electric propulsion

Abstract

A plurality of devices provided in an electric propulsion machine are each efficiently cooled by a water-cooling method, and the cooling of such a plurality of devices is realized with a simple structure. [Solution] The outboard motor is equipped with a motor as a power source, an inverter that controls the drive of the motor, and a water-cooled cooling device 51 that cools the motor and inverter. The cooling device 51 is equipped with a water intake 52, a discharge outlet 53, a pump 54, a motor water jacket 65 that cools the motor, and an inverter water jacket 71 that cools the inverter. The motor water jacket 65 and the inverter water jacket 71 are connected in series between the water intake 52 and the discharge outlet 53 within the outboard motor 1.

Description

[Technical Field]

[0001] The present invention relates to an electric propulsion device for propelling a vessel. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2005-162055 discloses an electric outboard motor that includes an electric motor as a power source and a water-cooled cooling device that removes or reduces heat generated by the electric motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-162055 Summary of the Invention [Problem to be solved by the invention]

[0004] As the output of the motor of an electric propulsion unit increases, not only does the amount of heat generated by the motor increase, but so does the amount of heat generated by devices other than the motor. Therefore, it is necessary to efficiently cool not only the motor but also devices other than the motor using a water-cooled cooling device. For example, an electric propulsion unit is provided with an inverter that controls the drive of the motor. The inverter has a power module that generates heat during operation. When the motor is driven at high output, the amount of heat generated by the power module increases. Therefore, as the output of the motor increases, it is necessary to efficiently cool the inverter using a water-cooled cooling device.

[0005] When a device provided in an electric propulsion is cooled by a water-cooled cooling device, the device is provided with a water jacket through which cooling water flows, and the electric propulsion is provided with a cooling water supply passage that supplies cooling water to the water jacket and a cooling water discharge passage that discharges the cooling water that has flowed through the water jacket from the water jacket.

[0006] When multiple devices, including a motor, in an electric propulsion are cooled by a water-cooled cooling system, it is conceivable to provide a water jacket for each of the multiple devices and run cooling water through each of the multiple water jackets. However, in this case, a cooling water supply passage that supplies cooling water to each of the multiple water jackets and a cooling water discharge passage that discharges cooling water from each of the multiple water jackets are required, and providing such cooling water supply passages and cooling water discharge passages in the electric propulsion may complicate the structure of the electric propulsion.

[0007] The present invention has been made in consideration of the problems described above, and an object of the present invention is to provide an electric propulsion in which each of a plurality of devices provided in the electric propulsion can be efficiently cooled by a water-cooling method, and in which the cooling of such a plurality of devices can be achieved by a simple structure. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention is an electric propulsion unit for propelling a vessel, comprising: a propeller provided on a lower part of the electric propulsion unit and generating propulsive force for the vessel; a motor provided on an upper part of the electric propulsion unit and rotating the propeller; an inverter provided above the motor and controlling the drive of the motor; and a cooling device for cooling the motor and the inverter, wherein the cooling device comprises a water intake port that takes in water around the electric propulsion unit as cooling water into the electric propulsion unit; a discharge port that discharges the cooling water taken in into the electric propulsion unit to the periphery of the electric propulsion unit; a pump that circulates cooling water from the water intake port to the discharge port within the electric propulsion unit; a motor water jacket that cools the motor with the cooling water taken in into the electric propulsion unit; and an inverter water jacket that cools the inverter with the cooling water taken in into the electric propulsion unit, wherein the motor water jacket and the inverter water jacket are connected in series between the water intake port and the discharge port within the electric propulsion unit. [Effects of the Invention]

[0009] According to the present invention, each of the multiple devices provided in the electric propulsion can be efficiently cooled using a water-cooling method, and the cooling of such multiple devices can be achieved using a simple structure. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a rear view of an outboard motor according to an embodiment of the present invention; [Figure 2] 1 is an external view showing an outboard motor according to an embodiment of the present invention as viewed from the left. FIG. [Figure 3] 2 is a cross-sectional view of the outboard motor taken along line AA in FIG. 1 as viewed from the left. [Figure 4] FIG. 4 is an exploded view of the outboard motor in FIG. 3. [Figure 5] 1 is a block diagram showing the configuration of a cooling device provided in an outboard motor according to an embodiment of the present invention; [Figure 6] (A) is an enlarged cross-sectional view showing the portion of the outboard motor in Figure 3 where the water intake, pump, and reducer water jacket are arranged, (B) is an enlarged cross-sectional view showing the portion from the pump to the reducer water jacket in the outboard motor in Figure 6(A), and (C) is an enlarged cross-sectional view showing the portion from the reducer water jacket to the motor water jacket in the outboard motor in Figure 6(A). [Figure 7] 7(A) is an explanatory diagram showing a motor water jacket in an outboard motor according to an embodiment of the present invention, (B) is a cross-sectional view showing the motor cut along the cutting line DD in FIG. 7(A) as viewed from above, and (C) is a cross-sectional view showing the motor cut along the cutting line EE in FIG. 7(A) as viewed from above. [Figure 8] 8(A) is a cross-sectional view showing the outboard motor cut along the cutting line BB in FIG. 1 as viewed from the left, and FIG. 8(B) is an enlarged cross-sectional view showing the portion from the motor water jacket to the inverter water jacket in the outboard motor in FIG. 8(A). [Figure 9] 2 is a cross-sectional view of the outboard motor taken along line CC in FIG. 1 as viewed from the right. [Figure 10] FIG. 10 is a block diagram showing the configuration of a cooling device in an outboard motor according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] An electric propulsion unit according to an embodiment of the present invention is an electric propulsion unit for propelling a vessel, and includes a propeller provided at the bottom of the electric propulsion unit to generate thrust for the vessel, a motor provided at the top of the electric propulsion unit to rotate the propeller, an inverter provided above the motor to control the drive of the motor, and a cooling device to cool the motor and inverter.

[0012] In addition, in the electric propulsion of this embodiment, the cooling device includes a water intake port that takes in water around the electric propulsion into the electric propulsion as cooling water, a drain port that discharges the cooling water taken into the electric propulsion around the electric propulsion, a pump that circulates the cooling water from the water intake port to the drain port within the electric propulsion, a motor water jacket that cools the motor with the cooling water taken into the electric propulsion, and an inverter water jacket that cools the inverter with the cooling water taken into the electric propulsion.

[0013] In the electric propulsion device of this embodiment, the motor water jacket and the inverter water jacket are connected in series between the water intake and the water discharge port.

[0014] When the motor water jacket and the inverter water jacket are connected in series between the water intake and the drain, in that order, from the water intake to the drain, cooling water taken into the electric propulsion device through the water intake is supplied to the motor water jacket by the drive of the pump and flows through the motor water jacket, thereby cooling the motor. The cooling water that has flowed through the motor water jacket is then discharged from the motor water jacket, and is then supplied to the inverter water jacket and flows through the inverter water jacket, thereby cooling the inverter. The cooling water that has flowed through the inverter water jacket is then discharged from the inverter water jacket, and is then discharged from the drain to the surroundings of the electric propulsion device.

[0015] Furthermore, when the motor water jacket and inverter water jacket are connected in series between the water intake and the drain, in that order, from the water intake to the drain, cooling water taken into the electric propulsion device through the water intake is supplied to the inverter water jacket by the drive of the pump and flows through the inverter water jacket, thereby cooling the inverter. The cooling water that has flowed through the inverter water jacket is then discharged from the inverter water jacket, and is then supplied to the motor water jacket and flows through the motor water jacket, thereby cooling the motor. The cooling water that has flowed through the motor water jacket is then discharged from the motor water jacket, and is then discharged from the drain to the surroundings of the electric propulsion device.

[0016] According to the electric propulsion device of this embodiment, the motor and inverter provided in the electric propulsion device can be efficiently cooled using a water-cooling method. Furthermore, according to the electric propulsion device of this embodiment, the motor water jacket and the inverter water jacket are connected in series between the water intake and the water discharge port within the electric propulsion device, thereby enabling the water-cooling of the motor and the inverter to be achieved with a simple structure. That is, when the motor and the inverter are cooled using a water-cooling method, it is also possible to connect the motor water jacket and the inverter water jacket in parallel between the water intake and the water discharge port. However, this requires branch passages for distributing and supplying the cooling water taken into the electric propulsion device through the water intake port to the motor water jacket and the inverter water jacket, and merging passages for carrying the cooling water discharged from the motor water jacket and the inverter water jacket to the water discharge port. Providing such branch passages and merging passages in the electric propulsion device may complicate the structure of the electric propulsion device. In contrast, in the electric propulsion device of this embodiment, the motor water jacket and inverter water jacket are connected in series between the water intake and discharge ports, so no branch passages or merging passages are required, and therefore the structure for cooling the motor and inverter using a water-cooling method can be simplified. [Example]

[0017] Hereinafter, an embodiment of the electric propulsion device of the present invention will be described with reference to the drawings. In the description, when referring to the directions up (Ud), down (Dd), front (Fd), rear (Bd), left (Ld), and right (Rd), the arrows drawn at the bottom right of Figures 1 to 4, 6(A), 7(A), 7(B), 8(A), and 9 will be used.

[0018] (Outboard motor) Fig. 1 shows an outboard motor 1, which is an embodiment of an electric propulsion device of the present invention, as seen from the rear. Fig. 2 shows the outboard motor 1 as seen from the left. Fig. 3 shows a cross section of the outboard motor 1 taken along section line AA in Fig. 1, as seen from the left. Fig. 4 shows the motor 2, inverter 11, inverter mounting member 17, reducer 18, and lower unit 23, each separated, in the outboard motor 1 in Fig. 3.

[0019] The outboard motor 1 is an electric outboard motor whose power source is a motor (electric motor) 2, and generates propulsive force for the boat using the power of the motor 2. As shown in FIG. 2, the outboard motor 1 includes the motor 2, an inverter 11, a reducer 18, and a lower unit 23.

[0020] The motor 2 is mounted on top of the outboard motor 1. When the outboard motor 1 is mounted on a boat, the motor 2 is located above the water surface. The motor 2 is, for example, a permanent magnet AC synchronous motor. As shown in FIG. 3, the motor 2 has an output shaft 3, a rotor 4, a stator 5, and a motor case 6. The motor 2 is mounted on the outboard motor 1 so that the extension direction of the output shaft 3 is vertical. The rotor 4 is mounted on the outer periphery of the output shaft 3, and the stator 5 is mounted on the outer periphery of the rotor 4. As shown in FIG. 4, the motor case 6 has a case body 7, a lower bracket 8, and an upper bracket 9. The case body 7 is cylindrical. The case body 7 houses the vertical middle portion of the output shaft 3, the rotor 4, and the stator 5. The upper bracket 9 is mounted above the case body 7 and closes the case body 7 from above. The lower bracket 8 is mounted below the case body 7 and closes the case body 7 from below. An insertion hole is provided in the center of the lower bracket 8. The lower end portion of the output shaft 3 passes through the insertion hole and protrudes downward, and as shown in FIG. 3, enters the reducer 18 from above the reducer 18.

[0021] The inverter 11 is a device that controls the drive of the motor 2. The inverter 11 is provided above the motor 2. The inverter 11 is fixed to the top of the upper bracket 9 of the motor case 6 via an inverter mounting member 17. The inverter 11 has an inverter main body 12, an inverter case 13, and a cable connection part 16. The inverter main body 12 is provided with a circuit that controls the drive of the motor 2, and this circuit includes a power module. Although not shown, a cable is provided between the inverter main body 12 and the motor 2 to electrically connect them. The inverter main body 12 is also housed within the inverter case 13. The cable connection part 16 is connected to a cable for supplying power from a battery (not shown) to the inverter main body 12, a cable for transmitting control signals from a higher-level control module (not shown) to the inverter main body 12, and the like.

[0022] The reducer 18 is a device that transmits the rotation output from the motor 2 to the propeller 25 while reducing the speed. The reducer 18 is provided below the motor 2 on the upper part of the outboard motor 1. As shown in FIG. 4, the reducer 18 has a drive gear 19, a driven gear 20, and a reducer case 21. As shown in FIG. 3, the drive gear 19 and the driven gear 20 are housed between the lower bracket 8 of the motor case 6 and the reducer case 21. The drive gear 19 and the driven gear 20 are aligned in the fore-and-aft direction, with the driven gear 20 located in front of the drive gear 19. The drive gear 19 is fixed to the lower end portion of the output shaft 3 of the motor 2. The driven gear 20 is fixed to the upper end portion of the transmission shaft 26. The drive gear 19 and the driven gear 20 mesh with each other. The rotation of the output shaft 3 is transmitted to the transmission shaft 26 via the drive gear 19 and the driven gear 20. Furthermore, the number of teeth of the driven gear 20 is greater than the number of teeth of the drive gear 19, and the rotation of the output shaft 3 is reduced in speed before being transmitted to the transmission shaft 26. Note that the drive gear 19 is a specific example of a "first gear," and the driven gear 20 is a specific example of a "second gear."

[0023] The lower unit 23 is provided at the bottom of the outboard motor 1 and is arranged below the reduction gear 18. The lower unit 23 has a propeller shaft 24, a propeller 25, a transmission shaft 26, a gear mechanism 27, and a lower case 31. The propeller shaft 24 is provided at the bottom of the lower unit 23 and extends in the fore-and-aft direction. The propeller 25 is fixed to the rear end portion of the propeller shaft 24. When the outboard motor 1 is mounted on a boat, the propeller 25 is located below the water surface. The transmission shaft 26 extends downward from the reduction gear 18, passes through the front portion of the lower unit 23, and reaches the bottom portion of the lower unit 23. The gear mechanism 27 is provided at the front portion of the bottom portion of the lower unit 23. The gear mechanism 27 has a transmission gear 28, a forward gear 29, and a reverse gear 30. The transmission gear 28, the forward gear 29, and the reverse gear 30 are each a bevel gear. The transmission gear 28 is fixed to the lower end portion of the transmission shaft 26. The forward gear 29 is disposed in front of the transmission gear 28 and meshes with it. The reverse gear 30 is disposed behind the transmission gear 28 and meshes with it. The front portion of the propeller shaft 24, the lower portion of the transmission shaft 26, and the gear mechanism 27 are housed in a lower case 31.

[0024] The outboard motor 1 also includes a shift mechanism 33. The shift mechanism 33 changes the direction of thrust generated by the propeller 25 by changing the direction of rotation of the propeller 25. As shown in Fig. 3, the shift mechanism 33 includes a shift actuator 34 disposed in front of the inverter 11, an upper shift rod 35 connected to the shift actuator 34 and extending downward from it, a lower shift rod 36 connected to the lower end of the upper shift rod 35, extending downward from the lower end of the upper shift rod 35 and entering the lower case 31, a shift plunger 37 disposed in the front lower part of the lower case 31 and connected to the lower end of the lower shift rod 36, and a dog clutch 38 disposed in the lower case 31 between the forward gear 29 and the reverse gear 30 and connected to the shift plunger 37.

[0025] Driven by the motor 2, the output shaft 3 rotates. The rotation of the output shaft 3 is transmitted to the transmission shaft 26 via the reducer 18, causing the transmission shaft 26 to rotate. The rotation of the transmission shaft 26 causes the transmission gear 28 to rotate, thereby causing the forward gear 29 and the reverse gear 30 to rotate. The forward gear 29 and the reverse gear 30 rotate in opposite directions. The propeller shaft 24 extends through through holes provided in the centers of the reverse gear 30 and the forward gear 29, but does not contact either the reverse gear 30 or the forward gear 29. The dog clutch 38 rotates integrally with the propeller shaft 24, but is attached to the propeller shaft 24 so as to be movable forward and backward relative to the propeller shaft 24. Driving the shift actuator 34 rotates the upper shift rod 35 and the lower shift rod 36, and the rotation of the lower shift rod 36 is transmitted to the dog clutch 38 via the shift plunger 37, causing the dog clutch 38 to move in the fore-and-aft direction. When the dog clutch 38 moves forward, teeth on the front surface of the dog clutch 38 mesh with teeth on the inner periphery of the rear surface of the forward gear 29. This transmits the rotation of the forward gear 29 to the propeller shaft 24 via the dog clutch 38, causing the propeller shaft 24 and the propeller 25 to rotate in one direction, and the propeller 25 generates thrust that moves the boat forward. On the other hand, when the dog clutch 38 moves rearward, teeth on the rear surface of the dog clutch 38 mesh with teeth on the inner periphery of the front surface of the reverse gear 30. As a result, the rotation of the reverse gear 30 is transmitted to the propeller shaft 24 via the dog clutch 38, causing the propeller shaft 24 and the propeller 25 to rotate in the other direction, and the propeller 25 generates a thrust that moves the boat backward.

[0026] The outboard motor 1 also includes a clamp bracket 40 for attaching the outboard motor 1 to the transom of the boat, and a swivel bracket 42 for rotating the outboard motor 1 horizontally relative to the boat around a pilot shaft 41, thereby changing the direction of the propeller 25.

[0027] (cooling device) Fig. 5 shows the overall configuration of the cooling device 51. The cooling device 51 is a water-cooled type cooling device that cools multiple devices provided on the outboard motor 1, specifically the reduction gear 18, the motor 2, and the inverter 11. As shown in Fig. 5, the cooling device 51 includes a water intake 52 that takes in water around the outboard motor 1 as cooling water into the outboard motor 1, a discharge outlet 53 that discharges the cooling water taken into the outboard motor 1 around the outboard motor 1, and a pump 54 that circulates the cooling water from the water intake 52 to the discharge outlet 53 within the outboard motor 1. The cooling device 51 also includes a reduction gear water jacket 60 that cools the reduction gear 18 with the cooling water taken into the outboard motor 1, a motor water jacket 65 that cools the motor 2 with the cooling water taken into the outboard motor 1, and an inverter water jacket 71 that cools the inverter 11 with the cooling water taken into the outboard motor 1. Furthermore, the cooling device 51 is provided with a cooling water temperature control valve 83 that controls the temperature of the cooling water circulating inside the outboard motor 1.

[0028] The reducer water jacket 60, motor water jacket 65, and inverter water jacket 71 are connected in series between the water intake 52 and the discharge port 53 inside the outboard motor 1, in the order of reducer water jacket 60, motor water jacket 65, and inverter water jacket 71, from the water intake 52 toward the discharge port 53. The pump 54 is connected before the series arrangement of these three water jackets 60, 65, and 71, specifically between the water intake 52 and the reducer water jacket 60. The cooling water temperature control valve 83 is connected after the series arrangement of the three water jackets 60, 65, and 71, specifically between the inverter water jacket 71 and the discharge port 53.

[0029] The cooling water taken into the outboard motor 1 through the water intake 52 is supplied to the reducer water jacket 60 by the drive of the pump 54 and flows through the reducer water jacket 60, thereby cooling the reducer 18. The cooling water that has flowed through the reducer water jacket 60 is then discharged from the reducer water jacket 60, and is then supplied to the motor water jacket 65 and flows through the motor water jacket 65, thereby cooling the motor 2. The cooling water that has flowed through the motor water jacket 65 is then discharged from the motor water jacket 65, and is then supplied to the inverter water jacket 71 and flows through the inverter water jacket 71, thereby cooling the inverter 11. The cooling water that has flowed through the inverter water jacket 71 is then discharged from the inverter water jacket 71 and is then discharged from the drain port 53 around the outboard motor 1.

[0030] The configuration of each part of the cooling device 51 will be described in detail below using Figures 6 to 9. Figure 6(A) shows an enlarged view of the outboard motor 1 in Figure 3, including the water intake 52, pump 54, and reducer water jacket 60. Figure 6(B) shows an enlarged view of the outboard motor 1 in Figure 6(A), including the portion from the pump 54 to the reducer water jacket 60. Figure 6(C) shows an enlarged view of the outboard motor 1 in Figure 6(A), including the portion from the reducer water jacket 60 to the motor water jacket 65. Figure 7(A) schematically illustrates the configuration of the motor water jacket 65. Figure 7(B) shows a top view of the cross section of the motor 2 taken along section line DD in Figure 7(A). Figure 7(C) shows a top view of the cross section of the motor 2 taken along section line EE in Figure 7(A). Figure 8(A) shows a left-side view of the cross section of the outboard motor 1 taken along section line BB in Figure 1. Figure 8(B) shows an enlarged view of the portion of the outboard motor 1 in Figure 8(A) from the motor water jacket 65 to the inverter water jacket 71. Figure 9 shows a cross section of the outboard motor 1 taken along cutting line CC in Figure 1 as viewed from the right.

[0031] (intake, pump) As shown in Figures 2 and 6(A), the water intakes 52 are provided at the front left portion of the lower case 31 and at the front right portion of the lower case 31. Each water intake 52 is a hole that opens into the outer surface of the lower case 31. When the outboard motor 1 is mounted on a boat, each water intake 52 is located below the water surface. Each water intake 52 is also provided with a strainer to prevent underwater dust and other particles from being drawn into the outboard motor 1.

[0032] As shown in FIG. 6(A), the pump 54 is disposed below the front portion of the reducer 18. The pump 54 is, for example, a rotary variable volume water pump. The pump 54 has an impeller 55 and a pump case 56. The impeller 55 is fixed to the transmission shaft 26 and rotates integrally with the transmission shaft 26. The impeller 55 is housed in the pump case 56. The pump case 56 is attached to the upper part of the lower unit 23.

[0033] Although not shown in detail, a suction port is provided at the bottom of the pump case 56. A water intake passage 58 is also provided in the lower unit 23. Each water intake 52 and the suction port are connected to each other via the water intake passage 58. Water taken in through each water intake 52 flows into the pump case 56 as cooling water through the water intake passage 58 and the suction port. Also, as shown in FIG. 6(B), a discharge port 57 is provided at the top of the pump case 56. For example, the discharge port 57 opens at the top surface of the rear part of the pump case 56. The cooling water in the pump case 56 flows out of the pump case 56 through the discharge port 57.

[0034] (Reducer water jacket) As shown in Figure 6(A), the reducer water jacket 60 is provided in the reducer case 21. Specifically, the reducer water jacket 60 is composed of a cooling water passage 61 formed in the reducer case 21. The reducer water jacket 60 is provided in the reducer case 21 in a portion extending from below the drive gear 19 to below the driven gear 20, and extends in the front-to-rear direction from below the drive gear 19 to below the driven gear 20.

[0035] As shown in FIG. 6B , an inlet port 62 is provided at one end of the reducer water jacket 60 (one end of the cooling water passage 61), connecting the inside of the reducer water jacket 60 with the outside of the reducer water jacket 60 and allowing the cooling water to flow from the outside of the reducer water jacket 60 into the reducer water jacket 60. The inlet port 62 is located at the front end of the reducer water jacket 60. The inlet port 62 is also located opposite the discharge port 57 of the pump 54 in the vertical direction. Specifically, the inlet port 62 is located at the lower end of the inlet pipe 22, which protrudes downward from a portion of the underside of the reducer case 21 opposite the discharge port 57. The lower end of the inlet pipe 22 is inserted into the discharge port 57 of the pump 54. This directly connects the inlet port 62 and the discharge port 57. The cooling water flowing out of the discharge port 57 flows into the reducer water jacket 60 through the inlet port 62 and the inlet pipe 22.

[0036] As shown in FIG. 6(C), an outlet port 63 is provided at the other end of the reducer water jacket 60 (the other end of the cooling water passage 61), which connects the inside of the reducer water jacket 60 with the outside of the reducer water jacket 60 and allows the cooling water to flow from inside the reducer water jacket 60 to outside the reducer water jacket 60. The outlet port 63 is located in the center in the left-right direction at the top of the rear part of the reducer 18. The outlet port 63 is also located behind the drive gear 19. The outlet port 63 is also provided on the upper surface 21A of the reducer case 21. The outlet port 63 is also located at the rear end side of the reducer water jacket 60. The cooling water in the reducer water jacket 60 flows out of the reducer water jacket 60 through the outlet port 63.

[0037] (Motor water jacket) The motor water jacket 65 is provided in the motor case 6. Specifically, as shown in Figures 7(A) to 7(C), the motor water jacket 65 is composed of a cooling water passage 66 formed in the motor case 6. A part of the cooling water passage 66 is formed in the lower bracket 8, another part of the cooling water passage 66 is formed in the case body 7, and yet another part of the cooling water passage 66 is formed in the upper bracket 9. The cooling water passage 66 is provided so as to surround the stator 5 of the motor 2 from its outer periphery all around.

[0038] An inlet port 67 is provided at one end of the motor water jacket 65 (one end of the cooling water passage 66), which connects the inside of the motor water jacket 65 with the outside of the motor water jacket 65 and allows cooling water to flow from the outside of the motor water jacket 65 into the motor water jacket 65. As can be seen from FIGS. 7(A) and 7(C), the inlet port 67 is located in the center in the left-right direction below the rear of the motor 2. As shown in FIG. 6(C), the inlet port 67 is also provided on the underside 8A of the lower bracket 8. The inlet port 67 is located in a position opposite the outlet port 63 of the reducer water jacket 60 in the up-down direction. In the outboard motor 1, the reducer 18 and the motor 2 are adjacent to each other in the up-down direction, and the upper surface 21A of the reducer case 21 and the underside 8A of the lower bracket 8 face each other. The portion of the upper surface 21A of the reducer case 21 where the outlet port 63 is provided and the portion of the lower surface 8A of the lower bracket 8 where the inlet port 67 is provided are in contact with each other, thereby connecting the outlet port 63 and the inlet port 67 to each other. The cooling water that flows out of the outlet port 63 of the reducer water jacket 60 flows into the motor water jacket 65 through the inlet port 67 of the motor water jacket 65. The cooling water also flows inside the motor water jacket 65 as shown by arrow K in Figure 7(A).

[0039] Furthermore, an outlet port 68 is provided at the other end of the motor water jacket 65 (the other end of the cooling water passage 66), which connects the inside of the motor water jacket 65 with the outside of the motor water jacket 65 and allows the cooling water to flow from inside the motor water jacket 65 to outside the motor water jacket 65. As can be seen from FIGS. 7(A) and 7(B), the outlet port 68 is located on the left side of the upper rear part of the motor 2. Furthermore, as shown in FIG. 8(B), the outlet port 68 is provided on the upper surface 9A of the upper bracket 9. The cooling water in the motor water jacket 65 flows out of the motor water jacket 65 through the outlet port 68.

[0040] 8(B), a connecting passage 69 is provided at the rear left portion of the inverter mounting member 17, penetrating the inverter mounting member 17 in the vertical direction. The lower end of the connecting passage 69 opens at the bottom surface of the inverter mounting member 17, and the upper end of the connecting passage 69 opens at the top surface of the inverter mounting member 17. The opening at the bottom end of the connecting passage 69 is positioned vertically opposite the outflow port 68 of the motor water jacket 65. In the outboard motor 1, the motor 2 and the inverter mounting member 17 are adjacent to each other in the vertical direction, and the top surface 9A of the upper bracket 9 of the motor case 6 and the bottom surface of the inverter mounting member 17 face each other. The portion of the top surface 9A of the upper bracket 9 where the outflow port 68 is provided and the portion of the bottom surface of the inverter mounting member 17 where the opening at the lower end of the connecting passage 69 is provided are in contact with each other, thereby connecting the outflow port 68 and the connecting passage 69 to each other.

[0041] (Inverter water jacket) As shown in FIG. 8(A), the inverter water jacket 71 is provided in the inverter case 13. Specifically, the inverter water jacket 71 is configured by a coolant passage 72 formed in the inverter case 13. The inverter water jacket 71 is formed in the lower rear part of the inverter case 13. The inverter water jacket 71 also extends in the left-right direction from the left end to the right end of the inverter case 13.

[0042] As shown in FIG. 8B , an inlet port 73 is provided at one end of the inverter water jacket 71 (one end of the cooling water passage 72), which connects the inside of the inverter water jacket 71 with the outside of the inverter water jacket 71 and allows the cooling water to flow from the outside of the inverter water jacket 71 into the inverter water jacket 71. The inlet port 73 is located at the left end of the lower rear part of the inverter case 13. The inlet port 73 is also located at the left end of the inverter water jacket 71. The inlet port 73 is also located on the lower surface 13A of the inverter case 13. Specifically, the lower surface 13A of the inverter case 13 has an inlet pipe 14 that protrudes downward, and the inlet port 73 is located at the lower end of the inlet pipe 14. The inlet pipe 14 and the inlet port 73 are located opposite the outlet port 68 of the motor water jacket 65 in the up-down direction. The inlet pipe 14 and the inlet port 73 are vertically opposed to the opening at the upper end of a connecting passage 69 that extends vertically from the outlet port 68. The lower end of the inlet pipe 14 is inserted into the opening at the upper end of the connecting passage 69. This directly connects the inlet port 73 and the connecting passage 69 to each other. The cooling water that flows out of the outlet port 68 of the motor water jacket 65 flows into the inverter water jacket 71 through the connecting passage 69, the inlet port 73, and the inlet pipe 14.

[0043] In addition, the cooling water passage 72 of the inverter water jacket 71 extends in the left-right direction from the left end to the right end of the inverter case 13, and then extends upward at the right end of the inverter case 13, then extends rearward, and then extends downward, as shown in Figure 9.

[0044] An outlet port 74 is provided at the other end of the inverter water jacket 71 (the other end of the cooling water passage 72), which connects the inside of the inverter water jacket 71 with the outside of the inverter water jacket 71 and allows the cooling water to flow from inside the inverter water jacket 71 to outside the inverter water jacket 71. The outlet port 74 is located at the right end portion of the lower rear part of the inverter case 13. The outlet port 74 is also located at the right end portion of the inverter water jacket 71. The outlet port 74 is also provided on the lower surface 13A of the inverter case 13. Specifically, an outlet pipe portion 15 that protrudes downward is provided on the lower surface 13A of the inverter case 13, and the outlet port 74 is located at the lower end of the outlet pipe portion 15. The cooling water in the inverter water jacket 71 flows out of the inverter water jacket 71 through the outlet port 74.

[0045] (Configuration related to drainage) 3, the water drain port 53 is provided inside the hub of the propeller 25. The outboard motor 1 is equipped with a connecting passage 76, a connecting passage 77, a water drain pipe 78, a water drain passage 80, and a water drain passage 81 as passages for carrying the cooling water that flows out from the outlet port 68 of the inverter water jacket 71 to the water drain port 53.

[0046] As shown in Figure 9, the connecting passage 76 is provided at the rear right of the inverter mounting member 17. The connecting passage 76 extends in the vertical direction, with an upper opening of the connecting passage 76 opening to the upper surface of the inverter mounting member 17 and a lower opening of the connecting passage 76 opening to the lower surface of the inverter mounting member 17. The lower end of the outflow pipe portion 15 of the inverter water jacket 71 is inserted into the upper opening of the connecting passage 76, thereby connecting the outflow port 74 of the inverter water jacket 71 and the connecting passage 76 to each other.

[0047] 9, the connecting passage 77 is provided at the rear right of the upper bracket 9 of the motor case 6. The connecting passage 77 extends in the vertical direction, with an opening at the upper end of the connecting passage 77 opening to the upper surface of the upper bracket 9 and an opening at the lower end of the connecting passage 77 opening to the lower surface of the upper bracket 9.

[0048] Additionally, the upper opening of the connection passage 77 faces the lower opening of the connection passage 76 in the vertical direction. The portion of the inverter mounting member 17 where the lower opening of the connection passage 76 is provided and the portion of the upper bracket 9 where the upper opening of the connection passage 77 is provided are in contact with each other, thereby connecting the connection passages 76 and 77 to each other.

[0049] As shown in FIG. 9, the upper end of the drain pipe 78 is connected to the lower end of the connecting passage 77. The drain pipe 78 extends downward from the connecting passage 77, which is provided at the right rear of the upper bracket 9 of the motor case 6, and then bends downward and left as shown in FIG. 1, then extends downward and left, bends downward, and then extends downward again. The lower end of the drain pipe 78 is located in the center of the outboard motor 1 in the left-right direction. As shown in FIG. 6(A), the lower end of the drain pipe 78 is connected to the rear of the reducer case 21 via a joint 79. As can be seen from FIGS. 6(A) and 9, the drain pipe 78 passes outside the motor 2 and at a position away from the motor 2.

[0050] As shown in FIG. 6(A), a drain passage 80 is provided at the rear of the reducer case 21. A drain pipe 78 is connected to the drain passage 80 via a joint 79. A drain passage 81 is provided at the rear of the lower case 31. The drain passage 81 is connected to the drain passage 80. Although not shown in detail, the drain passage 81 is connected to the drain outlet 53 within the lower case 31.

[0051] The cooling water flowing out from the outlet port 68 of the inverter water jacket 71 passes through the connecting passage 76, the connecting passage 77, the drain pipe 78, the drain passage 80 and the drain passage 81 in that order, and is discharged from the drain outlet 53 around the outboard motor 1.

[0052] (Cooling water temperature control valve) As shown in FIG. 9 , the cooling water temperature control valve 83 is provided at the other end (terminal end) of the cooling water passage 72 of the inverter water jacket 71. The cooling water temperature control valve 83 changes its valve opening depending on the temperature of the cooling water flowing through the terminal end portion of the cooling water passage 72 that constitutes the inverter water jacket 71, thereby changing the amount of cooling water flowing out from the outlet port 74 of the inverter water jacket 71. For example, the higher the temperature of the cooling water flowing through the terminal end portion of the cooling water passage 72, the larger the valve opening of the cooling water temperature control valve 83, thereby increasing the amount of cooling water flowing out from the outlet port 74 of the inverter water jacket 71. A thermostat, for example, can be used as the cooling water temperature control valve 83.

[0053] The cooling water temperature control valve 83 can adjust the temperature of the cooling water circulating through the outboard motor 1 in accordance with the total amount of heat generated by the multiple devices in the outboard motor 1 that are to be cooled by the cooling device 51. That is, in the outboard motor 1, cooling water taken in through the water intake 52 flows through the reducer water jacket 60, then through the motor water jacket 65, then through the inverter water jacket 71, and then is discharged through the outlet 53. Therefore, the temperature of the cooling water circulating through the terminal end portion of the cooling water passage 72 of the inverter water jacket 71 is increased by the heat generated by the multiple devices in the outboard motor 1 that are to be cooled by the cooling device 51, specifically the reducer 18, the motor 2, and the inverter 11. Therefore, the total amount of heat generated by the multiple devices in the outboard motor 1 that are to be cooled by the cooling device 51 can be estimated based on the temperature of the cooling water circulating through the terminal end portion of the cooling water passage 72. Furthermore, by changing the amount of cooling water flowing out from the outlet port 74 of the inverter water jacket 71, it is possible to change the amount of cooling water circulating within the outboard motor 1, specifically, the amount of cooling water flowing through the reducer water jacket 60, the motor water jacket 65, and the inverter water jacket 71. Furthermore, by changing the amount of cooling water flowing through the outboard motor 1, it is possible to adjust the temperature of the cooling water flowing through the outboard motor 1. Specifically, by increasing the amount of cooling water flowing through the outboard motor 1, it is possible to lower the temperature of the cooling water flowing through the outboard motor 1. Therefore, by changing the amount of cooling water flowing through the terminal end portion of the cooling water passage 72 of the inverter water jacket 71, it is possible to control the temperature of the cooling water flowing through the outboard motor 1 in accordance with the total heat generation of multiple devices in the outboard motor 1 that are to be cooled by the cooling device 51.

[0054] As described above, the outboard motor 1 according to the embodiment of the present invention has the reducer water jacket 60, the motor water jacket 65, and the inverter water jacket 71, and these three water jackets 60, 65, and 71 are connected in series between the water intake 52 and the water discharge port 53. This allows the reducer 18, the motor 2, and the inverter 11 to be efficiently cooled by a water-cooling method, and also allows the reduction gear 18, the motor 2, and the inverter 11 to be cooled with a simple structure.

[0055] If three water jackets 60, 65, 71 were connected in parallel between the water intake 52 and the water discharge port 53, it would be necessary to provide branch passages for distributing and supplying the cooling water taken in through the water intake 52 to the three water jackets 60, 65, 71, and a junction passage for merging the cooling water after flowing through the three water jackets 60, 65, 71 and carrying it to the water discharge port 53. However, providing such branch passages and junction passages in the outboard motor could complicate the structure of the outboard motor. In contrast, in the outboard motor 1 of this embodiment, the three water jackets 60, 65, 71 are connected in series between the water intake 52 and the water discharge port 53, so no branch passages or junction passages are necessary. This simplifies the structure for efficiently cooling the reducer 18, motor 2, and inverter 11 using a water-cooling method.

[0056] Furthermore, in the outboard motor 1 of this embodiment, the reducer water jacket 60, the motor water jacket 65, and the inverter water jacket 71 are arranged in a straight line from bottom to top of the outboard motor 1 as a whole. This simplifies the layout of the passages for circulating cooling water through the three water jackets 60, 65, and 71. This allows the cooling water to flow smoothly through the three water jackets 60, 65, and 71 in sequence, improving the cooling efficiency of the reducer 18, the motor 2, and the inverter 11.

[0057] Furthermore, in the outboard motor 1 of this embodiment, the outlet port 68 of the motor water jacket 65 is provided on the upper surface 9A of the upper bracket 9 of the motor case 6, and the inlet port 73 of the inverter water jacket 71 is provided on the lower surface 13A of the inverter case 13, with the outlet port 68 of the motor water jacket 65 and the inlet port 73 of the inverter water jacket 71 facing each other in the up-down direction. This simplifies the connection structure between the motor water jacket 65 and the inverter water jacket 71. Furthermore, the cooling water passage connecting the motor water jacket 65 and the inverter water jacket 71 can be shortened, allowing for smoother circulation of the cooling water.

[0058] Furthermore, in the outboard motor 1 of this embodiment, the motor 2 and the inverter mounting member 17 are adjacent to each other in the vertical direction, and the inverter mounting member 17 and the inverter 11 are adjacent to each other in the vertical direction. The inverter mounting member 17 is provided with a connecting passage 69. The outflow port 68 and the connecting passage 69 are connected to each other by bringing a portion of the upper surface 9A of the upper bracket 9 of the motor case 6, where the outflow port 68 is provided, into contact with a portion of the lower surface of the inverter mounting member 17, where the lower end opening of the connecting passage 69 is provided. The connecting passage 69 and the inflow port 73 are connected to each other by inserting the lower end of the inflow pipe portion 14 of the inverter case 13 into the upper end opening of the connecting passage 69 provided in the upper surface of the inverter mounting member 17. This configuration simplifies the connection structure between the motor water jacket 65 and the inverter water jacket 71. Furthermore, the motor water jacket 65 and the inverter water jacket 71 can be easily connected during the manufacture of the outboard motor 1. Specifically, simply by attaching the inverter mounting member 17 to the motor 2 and then attaching the inverter 11 to the inverter mounting member 17, the outlet port 68 of the motor water jacket 65 and the inlet port 73 of the inverter water jacket 71 can be connected to each other via the connecting passage 69. This connection method simplifies the work of connecting the outlet port 68 and the inlet port 73 compared to, for example, a method of connecting the outlet port 68 and the inlet port 73 using a hose.

[0059] In the outboard motor 1 of this embodiment, the inverter 11 is disposed above the motor 2, and the inverter water jacket 71 is provided below the inverter case 13. This configuration allows the inverter water jacket 71 and the motor water jacket 65 to be closer to each other, shortening the cooling water passage connecting the motor water jacket 65 and the inverter water jacket 71. This allows for smoother circulation of the cooling water.

[0060] In the outboard motor 1 of this embodiment, the outlet port 63 of the reducer water jacket 60 is provided on the upper surface 21A of the reducer case 21, and the inlet port 67 of the motor water jacket 65 is provided on the lower surface 8A of the lower bracket 8 of the motor case 6, with the outlet port 63 of the reducer water jacket 60 and the inlet port 67 of the motor water jacket 65 facing each other in the vertical direction. This simplifies the connection structure between the reducer water jacket 60 and the motor water jacket 65. Furthermore, the cooling water passage connecting the reducer water jacket 60 and the motor water jacket 65 can be shortened, allowing for smoother circulation of the cooling water.

[0061] Furthermore, in the outboard motor 1 of this embodiment, the reducer 18 and the motor 2 are adjacent to each other in the vertical direction, and the outlet port 63 and the inlet port 67 are connected to each other by bringing the portion of the upper surface 21A of the reducer case 21 where the outlet port 63 is provided into contact with the portion of the lower surface 8A of the upper bracket 9 of the motor case 6 where the inlet port 67 is provided. This configuration simplifies the connection structure between the reducer water jacket 60 and the motor water jacket 65. Furthermore, during the manufacture of the outboard motor 1, the connection between the reducer water jacket 60 and the motor water jacket 65 can be easily performed. Specifically, the outlet port 63 of the reducer water jacket 60 and the inlet port 67 of the motor water jacket 65 can be connected to each other simply by attaching the motor 2 to the reducer 18. This connection method simplifies the connection between the outlet port 63 and the inlet port 67 compared to, for example, a method of connecting the outlet port 63 and the inlet port 67 using a hose.

[0062] In the reducer 18 of the outboard motor 1 of this embodiment, the reducer water jacket 60 is provided in a section extending from below the drive gear 19 to below the driven gear 20. This improves the cooling efficiency of both the drive gear 19 and the driven gear 20.

[0063] In the outboard motor 1 of this embodiment, the pump 54 is disposed below the reducer 18, and the inlet port 62 of the reducer water jacket 60 faces the discharge port 57 provided in the pump case 56 of the pump 54. This simplifies the connection structure between the pump 54 and the reducer water jacket 60. It also shortens the cooling water passage connecting the pump 54 and the reducer water jacket 60, allowing for smoother circulation of the cooling water.

[0064] Furthermore, in the outboard motor 1 of this embodiment, the discharge port 57 of the pump 54 and the inlet port 62 of the reducer water jacket 60 are connected to each other by inserting the inlet pipe portion 22 of the reducer case 21 into the discharge port 57 of the pump 54. This configuration simplifies the connection structure between the pump 54 and the reducer water jacket 60. Also, during the manufacture of the outboard motor 1, the pump 54 and the reducer water jacket 60 can be easily connected. Specifically, the pump 54 and the reducer water jacket 60 can be connected simply by attaching the reducer 18 to the lower unit 23.

[0065] The outboard motor 1 of this embodiment also includes a drain pipe 78 that carries the cooling water that has flowed out from the outlet port 74 of the inverter water jacket 71 to the drain port 53, and the drain pipe 78 is located outside the motor 2 and at a distance from the motor 2. Because the drain pipe 78 is located at a distance from the motor 2, it is possible to prevent the temperature of the motor 2 from rising due to high-temperature cooling water flowing through the drain pipe 78.

[0066] In the outboard motor 1 of this embodiment, the reducer water jacket 60, the motor water jacket 65, and the inverter water jacket 71 are arranged in this order from the water intake 52 toward the water discharge port 53. The outboard motor 1 also includes a cooling water temperature control valve 83 that changes the amount of cooling water flowing out of the inverter water jacket 71 in accordance with the temperature of the cooling water flowing through the terminal end portion of the cooling water passage 72 that constitutes the inverter water jacket 71, the final stage of the three water jackets 60, 65, 71 provided on the outboard motor 1. With an outboard motor 1 configured in this way, it is possible to achieve, with a simple configuration, control of the temperature of the cooling water flowing through the outboard motor 1 in accordance with the total heat generation of the reducer 18, the motor 2, and the inverter 11.

[0067] The outboard motor 1 of this embodiment is configured to change the rotation direction of the propeller 25 by switching, using the shift mechanism 33, whether the rotation of the motor 2 is transmitted to the propeller shaft 24 via the forward gear 29 or via the reverse gear 30. This configuration allows the rotation direction of the propeller 25 to be changed even when the rotation direction of the motor 2 is always constant, thereby changing the forward or backward direction of the thrust generated by the outboard motor 1. This allows the rotation direction of the impeller 55 of the pump 54, which is fixed to the transmission shaft 26, to be always constant, thereby extending the life of the impeller 55. Unlike an internal combustion engine, the rotation direction of the output shaft of a motor can be easily changed by controlling the drive. Therefore, the rotation direction of the propeller can be changed by controlling the drive of the motor. However, in the outboard motor 1 of this embodiment, the impeller 55 of the pump 54 is fixed to the transmission shaft 26, which transmits the rotation of the output shaft 3 of the motor 2 to the propeller 25. Therefore, if the rotation direction of the propeller 25 is changed by changing the rotation direction of the output shaft 3 of the motor 2, the rotation direction of the impeller 55 also changes when the rotation direction of the motor 2 is changed. If the impeller 55 is made of rubber, for example, the impeller 55 will undergo significant deformation when the rotation direction of the impeller 55 is switched. Repeated large deformation of the impeller 55 makes the impeller 55 more susceptible to damage and shortens the life of the impeller 55. With the outboard motor 1 of this embodiment, the rotation direction of the impeller 55 can be kept constant at all times, preventing large deformation of the impeller 55 and extending the life of the impeller 55.

[0068] In the cooling system 51 for the outboard motor 1 of the above embodiment, the reducer water jacket 60, the motor water jacket 65, and the inverter water jacket 71 are connected in series from the water intake 52 to the water discharge port 53 in the order of reducer water jacket 60, motor water jacket 65, and inverter water jacket 71. However, the present invention is not limited to this. As in a cooling system 91 shown in FIG. 10 , the reducer water jacket 60, the motor water jacket 65, and the inverter water jacket 71 may be connected in series from the water intake 52 to the water discharge port 53 in the order of inverter water jacket 71, motor water jacket 65, and reducer water jacket 60. In this case, it is preferable to connect a pump 54 between the water intake 52 and the inverter water jacket 71. It is also preferable to connect a cooling water temperature control valve 92 between the reducer water jacket 60 and the water discharge port 53.

[0069] Also, for example, as shown in FIG. 10, a temperature sensor 93 for detecting the temperature of the cooling water may be provided in each of the inverter water jacket 71, the motor water jacket 65, and the reducer water jacket 60, and the valve opening of the cooling water temperature control valve 92 may be changed based on the cooling water temperatures detected by these temperature sensors 93.

[0070] Furthermore, in the outboard motor 1 of the above embodiment, when the motor 2 is provided above the reducer 18, the lower bracket 8 of the motor case 6 is provided on the upper surface 21A of the reducer case 21, and the upper surface 21A and the lower surface 8A are in contact with each other. However, a sealing member such as a gasket may be provided between the upper surface 21A and the lower surface 8A. That is, a sealing member may be provided on the upper surface 21A of the reducer case 21, and the lower bracket 8 may be provided on the sealing member. In this case, a hole is provided in the sealing member to communicate the outlet port 63 of the reducer water jacket 60 with the inlet port 67 of the motor water jacket 65. Furthermore, in the outboard motor 1 of the above embodiment, when the inverter mounting member 17 is provided above the motor 2, the inverter mounting member 17 is provided on the upper surface 9A of the upper bracket 9 of the motor case 6, and the upper surface 9A and the lower surface of the inverter mounting member 17 are in contact with each other. However, a sealing member such as a gasket may be provided between the upper surface 9A and the lower surface of the inverter mounting member 17. That is, a seal member may be provided on the upper surface 9A of the upper bracket 9, and the inverter mounting member 17 may be provided on the seal member. In this case, a hole is provided in the seal member to allow communication between the outflow port 68 of the motor water jacket 65 and the connecting passage 69.

[0071] Furthermore, in the above embodiment, the inverter 11 is provided above the motor 2 via the inverter mounting member 17, but the inverter 11 may also be provided directly above the motor 2.

[0072] The present invention can also be applied to electric outboard motors that do not have a reduction gear water jacket, and can also be applied to other types of electric propulsion units, such as electric inboard / outboard motors.

[0073] The present invention may be modified as appropriate within the scope of the claims and the gist or concept of the invention as can be read from the entire specification, and electric propulsion devices with such modifications are also included in the technical concept of the present invention. [Explanation of symbols]

[0074] 1 Outboard motor (electric propulsion unit) 2 motors 3 Output shaft 6 Motor case 8 Lower bracket 8A Bottom 9 Upper bracket 9A Top 11 Inverter 13 Inverter case 13A Bottom 18 Reducer 19 Drive gear (first gear) 20 Driven gear (second gear) 21 Reducer case 21A Top 25 propellers 26 Transmission shaft 51, 91 Cooling device 52 Water Intake 53 Drain 54 Pump 56 Pump case 57 Discharge port 60 Reducer water jacket 62 Inlet port 63 Outlet Port 65 Motor water jacket 67 Inlet Port 68 Outlet Port 71 Inverter water jacket 73 Inlet Port 74 Outlet Port 78 Drain pipe 83, 92 Coolant temperature control valve (valve)

Claims

1. An electric propulsion device for propelling a vessel, a propeller provided below the electric propulsion unit to generate a propulsive force for the vessel; and a motor provided on an upper portion of the electric propulsion unit and configured to rotate the propeller; an inverter provided above the motor and controlling the driving of the motor; a cooling device that cools the motor and the inverter, The cooling device is a water intake that takes in water around the electric propulsion device into the electric propulsion device as cooling water; a drain port that discharges the cooling water taken into the electric propulsion device to the periphery of the electric propulsion device; a pump that circulates cooling water from the water intake to the water discharge port within the electric propulsion device; a motor water jacket that cools the motor with cooling water taken into the electric propulsion device; an inverter water jacket that cools the inverter with cooling water taken into the electric propulsion machine, an electric propulsion device, wherein the motor water jacket and the inverter water jacket are connected in series between the water intake and the water discharge port within the electric propulsion device;

2. the motor water jacket is provided in a motor case of the motor, Ports are provided at both ends of the motor water jacket to communicate between the inside of the motor water jacket and the outside of the motor water jacket, One port of the motor water jacket is provided on the top surface of the motor case, the inverter water jacket is provided in an inverter case of the inverter, Ports are provided at both ends of the inverter water jacket to communicate between the inside of the inverter water jacket and the outside of the inverter water jacket, one port of the inverter water jacket is provided on the bottom surface of the inverter case, 2. The electric propulsion device according to claim 1, wherein the one port of the motor water jacket and the one port of the inverter water jacket are at least partially opposed to each other.

3. 2. The electric propulsion device according to claim 1, wherein the inverter water jacket is provided below an inverter case of the inverter.

4. a reducer that is provided below the motor in an upper portion of the electric propulsion device and that transmits rotation output from the motor to the propeller while reducing the speed of the rotation; the cooling device includes a reducer water jacket that cools the reducer with cooling water taken into the electric propulsion machine, 2. The electric propulsion according to claim 1, wherein the reducer water jacket, the motor water jacket, and the inverter water jacket are connected in series within the electric propulsion between the water intake and the discharge outlet, from the water intake toward the discharge outlet, in the order of the reducer water jacket, the motor water jacket, and the inverter water jacket, or in the order of the inverter water jacket, the motor water jacket, and the reducer water jacket.

5. the motor water jacket is provided in a motor case of the motor, Ports are provided at both ends of the motor water jacket to communicate between the inside of the motor water jacket and the outside of the motor water jacket, One port of the motor water jacket is provided on the lower surface of the motor case, the reducer water jacket is provided in a reducer case of the reducer, Ports are provided at both ends of the reducer water jacket to communicate between the inside of the reducer water jacket and the outside of the reducer water jacket, one port of the reducer water jacket is provided on the top surface of the reducer case, 5. The electric propulsion device according to claim 4, wherein the one port of the motor water jacket and the one port of the reducer water jacket are at least partially opposed to each other.

6. a transmission shaft extending downward from the reducer and transmitting the rotation output from the reducer to the propeller; The motor has an output shaft extending in a vertical direction, a lower end portion of the output shaft entering the reducer from above the reducer, the reducer has a first gear and a second gear that rotates due to rotation of the first gear, the first gear is attached to a lower end portion of the output shaft, the second gear is attached to an upper end portion of the transmission shaft, 6. The electric propulsion device according to claim 5, wherein the reducer water jacket is provided in the reducer case in a portion extending from below the first gear to below the second gear.

7. the pump is disposed below the reducer, 7. The electric propulsion device according to claim 6, wherein the other port of the reducer water jacket is at least partially opposed to a discharge port provided in a pump case of the pump.

8. the cooling device includes a drain pipe that carries the cooling water flowing out from the other port of the inverter water jacket to the drain outlet, 3. The electric propulsion device according to claim 2, wherein the drain pipe passes outside the motor at a position spaced apart from the motor.

9. In the cooling device, cooling water taken into the electric propulsion machine through the water intake port flows through the motor water jacket, then flows through the inverter water jacket, and then is discharged from the electric propulsion machine through the drain port, 2. The electric propulsion according to claim 1, wherein the cooling device includes a valve that changes the amount of cooling water flowing out of the inverter water jacket in accordance with the temperature of the cooling water flowing through a terminal end portion of a cooling water passage that constitutes the inverter water jacket.

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