Electric drive device

Abstract

To provide an electric drive device equipped with an electric motor and a transmission mechanism that can achieve both cooling and miniaturization of the electric motor and transmission mechanism. [Solution] The electric drive device 10 includes an electric motor 32 having a drive unit 61 that drives a rotating shaft 31, and a transmission mechanism 33 connected to one end of the rotating shaft 31 and the drive shaft, which transmits output torque. A first helical passage 81 and a second helical passage 90 are formed in the rotating shaft 31. The first helical passage 81 has a first inlet 81A formed between the transmission mechanism 33 and the drive unit 61, and a first outlet 81B formed on the other end, and sends the lubricating oil L that flows into the first inlet 81A to the first outlet 81B. The second helical passage 90 has a second inlet 90A formed on the other end of the rotating shaft 31, and a second outlet 90B formed on a connection part 87 connected to the transmission mechanism 33, and sends the lubricating oil L that flows into the second inlet 90A to the second outlet 90B.

Description

[Technical Field]

[0001] The present invention relates to an electric drive device comprising an electric motor that drives a rotating shaft, a drive shaft, and a transmission mechanism that transmits output torque of the electric motor from the rotating shaft to the drive shaft. [Background Art]

[0002] In recent years, efforts toward realizing a low-carbon society or a carbon-neutral society have intensified, and research and development on electrification technology has been carried out also in vehicles, aircraft and the like to reduce CO₂ emissions and improve energy efficiency.

[0003] In aircraft, an electric drive device having an electric motor and a transmission mechanism (a speed reducer) is used to rotate a propeller. There is a demand for size reduction of the electric drive device. On the other hand, in an electric drive device, since the electric motor and the transmission mechanism generate heat, the electric drive device needs to be cooled. When a cooling device is provided in the electric drive device, the cooling device increases the size of the electric drive device. Accordingly, there exists a technology for cooling the electric drive device while suppressing an increase in size of the electric drive device. For example, Patent Document 1 describes a thrust generating device including a speed reducer of a planetary gear mechanism and an electric motor connected to the planetary gear mechanism. A rotating shaft of the planetary gear mechanism is provided with a spiral groove that functions as a pump, and lubricating oil is stored inside a case of the planetary gear mechanism. Then, the lubricating oil is conveyed by the spiral groove of the rotating shaft, and the lubricating oil circulates inside the planetary gear mechanism. This makes it possible to cool the electric drive device while suppressing an increase in size of the electric drive device. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 2024-126692 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] By the way, the thrust generating device described in Patent Document 1 does not mention cooling the electric motor.

[0006] In view of the above background, the present invention aims to provide an electric drive device that includes an electric motor and a transmission mechanism, and that can achieve both cooling and miniaturization of the electric motor and the transmission mechanism. This will ultimately contribute to improving energy efficiency. [Means for solving the problem]

[0007] To solve the above problems, one aspect of the present invention provides an electric drive device comprising: an electric motor having a rotating shaft and a drive unit for driving the rotating shaft; a drive shaft; a transmission mechanism connected to one end of the rotating shaft and the drive shaft, which transmits the output torque of the electric motor from the rotating shaft to the drive shaft, the device comprising: a case; a lubrication oil passage provided in the case through which lubricating oil flows, wherein the rotating shaft is formed in a hollow cylindrical shape extending in the axial direction of the rotating shaft, and has a first shaft portion coupled to the drive unit at the other end of the rotating shaft beyond the transmission mechanism; and a second shaft portion inserted inside the first shaft portion, arranged coaxially with the first shaft portion, having a connecting portion connected to the transmission mechanism at one end, and rotating together with the first shaft portion, and the lubrication The oil passage includes a first helical passage formed in the first shaft portion and extending spirally around the rotation axis of the rotating shaft, and a second helical passage formed in the second shaft portion and extending spirally around the rotation axis of the rotating shaft, wherein the first helical passage has a first inlet formed between the transmission mechanism and the drive unit in the first shaft portion and a first outlet formed on the other end side, and is configured to send the lubricating oil that flows into the first inlet due to the rotation of the first shaft portion to the first outlet, and the second helical passage has a second inlet formed on the other end side of the rotating shaft and a second outlet formed in the connection portion, and is configured to send the lubricating oil that flows into the second inlet due to the rotation of the second shaft portion to the second outlet.

[0008] In this embodiment, the second outlet of the second helical passage is provided at the connection point connected to the transmission mechanism. Therefore, the transmission mechanism can be lubricated and cooled by the lubricating oil flowing out from the second outlet. Furthermore, since the first helical passage is formed on the first shaft portion of the rotating shaft coupled to the drive unit of the electric motor, the heat transmitted from the drive unit of the electric motor to the first shaft portion is cooled by the lubricating oil flowing through the first helical passage. In this way, the lubricating oil flowing through the first helical passage can cool the drive unit of the electric motor. Moreover, since the first and second helical passages are formed on the rotating shaft, the lubricating oil passages can be made smaller. As a result, the electric drive device can lubricate the transmission mechanism and cool the electric motor with a miniaturized lubricating oil passage. Thus, the electric drive device, equipped with an electric motor and a transmission mechanism, can achieve both cooling of the electric motor and transmission mechanism and miniaturization. [Effects of the Invention]

[0009] According to the above embodiments, it is possible to provide an electric drive device that includes an electric motor and a transmission mechanism, and that can achieve both cooling and miniaturization of the electric motor and the transmission mechanism. [Brief explanation of the drawing]

[0010] [Figure 1] Perspective view of an aircraft according to the embodiment [Figure 2] Perspective view of the base and electric drive unit [Figure 3] Cross-sectional view of an electric drive device [Figure 4] Perspective view of the bottom wall of the case [Figure 5] Perspective view of the axis of rotation [Figure 6] Exploded perspective view of the rotation axis [Figure 7] Figure 3, section VII-VII [Figure 8] Figure 3, section VIII-VIII [Figure 9] Figure 3, section IX-IX [Figure 10] Cross-sectional view of XX in Figure 3 [Figure 11] Cross-sectional view of the transmission mechanism MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, an aircraft 1 according to an embodiment of the present invention will be described with reference to the drawings. In the drawings and the following description, front-rear, left-right, and up-down directions are defined with reference to the aircraft 1.

[0012] <Aircraft 1> FIG. 1 is a perspective view showing an aircraft 1 according to an embodiment. As shown in FIG. 1, the aircraft 1 is an electric vertical take-off and landing aircraft (eVTOL) capable of vertical take-off and landing. The aircraft 1 includes a fuselage 2 extending in the front-rear direction, a front wing 3 extending in the left-right direction and connected to a front portion of the fuselage 2, a rear wing 4 extending in the left-right direction and connected to a rear portion of the fuselage 2, a left arm 5L extending in the front-rear direction and connecting a left end portion of the front wing 3 and a left side portion of the rear wing 4, and a right arm 5R extending in the front-rear direction and connecting a right end portion of the front wing 3 and a right side portion of the rear wing 4. The front wing 3 and the rear wing 4 are formed in a shape that generates lift for forward movement.

[0013] A cabin (not shown) for occupants to board is provided at a front portion of the fuselage 2. Left and right rear thrust generators 7 that cause the aircraft 1 to generate forward propulsive force are provided at a rear end portion of the fuselage 2.

[0014] A plurality of (for example, four) electric drive devices 10 are provided on each of the left arm 5L and the right arm 5R at intervals in the front-rear direction. Each electric drive device 10 causes the aircraft 1 to generate ascending force and descending force. A plurality of bases 11 to which the plurality of electric drive devices 10 are respectively attached are provided on the left arm 5L and the right arm 5R.

[0015] Each base 11 has the same configuration. Also, each electric drive device 10 has the same configuration. Hereinafter, one electric drive device 10 will be described.

[0016] Figure 2 is a perspective view of a base 11 and an electric drive device 10. As shown in Figure 2, the base 11 is provided on the left arm 5L and the right arm 5R, and is formed in a plate shape. The base 11 has a mounting hole 12 penetrating in the up-down direction. The mounting hole 12 is a circular hole. A support portion 14 is detachably attached to the base 11. The electric drive device 10 is attached to the base 11 via the support portion 14.

[0017] Each electric drive device 10 includes a case 15, and a drive shaft 17 having a propeller 16 fixed to an upper end (one end) side and extending in the up-down direction.

[0018] The support portion 14 has a cylindrical main body portion 21 that rotatably supports the drive shaft 17, and four arm portions 22 extending radially outward from the main body portion 21. The main body portion 21 is formed in a cylindrical shape extending in the up-down direction. A bearing hole 23 penetrating vertically is provided in the center of the main body portion 21. A bearing (not shown) is provided in the bearing hole 23. The drive shaft 17 is rotatably supported in the bearing hole 23 via the bearing.

[0019] The four arm portions 22 extend radially from the lower end of the main body portion 21. Each arm portion 22 is coupled to the main body portion 21. Each arm portion 22 is fastened to the base 11 by a fastener 24 such as a bolt and a nut. Accordingly, the main body portion 21 is supported by the base 11 via the plurality of arm portions 22. Further, each arm portion 22 is fastened to the case 15 by a fastener 25 such as a bolt and a nut. Thereby, the electric drive device 10 is fixed to the base 11 via the arm portion 22. Each electric drive device 10 rotates the propeller 16 together with the drive shaft 17 to generate a lifting force and a lowering force in the aircraft 1.

[0020] <Electric drive device 10> Figure 3 is a schematic cross-sectional view of the electric drive device 10. As shown in Figure 3, the electric drive device 10 includes a case 15, an electric motor 32 having a drive shaft 17 extending vertically and a rotating shaft 31, with a propeller 16 (not shown in Figure 3) fixed to its upper end (one end), and a transmission mechanism 33 connected to the rotating shaft 31 and the drive shaft 17, which transmits the output torque of the electric motor 32 from the rotating shaft 31 to the drive shaft 17. The drive shaft 17 and the rotating shaft 31 are arranged coaxially. The direction in which the rotation axes of the drive shaft 17 and the rotating shaft 31 extend is defined as the axial direction X. The axial direction X is the vertical direction.

[0021] The case 15 has a cylindrical peripheral wall portion 41 extending in the axial direction X, an upper wall portion 42 connected to the upper end of the peripheral wall portion 41, and a bottom wall portion 43 connected to the lower end of the peripheral wall portion 41. The case 15 houses the electric motor 32 and the transmission mechanism 33. The electric motor 32 is located below the transmission mechanism 33.

[0022] The peripheral wall portion 41 has partition wall portions 46 and 47 formed in a plate shape that protrude radially inward, and a first cooling passage 48 formed inside. A rotating shaft 31 is inserted through partition wall portions 46 and 47.

[0023] The partition wall 46 is positioned between the electric motor 32 and the transmission mechanism 33 and is inclined downward toward the radially inward direction. The upper surface 46A of the partition wall 46 is inclined downward toward the radially inward direction. Below the radially inward end of the partition wall 46, a bearing 51 is provided to rotatably support the rotating shaft 31. The partition wall 46 has a cylindrical wall portion 46B that extends downward on the outer circumference of the bearing 51. The bearing 51 is supported by the lower surface of the radially inward end of the partition wall 46 and the cylindrical wall portion 46B. The bearing 51 is preferably a bearing capable of supporting radial and axial loads. The bearing 51 is preferably, for example, a tapered roller bearing or an angular contact ball bearing.

[0024] The partition wall portion 47 is formed as a plate-like structure that protrudes radially inward below the electric motor 32. There is a gap between the radial inner end of the partition wall portion 47 and the rotating shaft 31.

[0025] The first cooling passage 48 has a spiral passage 48A that extends spirally around the rotation axis of the rotating shaft 31 on the outer circumference of the electric motor 32, an inlet 48B that extends radially outward from the lower end of the spiral passage 48A, and an outlet 48C that extends radially outward from the upper end of the spiral passage 48A. Liquid refrigerant (e.g., water) flows through the first cooling passage 48. The inlet 48B and outlet 48C of the first cooling passage 48 are connected to an external passage 52. The external passage 52 is attached to the case 15. The external passage 52 is equipped with a pump 52A for pressurizing the refrigerant and a heat exchanger 52B. The refrigerant flowing through the first cooling passage 48 is pressurized by the pump 52A and cools the electric motor 32.

[0026] The upper wall portion 42 is formed in a disc shape with its surface facing vertically. The upper wall portion 42 closes the upper opening of the peripheral wall portion 41. The upper wall portion 42 has a through hole 42A that penetrates in the vertical direction. The drive shaft 17 is inserted through the through hole 42A. A bearing capable of supporting radial loads, such as a ball bearing or a sliding bearing, may be provided between the through hole 42A and the drive shaft 17.

[0027] The bottom wall portion 43 is connected to the lower end of the peripheral wall portion 41 and is formed in a conical plate shape that widens upward. The bottom wall portion 43 closes the lower opening of the peripheral wall portion 41. The upper surface of the bottom wall portion 43 includes an inclined surface 43A that slopes downward radially inward.

[0028] Figure 4 is a perspective view of the bottom wall portion 43 of case 15. As shown in Figure 4, the bottom wall portion 43 has a cylindrical wall 56 extending upward on the outer circumference of the rotating shaft 31, a plurality of helical vertical wall portions 57 that extend upward and radially outward from the outer circumference of the rotating shaft 31 in a spiral manner centered on the rotation axis of the rotating shaft 31, and a second cooling passage 58 (see Figure 3) formed inside. The plurality of helical vertical wall portions 57 extend spirally radially outward from the cylindrical wall 56 along the rotation axis.

[0029] A bearing 59 is provided between the cylindrical wall 56 and the lower end of the rotating shaft 31 to support the rotating shaft 31. As shown in Figure 3, the bearing 59 is supported by the inclined surface 43A of the bottom wall 43 and the cylindrical wall 56. The bearing 59 is preferably a bearing capable of supporting radial and axial loads. The bearing 51 is preferably, for example, a tapered roller bearing or an angular contact ball bearing.

[0030] The second cooling passage 58 is located inside the bottom wall 43 and includes a spiral passage 58A that extends spirally from the outer circumference of the rotating shaft 31 radially outward from the axis of rotation of the rotating shaft 31, an inlet 58B extending downward from one end of the spiral passage 58A, and an outlet 58C extending downward from the other end of the spiral passage 58A. Liquid refrigerant (e.g., water) flows through the second cooling passage 58. The inlet 58B and outlet 58C of the second cooling passage 58 are connected to an external passage 60. The external passage 60 is attached to the outside of the case 15. The external passage 60 is equipped with a pump 60A for pressurizing the refrigerant and a heat exchanger 60B. The refrigerant flowing through the second cooling passage 58 cools the bottom wall 43.

[0031] The electric motor 32 has a rotating shaft 31 extending in the axial direction X and a drive unit 61 that drives the rotating shaft 31. The drive unit 61 has a rotor 62 formed integrally with the rotating shaft 31 and a stator 63 that faces the rotor 62 at a distance from it on the outer circumference of the rotor 62.

[0032] The rotor 62 has a cylindrical rotor core 62A extending in the axial direction X, and a plurality of permanent magnets 62B fixed to the outer circumference of the rotor core 62A. The inner surface of the rotor core 62A is coupled to the outer surface of the rotating shaft 31.

[0033] The stator 63 is fixed to the inner surface of the peripheral wall portion 41 and has a plurality of coils (not shown). The magnetic force of the plurality of permanent magnets 62B of the rotor 62 and the magnetic force of the plurality of coils of the stator 63 generate an output torque that rotates the rotor 62 and the rotating shaft 31 around the axis of the rotating shaft 31.

[0034] <Rotation axis 31> Figure 5 is a perspective view of the rotating shaft 31. As shown in Figures 3 and 5, the rotating shaft 31 has a first shaft portion 71 which is formed in a hollow cylindrical shape and extends in the axial direction X, and a second shaft portion 72 which extends in the axial direction X and is inserted inside the first shaft portion 71. The first shaft portion 71 and the second shaft portion 72 are arranged coaxially and connected to each other. The first shaft portion 71 also rotates together with the second shaft portion 72. As shown in Figure 3, the first shaft portion 71 is connected to the rotor 62 (rotor core 62A) of the drive unit 61 on the lower end (other end) side of the rotating shaft 31, relative to the transmission mechanism 33.

[0035] Figure 6 is an exploded perspective view of the rotating shaft 31. As shown in Figures 5 and 6, the first shaft portion 71 includes an inner cylinder portion 76 formed in a hollow cylindrical shape extending in the axial direction X, and an outer cylinder portion 77 formed in a hollow cylindrical shape extending in the axial direction X, with the inner cylinder portion 76 inserted inside. The inner cylinder portion 76 and the outer cylinder portion 77 are connected to each other.

[0036] As shown in Figure 6, the inner cylinder portion 76 has three first helical grooves 76A on its outer surface that extend vertically in a left-handed spiral shape around the rotation axis of the rotating shaft 31. In addition, the inner cylinder portion 76 has three through holes 78 (see Figure 9) that penetrate radially below the first helical grooves 76A.

[0037] The outer cylinder portion 77 has a first outer cylinder portion 77A at its upper end, a shoulder surface 77B extending radially outward from the lower end of the first outer cylinder portion 77A, and a second outer cylinder portion 77C extending downward from the shoulder surface 77B. The outer diameter of the first outer cylinder portion 77A is smaller than the outer diameter of the second outer cylinder portion 77C. As shown in Figure 3, the inner cylinder portion 76 is positioned below the shoulder surface 77B and on the inner circumference of the second outer cylinder portion 77C.

[0038] The second outer cylinder portion 77C is coupled to the rotor 62 (rotor core 62A). As shown in Figures 3 and 6, the upper part of the second outer cylinder portion 77C is provided with three through holes 79 facing the upper ends of the three first helical grooves 76A of the inner cylinder portion 76. The lower part of the second outer cylinder portion 77C is provided with a projection 80 that protrudes radially outward along the entire circumference of the second outer cylinder portion 77C.

[0039] Figure 7 is a cross-sectional view taken along line VII-VII of Figure 3. As shown in Figure 7, each of the three through holes 79 extends tangentially to the upper end of the first helical groove 76A of the inner cylinder portion 76.

[0040] Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 3. As shown in Figures 3 and 8, the protruding portion 80 is provided with an annular groove 80A that recesses radially outward from the inner circumferential surface along its entire circumference, and six through holes 80B (see Figure 7) that extend tangentially outward from the annular groove 80A.

[0041] The annular groove 80A is opposite to the lower end of each of the three first helical grooves 76A. As shown in Figure 8, the six through holes 80B are provided at equal intervals in the circumferential direction of the projection 80 and extend in the tangential direction. Each of the three through holes 80B extends tangentially to the lower end of the first helical groove 76A of the inner cylinder portion 76.

[0042] As shown in Figures 3 and 6, the first shaft portion 71 has a first helical passage 81 through which lubricating oil L flows, formed by three first helical grooves 76A in the inner cylinder portion 76 and three through holes 79, an annular groove 80A, and six through holes 80B in the outer cylinder portion 77.

[0043] The first helical passage 81 extends in a left-handed spiral (either right-handed or left-handed) around the rotation axis of the rotating shaft 31, and extends in the axial direction X. In the first helical passage 81, each of the three through holes 79 of the second outer cylinder portion 77C serves as the first inlet 81A, and the six through holes 80B of the protruding portion 80 serve as the first outlet 81B. The first inlet 81A is formed between the transmission mechanism 33 and the drive unit 61, and the first outlet 81B is formed on the lower end (other end) side of the first shaft portion 71. The first helical passage 81 is formed in a left-handed spiral to send the lubricating oil L that flows into the first inlet 81A due to the rotation of the first shaft portion 71 to the first outlet 81B.

[0044] As shown in Figures 3, 5, and 6, the second shaft portion 72 includes a cylindrical portion 86 formed in a cylindrical shape extending in the axial direction X, and a cylindrical connecting portion 87 connected to the outer circumference of the upper end of the cylindrical portion 86. The cylindrical portion 86 is inserted inside the inner cylinder portion 76 (first shaft portion 71). The cylindrical portion 86 and the inner cylinder portion 76 are connected to each other. In addition, the connecting portion 87 and the outer cylinder portion 77 (upper end of the first outer cylinder portion 77A) are connected to each other.

[0045] As shown in Figure 6, the outer surface of the cylindrical portion 86 is provided with three second helical grooves 86A that extend vertically in a left-handed spiral shape centered on the rotation axis of the rotation shaft 31.

[0046] Figure 9 is a cross-sectional view taken along line IX-IX of Figure 3. As shown in Figure 9, the lower ends of the three second helical grooves 86A face the three through holes 78 of the inner cylinder portion 76. Each of the three through holes 78 of the inner cylinder portion 76 extends tangentially to the lower end of the second helical grooves 86A.

[0047] As shown in Figures 3 and 6, a part of the transmission mechanism 33 (the sun gear 91, which will be described later) is formed on the connection portion 87. As a result, the connection portion 87 is connected to the transmission mechanism 33.

[0048] Figure 10 is a cross-sectional view of XX in Figure 3. As shown in Figures 3 and 10, the connecting portion 87 is provided with an annular groove 87A that is recessed radially outward along its entire circumference, and six through holes 87B that extend radially outward from the annular groove 87A. The annular groove 87A is opposite the upper end of the second helical groove 86A of the cylindrical portion 86. The six through holes 87B are provided at equal intervals in the circumferential direction and extend tangentially. Each of the three through holes 87B extends tangentially to the upper end of the second helical groove 86A of the cylindrical portion 86.

[0049] As shown in Figures 3 and 6, the second shaft portion 72 has a second helical passage 90 through which lubricating oil L flows, formed by three second helical grooves 86A in the cylindrical portion 86 and an annular groove 87A and six through holes 87B in the connecting portion 87.

[0050] The second helical passage 90 extends in a right-handed spiral (the other of right-handed and left-handed) around the rotation axis of the rotating shaft 31, and extends in the axial direction X. In the second helical passage 90, the lower ends of the three second helical grooves 86A of the cylindrical portion 86 serve as the second inlet 90A, and each of the six through holes 87B of the connecting portion 87 serves as the second outlet 90B. In the second shaft portion 72, the second inlet 90A is formed on the lower end (other end) side of the rotating shaft 31. The second outlet 90B is formed in the connecting portion 87. The second helical passage 90 is formed in a right-handed spiral to send the lubricating oil L that flows into the second inlet 90A due to the rotation of the second shaft portion 72 to the second outlet 90B.

[0051] <Transmission mechanism 33> Figure 11 is a perspective view of the transmission mechanism 33. As shown in Figure 11, the transmission mechanism 33 is a planetary gear mechanism having a sun gear 91 provided on the outer circumference of the connection portion 87 of the second shaft portion 72, three planetary gears 92 that mesh with the sun gear 91, a planetary carrier 93 that rotatably supports the three planetary gears 92, and a ring gear 94 that meshes with the three planetary gears 92. There is no limit to the number of planetary gears 92. For example, the number of planetary gears 92 may be four.

[0052] The sun gear 91 is a spur gear coaxial with the rotating shaft 31. The sun gear 91 is integrally formed with the connecting portion 87 of the rotating shaft 31.

[0053] Each planetary gear 92 is a spur gear formed in a cylindrical shape extending in the axial direction X. As shown in Figure 3, each planetary gear 92 has a through hole 92A and an annular upper wall 92B extending radially inward at its upper end. The ring gear 94 is arranged coaxially with the drive shaft 17, the rotating shaft 31, and the sun gear 91. The ring gear 94 is coupled to the inner surface of the peripheral wall portion 41 of the case 15.

[0054] As shown in Figure 11, the planetary carrier 93 is coupled to the drive shaft 17. The planetary carrier 93 has three enlarged diameter plate portions 93A extending radially outward from the drive shaft 17, shaft portions 93B extending downward from each of the three enlarged diameter plate portions 93A, and a bearing 93C (see Figure 3) coupled to the shaft portions 93B. As shown in Figure 3, the shaft portions 93B are inserted through the through hole 92A of the planetary gear 92. The bearing 93C is located below the upper wall 92B of the planetary gear 92. The bearing 93C is coupled to the inner circumferential surface of the through hole 92A of the planetary gear 92 and to the shaft portion 93B. The planetary gear 92 is rotatably supported by the bearing 93C. The bearing 93C is preferably a bearing capable of supporting radial loads. The bearing 93C is preferably a ball bearing or a sliding bearing.

[0055] <Lubricating oil passage 96> The space provided in case 15 through which lubricating oil L flows is referred to as the "lubricating oil passage 96". As shown in Figure 3, the lubricating oil passage 96 includes a first storage space 96A located below the partition wall 47 and on the bottom wall 43 side of case 15, a second storage space 96B located above the partition wall 46, a first spiral passage 81, and a second spiral passage 90.

[0056] The first storage space 96A is connected to the first outlet 81B of the first helical passage 81 and the second inlet 90A of the second helical passage 90, and stores lubricating oil L. The first outlet 81B is located above the oil level OL1 of the lubricating oil L stored in the first storage space 96A. The second inlet 90A is immersed in the lubricating oil L stored in the first storage space 96A.

[0057] The second storage space 96B is connected to the first inlet 81A of the first spiral passage 81 and the second outlet 90B of the second spiral passage 90, and lubricating oil L is stored therein. The upper surface 46A of the partition wall 46 is inclined downward toward the radially inward direction, defining the second storage space 96B. In the second storage space 96B, the upper surface 46A of the partition wall 46 is the bottom surface that is inclined downward toward the radially inward direction.

[0058] <Transmission of driving force by electric drive device 10> As shown in Figure 11, when the motor 32 rotates the rotating shaft 31, the sun gear 91 located on the outer circumference of the rotating shaft 31 rotates. As the sun gear 91 rotates, the three planetary gears 92 that mesh with the sun gear 91 rotate around the axis and revolve around the outer circumference of the sun gear 91. As a result, the planetary carrier 93 rotates together with the drive shaft 17 around the axis of the drive shaft 17. Consequently, the output torque of the rotating shaft 31 is reduced and transmitted to the drive shaft 17. The drive shaft 17 then rotates together with the propeller 16 (see Figure 2), generating an upward or downward force for the aircraft 1.

[0059] <Distribution of lubricating oil L> As detailed below, the lubricating oil L flows through the lubricating oil passage 96 as follows (1) to (4): (1) Inflow of lubricating oil L into the second helical passage 90; as the rotating shaft 31 rotates, the lubricating oil L stored in the first storage space 96A flows into the second inlet 90A of the second helical passage 90. (2) Outflow of lubricating oil L from the second helical passage 90; the lubricating oil L that has flowed into the second inlet 90A is sent to the second outlet 90B by the second helical passage 90, and flows out from the second outlet 90B into the second storage space 96B. The lubricating oil L is then stored in the second storage space 96B. (3) Inflow of lubricating oil L into the first helical passage 81; the lubricating oil L stored in the second storage space 96B flows into the first inlet 81A of the first helical passage 81. (4) Outflow of lubricating oil L from the first spiral passage 81; The lubricating oil L that flows into the first inlet 81A is sent to the first outlet 81B by the first spiral passage 81 and flows out from the first outlet 81B into the first storage space 96A.

[0060] (1) Inflow of lubricating oil L into the second helical passage 90. As shown in Figure 3, the second inlet 90A of the second helical passage 90 is immersed in the lubricating oil L stored in the first storage space 96A. As indicated by the arrow 90in in Figure 9, as the rotating shaft 31 rotates, the lubricating oil L stored in the first storage space 96A flows into the second inlet 90A of the second helical passage 90 formed in the second shaft portion 72. Because the second inlet 90A is immersed in the lubricating oil L stored in the first storage space 96A, the lubricating oil L flows more easily into the second inlet 90A.

[0061] A spiral vertical wall 57 is provided around the second inlet 90A. The spiral vertical wall 57 prevents the lubricating oil L from flowing radially outward from the second inlet 90A. As a result, the spiral vertical wall 57 makes it easier for the lubricating oil L to flow into the second inlet 90A.

[0062] Furthermore, each of the three through holes 78 extends tangentially to the lower end of the second helical groove 86A. As a result, as shown by arrow 90in in Figure 9, the lubricating oil L can flow into the second inlet 90A from the outer circumference of the inner cylinder 76 without significantly changing direction. This makes it easier for the lubricating oil L to flow into the second inlet 90A, and consequently, the flow rate of the lubricating oil L circulating through the second helical passage 90 can be increased.

[0063] (2) Outflow of lubricating oil L from the second helical passage 90. As shown in Figure 3, the second outlet 90B (through hole 87B) of the second helical passage 90 is formed in the connection part 87 connected to the transmission mechanism 33. The second outlet 90B (through hole 87B) is located above the sun gear 91 of the transmission mechanism 33. As shown by the arrow 90out in Figure 10, the lubricating oil L flowing out from the second outlet 90B (through hole 87B) flows towards the part where the sun gear 91 and the planetary gear 92 mesh. This lubricates the part where the sun gear 91 and the planetary gear 92 mesh. The lubricating oil L then adheres to the planetary gear 92. Furthermore, the lubricating oil L is carried to the planetary gear 92 and adheres to the ring gear 94. This lubricates the space between the planetary gear 92 and the ring gear 94. The lubricating oil L that lubricates the transmission mechanism 33 (sun gear 91, planetary gear 92, and ring gear 94) drips from the transmission mechanism 33 and is stored in the second storage space 96B (see Figure 3).

[0064] As shown by the arrow 90out in Figure 10, the lubricating oil L flowing out from each of the upper ends of the three second helical grooves 86A flows through the annular groove 87A and the six through holes 87B, and flows out from the six through holes 87B toward the area where the sun gear 91 and the planetary gear 92 mesh. Here, the number of through holes 87B (6) is greater than the number of second helical grooves 86A (3). By providing the annular groove 87A and the six through holes 87B, the lubricating oil L can be discharged more uniformly in the circumferential direction of the sun gear 91. As a result, the area where the sun gear 91 and the planetary gear 92 mesh is suitably lubricated.

[0065] Furthermore, the second outlet 90B (through hole 87B) extends tangentially to the upper end of the second helical groove 86A. As a result, as shown by the arrow 90out in Figure 10, the lubricating oil L flows out from the second outlet 90B without significantly changing direction from the upper end of the second helical groove 86A. This makes it easier for the lubricating oil L to flow out from the second outlet 90B. Consequently, the flow rate of the lubricating oil L circulating in the second helical passage 90 can be increased.

[0066] (3) Inflow of lubricating oil L into the first helical passage 81. As shown in Figure 3, the first inlet 81A of the first helical passage 81 is connected to the bottom of the second storage space 96B. As indicated by the arrow 81in in Figure 7, the lubricating oil L stored in the second storage space 96B flows into the first helical passage 81 from the first inlet 81A and flows through the first helical passage 81 while falling. As shown in Figures 3 and 6, the first helical passage 81 (first helical groove 76A) is provided on the outer circumference of the rotating shaft 31. As a result, the lubricating oil L flowing through the first helical passage 81 can cool the electric motor 32 from the inside.

[0067] The bottom surface of the second storage space 96B is the upper surface 46A of the partition wall 46, and is inclined downward toward the radially inward direction. This makes it easier for the lubricating oil L to accumulate on the inside of the bottom surface of the second storage space 96B. The lubricating oil L then easily flows into the second inlet 90A located on the inside of the bottom surface of the second storage space 96B.

[0068] Furthermore, as shown in Figure 7, each of the three through holes 79 in the outer cylinder portion 77 extends tangentially to the lower end of the first helical groove 76A. As a result, as indicated by arrow 81in in Figure 7, the lubricating oil L can flow from the outer circumference of the outer cylinder portion 77 into the first helical groove 76A without significantly changing direction. This makes it easier for the lubricating oil L to flow into the first helical passage 81. Therefore, the flow rate of the lubricating oil L circulating in the first helical passage 81 can be increased.

[0069] (4) Outflow of lubricating oil L from the first helical passage 81. The lubricating oil L that has flowed through the first helical passage 81 flows out from the first outlet 81B into the first storage space 96A and is stored in the first storage space 96A. More specifically, as shown by the arrow 81out in Figure 8, the lubricating oil L that has flowed out from each of the lower ends of the three first helical grooves 76A flows through the annular groove 80A and the six through holes 80B, and flows out from the six through holes 80B into the first storage space 96A. As shown in Figure 3, the first outlet 81B is positioned above the oil level OL1 of the lubricating oil L stored in the first storage space 96A. As a result, the lubricating oil L can flow out of the first outlet 81B more easily than if the first outlet 81B were immersed in the lubricating oil L stored in the first storage space 96A.

[0070] Next, the effects of the electric drive device 10 will be explained.

[0071] The first helical passage 81 has a first inlet 81A formed between the transmission mechanism 33 and the drive unit 61, and a first outlet 81B formed on the lower end (other end) side, and is configured to send the lubricating oil L that flows into the first inlet 81A due to the rotation of the first shaft 71 to the first outlet 81B. The second helical passage 90 has a second inlet 90A formed on the lower end (other end) side of the rotating shaft 31, and a second outlet 90B formed on the connecting part 87, and is configured to send the lubricating oil L that flows into the second inlet 90A due to the rotation of the second shaft 72 to the second outlet 90B.

[0072] Here, the second outlet 90B of the second helical passage 90 is provided at the connection part 87 connected to the transmission mechanism 33. Therefore, the transmission mechanism 33 can be lubricated and cooled by the lubricating oil L flowing out from the second outlet 90B. Also, since the first helical passage 81 is formed in the first shaft part 71 coupled to the drive part 61 of the electric motor 32, the heat transferred from the drive part 61 of the electric motor 32 to the first shaft part 71 is cooled by the lubricating oil L flowing through the first helical passage 81. Therefore, the lubricating oil L flowing through the first helical passage 81 can cool the drive part 61 of the electric motor 32. Furthermore, since the first helical passage 81 and the second helical passage 90 are formed in the rotating shaft 31, the lubricating oil passage 96 can be made smaller. As a result, the electric drive device 10 can lubricate the transmission mechanism 33 and cool the electric motor 32 with the miniaturized lubricating oil passage 96. Therefore, the electric drive device 10 includes an electric motor 32 and a transmission mechanism 33, and can achieve both cooling and miniaturization of the electric motor 32 and the transmission mechanism 33.

[0073] Since the second inlet 90A is immersed in the lubricating oil L stored in the first storage space 96A, the lubricating oil L flows easily into the second inlet 90A. This increases the flow rate of the lubricating oil L circulating through the second helical passage 90. As a result, the flow rate of the lubricating oil L that flows out from the second outlet 90B and lubricates the transmission mechanism 33 increases, so that the transmission mechanism 33 can be reliably lubricated with the lubricating oil L.

[0074] The first outlet 81B is positioned above the oil level OL1 of the lubricating oil L stored in the first storage space 96A and is not immersed in the lubricating oil L. As a result, the lubricating oil L flows more easily out of the first outlet 81B of the first helical passage 81 compared to when the first outlet 81B is immersed in the lubricating oil L stored in the first storage space 96A. Consequently, the flow rate of the lubricating oil L flowing through the first helical passage 81 can be increased. As a result, the electric motor 32 can be reliably cooled by the lubricating oil L flowing through the first helical passage 81.

[0075] A second cooling passage 58 (cooling passage) through which refrigerant flows is provided in the bottom wall portion 43 of case 15. The lubricating oil L stored in the first storage space 96A is cooled by the refrigerant flowing through the second cooling passage 58. The lubricating oil L then cools the electric motor 32 and the transmission mechanism 33. Therefore, the electric motor 32 and the transmission mechanism 33 can be cooled more reliably by the lubricating oil L.

[0076] Case 15 includes multiple helical vertical wall sections 57. The helical vertical wall sections 57 are provided around the second inlet 90A. The helical vertical wall sections 57 suppress the radial outward flow of lubricating oil L from the second inlet 90A. This makes it easier for lubricating oil L to flow into the second inlet 90A. Consequently, the flow rate of lubricating oil L circulating through the second helical passage 90 can be increased. As a result, the transmission mechanism 33 can be reliably lubricated and cooled by the lubricating oil L.

[0077] The first inlet 81A is immersed in the lubricating oil L stored in the second storage space 96B. As a result, the lubricating oil L stored in the second storage space 96B flows easily from the first inlet 81A into the first helical passage 81. Consequently, the flow rate of the lubricating oil L circulating in the first helical passage 81 can be increased. As a result, the electric motor 32 can be reliably cooled by the lubricating oil L circulating in the first helical passage 81.

[0078] The second storage space 96B is defined by a bottom surface (46A) that slopes downward toward the radially inward direction. The lubricating oil L stored in the second storage space 96B is more likely to collect at the first inlet 81A located radially inward of the second storage space 96B due to the sloping bottom surface (46A). As a result, the lubricating oil L stored in the second storage space 96B flows easily from the first inlet 81A into the first helical passage 81. Consequently, the flow rate of the lubricating oil L circulating in the first helical passage 81 can be increased. As a result, the electric motor 32 can be reliably cooled by the lubricating oil L circulating in the first helical passage 81.

[0079] The first helical passage 81 extends in a left-handed spiral (either right-handed or left-handed) around the rotation axis of the rotating shaft 31. The second helical passage 90 extends in a right-handed spiral (either right-handed or left-handed) around the rotation axis of the rotating shaft 31. This allows the first helical passage 81 to be formed in such a way that the lubricating oil L flowing in from the first inlet 81A is reliably delivered to the first outlet 81B, and the second helical passage 90 to be formed in such a way that the lubricating oil L flowing in from the second inlet 90A is reliably delivered to the second outlet 90B.

[0080] Since the transmission mechanism 33 is a planetary gear mechanism, the axial length X of the transmission mechanism 33 can be shortened. This makes the electric drive device 10 more compact.

[0081] The embodiments are not limited to the above configuration and can be broadly modified. For example, the first helical passage 81 may extend in a right-handed spiral (either right-handed or left-handed) around the rotation axis of the rotation shaft 31, and the second helical passage 90 may extend in a left-handed spiral (the other of right-handed or left-handed) around the rotation axis of the rotation shaft 31.

[0082] The above embodiments may also be described as follows:

[0083] One embodiment is an electric drive device 10 comprising an electric motor 32 having a rotating shaft 31 and a drive unit 61 for driving the rotating shaft 31, a drive shaft 17, and a transmission mechanism 33 connected to the upper end (one end) of the rotating shaft 31 and the drive shaft 17, which transmits the output torque of the electric motor 32 from the rotating shaft 31 to the drive shaft 17. The electric drive device 10 comprises a case 15 and a lubricating oil passage 96 provided in the case 15 through which lubricating oil L circulates. The rotating shaft 31 is formed in a hollow cylindrical shape extending in the axial direction X of the rotating shaft 31 and has a first shaft portion 71 coupled to the drive unit 61 at the lower end (other end) of the rotating shaft 31, which is lower than the transmission mechanism 33, and a second shaft portion 72 inserted inside the first shaft portion 71, arranged coaxially with the first shaft portion 71, and having a connecting portion 87 connected to the transmission mechanism 33 at its upper end (one end), which rotates together with the first shaft portion 71. The lubricating oil passage 96 is formed in the first shaft portion 71 and has a first helical passage 81 extending spirally around the rotation axis of the rotating shaft 31, and the second shaft portion 72 The first helical passage 81 includes a second helical passage 90 formed on the first shaft portion 71 and extending spirally around the rotation axis of the rotating shaft 31, the first helical passage 81 having a first inlet 81A formed between the transmission mechanism 33 and the drive unit 61 on the first shaft portion 71 and a first outlet 81B formed on the lower end (other end) side, and is formed to send lubricating oil L that flows into the first inlet 81A due to the rotation of the first shaft portion 71 to the first outlet 81B, and the second helical passage 90 has a second inlet 90A formed on the lower end (other end) side of the rotating shaft 31 and a second outlet 90B formed on the connection portion 87, and is formed to send lubricating oil L that flows into the second inlet 90A due to the rotation of the second shaft portion 72 to the second outlet 90B.

[0084] In this embodiment, the second outlet 90B of the second helical passage 90 is provided at the connection part 87 connected to the transmission mechanism 33. Therefore, the transmission mechanism 33 can be lubricated and cooled by the lubricating oil L flowing out from the second outlet 90B. Furthermore, since the first helical passage 81 is formed in the first shaft part 71 coupled to the drive part 61 of the electric motor 32, the heat transferred from the drive part 61 of the electric motor 32 to the first shaft part 71 is cooled by the lubricating oil L flowing through the first helical passage 81. Consequently, the lubricating oil L flowing through the first helical passage 81 can cool the drive part 61 of the electric motor 32. Moreover, since the first helical passage 81 and the second helical passage 90 are formed in the rotating shaft 31, the lubricating oil passage 96 can be made smaller. As a result, the electric drive device 10 can lubricate the transmission mechanism 33 and cool the electric motor 32 with the miniaturized lubricating oil passage 96. Therefore, the electric drive device 10 includes an electric motor 32 and a transmission mechanism 33, and can achieve both cooling and miniaturization of the electric motor 32 and the transmission mechanism 33.

[0085] In one embodiment, the lubricating oil passage 96 is connected to the first outlet 81B of the first helical passage 81 and the second inlet 90A of the second helical passage 90, and has a first storage space 96A in which lubricating oil L is stored, and the second inlet 90A is immersed in the lubricating oil L stored in the first storage space 96A.

[0086] In this embodiment, the lubricating oil L that flows out from the first outlet 81B is stored in the first storage space 96A. Since the second inlet 90A is immersed in the lubricating oil L stored in the first storage space 96A, the lubricating oil L easily flows into the second inlet 90A. This increases the flow rate of the lubricating oil L circulating through the second helical passage 90. As a result, the flow rate of the lubricating oil L that flows out from the second outlet 90B and lubricates the transmission mechanism 33 increases, so that the transmission mechanism 33 can be reliably lubricated with the lubricating oil L.

[0087] In one embodiment, the first outlet 81B is positioned above the oil level OL1 of the lubricating oil L stored in the first storage space 96A.

[0088] In this embodiment, the first outlet 81B is positioned above the oil level OL1 of the lubricating oil L stored in the first storage space 96A and is not immersed in the lubricating oil L. As a result, the lubricating oil L flows out more easily from the first outlet 81B of the first helical passage 81 compared to the case where the first outlet 81B is immersed in the lubricating oil L stored in the first storage space 96A. Consequently, the flow rate of the lubricating oil L flowing through the first helical passage 81 can be increased. As a result, the electric motor 32 can be reliably cooled by the lubricating oil L flowing through the first helical passage 81.

[0089] In one embodiment, the first storage space 96A is provided at the bottom of the case 15, and a second cooling passage 58 (cooling passage) through which the refrigerant flows is provided at the bottom of the case 15.

[0090] In this embodiment, the lubricating oil L stored in the first storage space 96A is cooled by the refrigerant flowing through the second cooling passage 58 (cooling passage). The lubricating oil L then cools the electric motor 32 and the transmission mechanism 33. Therefore, the electric motor 32 and the transmission mechanism 33 can be cooled more reliably by the lubricating oil L.

[0091] In one embodiment, the first storage space 96A is provided at the bottom of the case 15, and the case 15 extends upward from the bottom and includes a plurality of spiral vertical wall portions 57 that extend spirally around the rotation axis from the outer circumference of the second shaft portion 72 radially outward from the rotation axis.

[0092] In this embodiment, a helical vertical wall portion 57 is provided around the second inlet 90A. The helical vertical wall portion 57 suppresses the radial outward flow of lubricating oil L from the second inlet 90A. This makes it easier for lubricating oil L to flow into the second inlet 90A. Consequently, the flow rate of lubricating oil L circulating through the second helical passage 90 can be increased. As a result, the transmission mechanism 33 can be reliably lubricated and cooled by the lubricating oil L.

[0093] In one embodiment, the electric motor 32 is located below the transmission mechanism 33, and the lubricating oil passage 96 is connected to the first inlet 81A of the first helical passage 81 and has a second storage space 96B in which lubricating oil L is stored, and the first inlet 81A is immersed in the lubricating oil L stored in the second storage space 96B.

[0094] In this embodiment, the first inlet 81A is immersed in the lubricating oil L stored in the second storage space 96B. As a result, the lubricating oil L stored in the second storage space 96B flows easily from the first inlet 81A into the first helical passage 81. Consequently, the flow rate of the lubricating oil L circulating in the first helical passage 81 can be increased. As a result, the electric motor 32 can be reliably cooled by the lubricating oil L circulating in the first helical passage 81.

[0095] In one embodiment, the second storage space 96B is defined by a bottom surface (46A) that slopes downward toward the radially inward direction.

[0096] According to this embodiment, the lubricating oil L stored in the second storage space 96B is more likely to collect at the first inlet 81A located radially inward of the second storage space 96B due to the inclined bottom surface (46A). As a result, the lubricating oil L stored in the second storage space 96B flows easily from the first inlet 81A into the first helical passage 81. Consequently, the flow rate of the lubricating oil L circulating in the first helical passage 81 can be increased. As a result, the electric motor 32 can be reliably cooled by the lubricating oil L circulating in the first helical passage 81.

[0097] In one embodiment, the first helical passage 81 extends in a left-handed spiral (either right-handed or left-handed), and the second helical passage 90 extends in a right-handed spiral (either right-handed or left-handed).

[0098] According to this embodiment, a first helical passage 81 can be formed to reliably deliver the lubricating oil L flowing in from the first inlet 81A to the first outlet 81B, and a second helical passage 90 can be formed to reliably deliver the lubricating oil L flowing in from the second inlet 90A to the second outlet 90B.

[0099] In one embodiment, the transmission mechanism 33 is a planetary gear mechanism having a sun gear 91 provided on the connection portion 87 of the second shaft portion 72, a plurality of planetary gears 92 that mesh with the sun gear 91, a planetary carrier 93 that rotatably supports the plurality of planetary gears 92, and a ring gear 94 that meshes with the plurality of planetary gears 92.

[0100] According to this embodiment, since the transmission mechanism 33 is a planetary gear mechanism, the axial length X of the transmission mechanism 33 can be shortened. This makes the electric drive device 10 more compact. [Explanation of symbols]

[0101] 10: Electric drive device 15: Case 17: Drive shaft 31: Rotation axis 32: Electric motor 33: Transmission mechanism 46A:Top surface (bottom surface) 57: Spiral wall section 58:Second cooling passage (cooling passage) 61: Drive unit 71: First shaft section 72: Second shaft section 81:1st spiral passage 81A: 1st inlet 81B: 1st outlet 87: Connection part 90:Second spiral passage 90A: 2nd inlet 90B: 2nd outlet 91: Sangiya 92: Planetary Gear 93: Planetary Carrier 94: Ring gear 96: Lubricating oil passage 96A: First storage space 96B: Second storage space L: Lubricating oil OL1: Oil surface X: Axial direction

Claims

1. An electric drive device comprising: an electric motor having a rotating shaft and a drive unit for driving the rotating shaft; a drive shaft; and a transmission mechanism connected to one end of the rotating shaft and the drive shaft, which transmits the output torque of the electric motor from the rotating shaft to the drive shaft, The case and, The case is provided with a lubricating oil passage through which lubricating oil flows, The aforementioned rotating shaft is A first shaft portion is formed in a hollow cylindrical shape extending in the axial direction of the rotating shaft and is coupled to the drive unit at the other end of the rotating shaft, rather than the transmission mechanism. The first shaft portion is inserted inside the first shaft portion, is arranged coaxially with the first shaft portion, has a connecting portion connected to the transmission mechanism at one end, and has a second shaft portion that rotates together with the first shaft portion. The aforementioned lubricating oil passage is A first helical passage is formed in the first shaft portion and extends spirally around the rotation axis of the rotating shaft, The second shaft portion includes a second helical passage formed therein, which extends spirally around the rotation axis of the rotation shaft, The first helical passage has a first inlet formed between the transmission mechanism and the drive unit in the first shaft portion, and a first outlet formed on the other end side, and is configured to send the lubricating oil that flows into the first inlet due to the rotation of the first shaft portion to the first outlet. The electric drive device is configured such that the second helical passage has a second inlet formed on the other end of the rotating shaft and a second outlet formed at the connection portion, and the lubricating oil that flows into the second inlet due to the rotation of the second shaft portion is sent to the second outlet.

2. The lubricating oil passage is connected to the first outlet of the first helical passage and the second inlet of the second helical passage, and has a first storage space in which the lubricating oil is stored. The electric drive device according to claim 1, wherein the second inlet is immersed in the lubricating oil stored in the first storage space.

3. The electric drive device according to claim 2, wherein the first outlet is positioned above the oil level of the lubricating oil stored in the first storage space.

4. The first storage space is provided at the bottom of the case, The electric drive device according to claim 2, wherein a cooling passage through which a refrigerant flows is provided at the bottom of the case.

5. The first storage space is provided at the bottom of the case, The electric drive device according to claim 2, wherein the case includes a plurality of spiral vertical wall portions that extend upward from the bottom and spirally from the outer circumference of the second shaft portion radially outward from the rotation axis with respect to the rotation axis.

6. The electric motor is positioned below the transmission mechanism. The lubricating oil passage is connected to the first inlet of the first helical passage and has a second storage space in which the lubricating oil is stored. The electric drive device according to claim 1, wherein the first inlet is immersed in the lubricating oil stored in the second storage space.

7. The electric drive device according to claim 1, wherein the second storage space is defined by a bottom surface that slopes downward toward the radially inward direction.

8. The first spiral passage extends in a spiral shape, either clockwise or counterclockwise. The electric drive device according to claim 1, wherein the second helical passage extends in the other direction of the spiral, either right-handed or left-handed.

9. The aforementioned transmission mechanism is The sun gear provided at the connection portion of the second shaft, Multiple planetary gears that mesh with the aforementioned sun gear, A planetary carrier that rotatably supports multiple planetary gears, The electric drive device according to claim 1, which is a planetary gear mechanism having a ring gear that meshes with a plurality of the aforementioned planetary gears.

Images