B) formed by an internal cavity (120H) of the tubular member, wherein the first partial flow path and the second partial flow path are connected to each other at a tip (E1) of the tubular member, and the flow path cross-sectional area of ​​the second partial flow path at the tip of the tubular member is larger than the flow path cross-sectional area of ​​the second partial flow path at a base end (E2) of the tubular member.

[0069] (Appendix 2) In the cooling device according to Supplementary Note 1, a flow path cross-sectional area of ​​the second partial flow path may increase from the base end toward the tip end.

[0070] (Appendix 3) In the cooling device described in Appendix 1, the liquid delivery unit may circulate the refrigerant through the refrigerant flow path so that the refrigerant passing through the first partial flow path reaches the second partial flow path in response to rotation of the rotor in a first rotation direction (D1), and may circulate the refrigerant through the refrigerant flow path so that the refrigerant passing through the second partial flow path reaches the first partial flow path in response to rotation of the rotor in a second rotation direction (D2) opposite to the first rotation direction.

[0071] (Appendix 4) In the cooling device described in Appendix 3, the cooling performance for the rotor when the rotor rotates in the first rotation direction and the cooling performance for the rotor when the rotor rotates in the second rotation direction may be approximately the same at the rated output of the rotating electric machine.

[0072] (Appendix 5) In the cooling device according to Supplementary Note 1, the liquid delivery section may have a liquid delivery rotor (130) disposed in the first partial flow path and rotating integrally with the rotor shaft.

[0073] (Appendix 6) In the cooling device according to Supplementary Note 5, the liquid-feeding rotor may extend spirally in the direction in which the rotor shaft extends.

[0074] (Appendix 7) In the cooling device according to Supplementary Note 1, the liquid delivery unit may include a pump (142) that delivers the refrigerant to the refrigerant flow path by a rotational force of the rotor shaft.

[0075] (Appendix 8) The aircraft (10) of the present disclosure includes the cooling device described in any one of Supplementary Notes 1 to 7 and the rotating electric machine.

[0076] (Appendix 9) In the aircraft according to Supplementary Note 8, the plurality of rotating electric machines may each be provided with the cooling device having the same structure.

[0077] (Appendix 10) The aircraft according to Supplementary Note 9 may include two or more propellers (28) rotating in different directions.

[0078] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments. [Explanation of symbols]

[0079] 10...Flying object 30...Rotating electric machine 32...cooling device 110...housing 112... Stator 114... Rotor 116... rotor shaft 118... bearing 120... Tubular member 122... Refrigerant flow path 122A...First partial flow path 122B...Second partial flow path 122C...Third partial flow path 122D...Fourth partial flow path 124...liquid delivery section 126...heat dissipation section 130...liquid-transport rotor 132...first flow path space 134... Shaft opening 136... First connection port 138...First partition part 140...Second partition part 142... Pump 144... Second flow path space 146...Second connection port 148...Pump shaft 150...Power transmission member

Claims

1. A cooling device for cooling a rotating electric machine including a stator, a rotor, and a rotor shaft that rotates integrally with the rotor, a tubular member inserted into the hollow rotor shaft; a liquid delivery unit that circulates a refrigerant through a refrigerant flow path that includes a first partial flow path located between an inner circumferential surface of the rotor shaft and an outer circumferential surface of the tubular member, and a second partial flow path formed by an internal cavity of the tubular member; Equipped with the first partial flow path and the second partial flow path communicate with each other at a tip end of the tubular member, A cooling device, wherein a cross-sectional area of ​​the second partial flow passage at the distal end of the tubular member is greater than a cross-sectional area of ​​the second partial flow passage at the proximal end of the tubular member.

2. 2. The cooling device according to claim 1, A cooling device, wherein the cross-sectional area of ​​the second partial flow path increases from the base end to the tip end.

3. 2. The cooling device according to claim 1, The liquid delivery unit is The refrigerant is caused to flow through the refrigerant flow path so that the refrigerant passing through the first partial flow path reaches the second partial flow path in response to rotation of the rotor in a first rotation direction; a cooling device that circulates the refrigerant through the refrigerant flow path such that the refrigerant passing through the second partial flow path reaches the first partial flow path in response to rotation of the rotor in a second rotation direction opposite to the first rotation direction.

4. The cooling device according to claim 3, A cooling device in which the cooling performance for the rotor when the rotor rotates in the first rotational direction and the cooling performance for the rotor when the rotor rotates in the second rotational direction are approximately the same at the rated output of the rotating electric machine.

5. 2. The cooling device according to claim 1, The liquid delivery section is disposed in the first partial flow path and has a liquid delivery rotor that rotates integrally with the rotor shaft.

6. 6. The cooling device according to claim 5, The cooling device, wherein the liquid-feeding rotor extends spirally in the direction in which the rotor shaft extends.

7. 2. The cooling device according to claim 1, The cooling device, wherein the liquid delivery unit has a pump that delivers the refrigerant to the refrigerant flow path by the rotational force of the rotor shaft.

8. An aircraft comprising: the cooling device according to any one of claims 1 to 7; and the rotating electric machine.

9. The flying vehicle according to claim 8, The aircraft is provided with the cooling device having the same structure for each of the plurality of rotating electric machines.

10. The flying vehicle according to claim 9, An aircraft equipped with two or more propellers that rotate in different directions.

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