electric propulsion

Abstract

Prevents corrosion of the cooling jacket. [Solution] The electric propulsion unit 1 includes a motor 3 that rotates a propeller 16, and a cooling device that cools the motor 3. The cooling device includes a first cooling system and a second cooling system, the first cooling system includes a heat exchanger 45 that uses water outside the electric propulsion unit 1 as cooling water to cool a refrigerant, and supply passages (cooling water passages 51, 53, etc.) that supply water outside the electric propulsion unit 1 to the heat exchanger 45 as cooling water, and the second cooling system includes a motor cooling jacket 61 that is provided on the motor 3 and cools the motor 3 using the refrigerant, and circulation passages (refrigerant passages 73, 75, etc.) that circulate the refrigerant between the heat exchanger 45 and the motor cooling jacket 61.

Description

[Technical Field]

[0001] The present invention relates to an electric propulsion unit that propels a vessel. [Background technology]

[0002] Electric marine propulsion devices, i.e., electric propulsion devices, are known that include a motor (electric motor) as a power source for rotating a propeller. Some electric propulsion devices include a cooling jacket for the motor, and a cooling device that draws water from outside the electric propulsion device (e.g., seawater) into the electric propulsion device and flows that water as cooling water through the cooling jacket of the motor to cool the motor. For example, Japanese Patent Application Laid-Open Publication No. 2005-162055 describes such an electric propulsion device. [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] However, when seawater is passed through a metal cooling jacket to cool a motor, the cooling jacket corrodes due to the seawater. Compared to, for example, pipes connected to a pump that draws seawater, the flow passages in the cooling jacket are smaller in diameter and more complex, and the walls surrounding the flow passages are thinner, so corrosion can quickly damage the cooling jacket, potentially causing leakage of cooling water.

[0005] The present invention has been made in view of the problems described above, and an object of the present invention is to provide an electric propulsion device that can suppress corrosion of the cooling jacket. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides an electric propulsion device comprising a motor that rotates a propeller and a cooling device that cools the motor, wherein the cooling device comprises a first cooling system and a second cooling system, the first cooling system comprising a heat exchanger that uses water outside the electric propulsion as cooling water to cool a refrigerant, and a supply passage that supplies water outside the electric propulsion as cooling water to the heat exchanger, and the second cooling system comprising a motor cooling jacket that is provided on the motor and cools the motor using the refrigerant, and a circulation passage that circulates the refrigerant between the heat exchanger and the motor cooling jacket. [Effects of the Invention]

[0007] According to the present invention, corrosion of the cooling jacket can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an explanatory diagram showing an electric propulsion device according to a first embodiment of the present invention as viewed from the left. [Figure 2] 1 is an explanatory diagram showing an electric propulsion device according to a first embodiment of the present invention as viewed from behind. [Figure 3] 3 is a cross-sectional view of the electric propulsion taken along the line III-III in FIG. 2 as viewed from the left. [Figure 4] 1 is an exploded view of a portion of an electric propulsion device according to a first embodiment of the present invention. [Figure 5] 1 is a block diagram showing a cooling device in an electric propulsion device according to a first embodiment of the present invention. [Figure 6] 4 is an enlarged cross-sectional view of the electric propulsion machine in FIG. 3, showing a water intake, a water pump, a reduction gear cooling jacket, a heat exchanger, and the like. [Figure 7] 1 is an external view of a heat exchanger provided in an electric propulsion device according to a first embodiment of the present invention. [Figure 8] 13 is a cross-sectional view showing a motor and an inverter in the electric propulsion taken along the line XIII-XIII in FIG. 2. [Figure 9]FIG. 10(A) is an explanatory diagram showing an electric propulsion device according to a second embodiment of the present invention as seen from the left, and FIG. 10(B) is an explanatory diagram showing a lower part of the electric propulsion device as seen from behind. [Figure 10] FIG. 5 is a block diagram showing a cooling device in an electric propulsion device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] An electric propulsion according to an embodiment of the present invention includes a motor that rotates a propeller and a cooling device that cools the motor. The cooling device in the electric propulsion according to this embodiment includes a first cooling system and a second cooling system. The first cooling system includes a heat exchanger that uses water outside the electric propulsion as cooling water to cool a refrigerant, and a supply passage that supplies water outside the electric propulsion as cooling water to the heat exchanger. The second cooling system is provided on the motor and includes a motor cooling jacket that cools the motor using a refrigerant, and a circulation passage that circulates the refrigerant between the heat exchanger and the motor cooling jacket.

[0010] In the electric propulsion of this embodiment, water outside the electric propulsion (for example, seawater) is supplied as cooling water to the heat exchanger via a supply passage, where heat is exchanged between this cooling water and a refrigerant, cooling the refrigerant. After cooling the refrigerant, the cooling water is discharged outside the electric propulsion. Furthermore, the refrigerant cooled in the heat exchanger is supplied to the motor cooling jacket via a circulation passage, and the motor is cooled by this refrigerant flowing through the motor cooling jacket. After cooling the motor, the refrigerant returns to the heat exchanger.

[0011] As described above, in the electric propulsion of this embodiment, when cooling the motor, water from outside the electric propulsion does not flow through the motor cooling jacket. In other words, seawater does not flow through the motor cooling jacket. This prevents corrosion of the motor cooling jacket due to seawater. This therefore suppresses corrosion of the motor cooling jacket. [Example]

[0012] Several embodiments of the present invention will be described with reference to the drawings. In the description of each embodiment, the directions of upper (Ud), lower (Dd), front (Fd), back (Bd), left (Ld), and right (Rd) are indicated by the arrows at the bottom in Figures 1 to 4, 6, 8, and 9.

[0013] (Electric propulsion machine) Fig. 1 shows an electric propulsion unit 1 according to a first embodiment of the present invention as seen from the left. Fig. 2 shows the electric propulsion unit 1 as seen from the rear. Fig. 3 shows a cross section of the electric propulsion unit 1 taken along section line III-III in Fig. 2 as seen from the left. Fig. 4 shows the electric propulsion unit 1 in a partially disassembled state.

[0014] The electric propulsion unit 1 is an electric marine propulsion unit that propels a marine vessel. As shown in Fig. 1, the electric propulsion unit 1 of this embodiment is an outboard motor that is attached to a marine vessel. As shown in Fig. 3, the electric propulsion unit 1 includes an electric propulsion unit main body 2, which includes a motor 3, an inverter 6, a reduction gear 11, a drive shaft 14, a propeller shaft 15, a propeller 16, and a rotation transmission mechanism 17. The reduction gear 11 is a specific example of a "first transmission mechanism," and the rotation transmission mechanism 17 is a specific example of a "second transmission mechanism."

[0015] The motor 3 is a power source that rotates the propeller 16. The motor 3 is, for example, an AC motor, and includes an output shaft 4, a rotor, a stator, and a motor case 5. The output shaft 4, excluding the end that extracts rotor rotation, the rotor, and the stator, are housed in the motor case 5. The motor 3 is located on top of the electric propulsion unit body 2. When the electric propulsion unit 1 is attached to a boat, the motor 3 is located above the water surface. The motor 3 is located on the electric propulsion unit body 2 so that the extension direction of the output shaft 4 is vertical. Furthermore, as shown in FIG. 1, the motor 3 is located below the upper end of the swivel bracket 33.

[0016] The inverter 6 is a device that controls the driving of the motor 3. As shown in FIG. 3 , the inverter 6 includes an inverter main body 7 that is provided with circuits and the like that control the driving of the motor 3, and an inverter case 8 that houses the inverter main body 7. The inverter 6 is disposed above the motor 3. The inverter 6 is attached to the motor 3 via an inverter mounting member 10.

[0017] The reduction gear 11 is a device that reduces the rotation speed of the output shaft 4 of the motor 3 and transmits it to the drive shaft 14. The reduction gear 11 is disposed below the motor 3. The reduction gear 11 includes a drive gear 12 and a driven gear 13. The drive gear 12 is connected to the lower end of the output shaft 4 of the motor 3 and rotates integrally with the output shaft 4. The driven gear 13 is disposed in front of the drive gear 12, connected to the upper end of the drive shaft 14, and meshes with the drive gear 12.

[0018] The drive shaft 14 is located forward of the output shaft 4 of the motor 3 and extends in the vertical direction from the reduction gear 11 to the rotation transmission mechanism 17. As described above, the driven gear 13 is coupled to the upper end of the drive shaft 14, and the drive shaft 14 rotates integrally with the driven gear 13.

[0019] The propeller shaft 15 is disposed below the motor 3 and extends in the front-to-rear direction. The propeller 16 is attached to the rear of the propeller shaft 15 and rotates integrally with the propeller shaft 15. The propeller shaft 15 and the propeller 16 are disposed below the electric propulsion unit main body 2. When the electric propulsion unit 1 is attached to a boat, the propeller shaft 15 and the propeller 16 are located below the water surface.

[0020] The rotation transmission mechanism 17 is a mechanism that transmits the rotation of the drive shaft 14 to the propeller shaft 15. The rotation transmission mechanism 17 includes a transmission gear 18, a forward gear 19, a reverse gear 20, a dog clutch 21, and a shift plunger 22. The transmission gear 18, the forward gear 19, and the reverse gear 20 are all bevel gears. The rotation axis of the transmission gear 18 extends in the vertical direction. The transmission gear 18 is coupled to the lower end of the drive shaft 14 and rotates integrally with the drive shaft 14. The rotation axes of the forward gear 19 and the reverse gear 20 extend in the front-to-rear direction. The forward gear 19 is disposed in front of the transmission gear 18, and the reverse gear 20 is disposed behind the transmission gear 18. The forward gear 19 and the reverse gear 20 are each meshed with the transmission gear 18, and the forward gear 19 and the reverse gear 20 rotate in opposite directions upon receiving the rotation of the transmission gear 18. A through-hole is formed in the center of the forward gear 19 and the center of the reverse gear 20, and the front portion of the propeller shaft 15 is inserted into these through-holes. The forward gear 19 and the reverse gear 20 are not fixed to the propeller shaft 15 but are rotatable relative to the propeller shaft 15. A dog clutch 21 is disposed between the forward gear 19 and the reverse gear 20. The dog clutch 21 is attached to the front portion of the propeller shaft 15 so as to be unrotatable relative to the propeller shaft 15 and movable in the fore-and-aft direction relative to the propeller shaft 15. A shift plunger 22 is a member that moves the dog clutch 21, and is attached inside the front end of the propeller shaft 15 so as to be movable in the fore-and-aft direction relative to the propeller shaft 15. The electric propulsion unit 1 is also provided with a shift actuator 23 that controls the movement of the dog clutch 21, and a shift rod 24 that transmits the power of the shift actuator 23 to the shift plunger 22. The power of the shift actuator 23 is transmitted to the dog clutch 21 via the shift rod 24 and the shift plunger 22, causing the dog clutch 21 to move forward or backward. When the dog clutch 21 moves forward, the dog clutch 21 and the forward gear 19 engage with each other, and the rotation of the forward gear 19 is thereby transmitted to the propeller shaft 15.On the other hand, when the dog clutch 21 moves rearward, the dog clutch 21 and the reverse gear 20 engage with each other, thereby transmitting the rotation of the reverse gear 20 to the propeller shaft 15.

[0021] When the motor 3 is driven, the rotation of the output shaft 4 of the motor 3 is transmitted to the forward gear 19 and the reverse gear 20 via the drive gear 12, the driven gear 13, the drive shaft 14, and the transmission gear 18 in this order. When the dog clutch 21 is moving forward, the rotation of the forward gear 19 is transmitted to the propeller shaft 15, causing the propeller shaft 15 and the propeller 16 to rotate in the forward direction. The forward rotation of the propeller 16 generates a propulsive force that moves the boat forward. On the other hand, when the dog clutch 21 is moving rearward, the rotation of the reverse gear 20 is transmitted to the propeller shaft 15, causing the propeller shaft 15 and the propeller 16 to rotate in the reverse direction. The reverse rotation of the propeller 16 generates a propulsive force that moves the boat backward.

[0022] 3 and 4, the electric propulsion unit 1 also includes a reduction gear case 25 that houses the reduction gear 11 and the upper part of the drive shaft 14. The reduction gear case 25 is located below the motor 3 and attached to the motor 3. The electric propulsion unit 1 also includes a lower case 27 that houses the lower part of the drive shaft 14, the front part of the propeller shaft 15, and the rotation transmission mechanism 17. The lower case 27 is located below the reduction gear case 25 and attached to the reduction gear case 25.

[0023] 1 , the electric propulsion unit 1 also includes an attachment mechanism 30 that attaches the electric propulsion unit main body 2 to the vessel. The attachment mechanism 30 includes a pair of left and right clamp brackets 31 that attach the electric propulsion unit main body 2 to the transom 101 of the vessel, a pilot shaft 32 that is an axis that rotates the electric propulsion unit main body 2 in the left-right direction relative to the vessel, a swivel bracket 33 that rotatably supports the pilot shaft 32, a tilt shaft 34 that connects the clamp brackets 31 and the swivel bracket 33 to each other, an upper mount 35 that connects the upper end of the pilot shaft 32 to the electric propulsion unit main body 2 to each other, and a lower mount 36 that connects the lower end of the pilot shaft 32 to the electric propulsion unit main body 2 to each other.

[0024] The pair of left and right clamp brackets 31 and swivel bracket 33 are disposed at the front of the upper part of the electric propulsion unit body 2. The swivel bracket 33 is disposed between the pair of clamp brackets 31. The swivel bracket 33 can rotate up and down relative to each clamp bracket 31, with the tilt shaft 34 serving as the rotation axis. This allows the electric propulsion unit body 2 to rotate up and down relative to the vessel (tilt up and tilt down).

[0025] The pilot shaft 32 extends in the vertical direction, and a front portion of the upper mount 35 is fixed to the upper end of the pilot shaft 32. The rear portion of the upper mount 35 is attached to the front portion of the upper portion of the electric propulsion body 2, specifically the front portion of the inverter mounting member 10. The front portion of the lower mount 36 is fixed to the lower end of the pilot shaft 32. The rear portion of the lower mount 36 is attached to the front portion of the lower portion of the upper portion of the electric propulsion body 2, specifically the front portion of the reduction gear case 25. In this way, the electric propulsion body 2 is connected to the pilot shaft 32 by having two portions of its upper portion that are separated from each other in the vertical direction supported by the upper mount 35 and the lower mount 36, and the pilot shaft 32 is connected to the swivel bracket 33 by being supported by the swivel bracket 33.

[0026] (cooling device) 5 shows the configuration of a cooling device 41 in the electric propulsion 1 of this embodiment. The cooling device 41 is a liquid-cooling type cooling device that cools devices that require cooling and are provided in the electric propulsion 1. The devices that require cooling and are provided in the electric propulsion 1 are the motor 3, the inverter 6, and the reduction gear 11.

[0027] As shown in FIG. 5, the cooling device 41 includes a direct cooling system 42 and an indirect cooling system 60. The direct cooling system 42 is a system that cools equipment requiring cooling or a refrigerant by directly exchanging heat with water (e.g., seawater) outside the electric propulsion device 1. The indirect cooling system 60 is a system that cools equipment requiring cooling by exchanging heat with the refrigerant cooled in the direct cooling system. The refrigerant is, for example, a coolant such as LLC. Note that the direct cooling system 42 is a specific example of a "first cooling system," and the indirect cooling system 60 is a specific example of a "second cooling system."

[0028] (Direct cooling system) 5, the direct cooling system 42 includes a water intake 43, a reduction gear cooling jacket 44, a heat exchanger 45, a water pump 46, a supply passage, a discharge passage 55, a discharge space 56, and a drain port 57. The supply passage has cooling water passages 51-53.

[0029] FIG. 6 shows an enlarged view of the water intake 43, the water pump 46, the reduction gear cooling jacket 44, the heat exchanger 45, and the like in the electric propulsion device 1 in FIG.

[0030] 6, water intake 43 is an opening for taking water from outside the electric propulsion device 1 into the electric propulsion device 1. Water intake 43 is provided in a portion of the electric propulsion device 1 that is submerged under the water surface, for example, in a portion of the front part of the lower case 27 below the anti-cavitation plate 28.

[0031] The reduction gear cooling jacket 44 is a mechanism that cools the reduction gear 11 using cooling water. The reduction gear cooling jacket 44 is configured with a cooling water flow path that passes through a location adjacent to the reduction gear 11. The reduction gear cooling jacket 44 is disposed below the reduction gear 11 within the reduction gear case 25. The reduction gear cooling jacket 44 is also located below the motor 3. The reduction gear cooling jacket 44 is also located behind the drive shaft 14. The reduction gear cooling jacket 44 is a specific example of a "transmission mechanism cooling jacket."

[0032] The heat exchanger 45 is a device that uses water outside the electric propulsion 1 as cooling water to cool the refrigerant. The heat exchanger 45 includes an internal cooling water passage through which the cooling water flows and an internal refrigerant passage through which the refrigerant flows. The internal cooling water passage and the internal refrigerant passage are independent of each other, but are located very close to each other so that heat exchange can occur between the cooling water flowing in the internal cooling water passage and the refrigerant flowing in the internal refrigerant passage. As shown in FIG. 7 , the heat exchanger 45 has a cylindrical or polygonal prism-like outer shape with an axial dimension Lx greater than a radial dimension Ly. As shown in FIG. 1 , the heat exchanger 45 is disposed behind the motor 3 so that the axial direction of the heat exchanger 45 is aligned with the vertical direction of the electric propulsion 1. The heat exchanger 45 is disposed below the upper end of the swivel bracket 33. The heat exchanger 45 is located between the upper mount 35 and the lower mount 36 in the vertical direction.

[0033] The water pump 46 is a pump that sends water outside the electric propulsion unit 1 that is taken into the electric propulsion unit 1 through the water intake 43 as cooling water to the reduction gear cooling jacket 44 and the heat exchanger 45. The water pump 46 is, for example, a rotary variable displacement pump. As shown in FIG. 6 , the water pump 46 has an impeller 47 and a pump case 48 that houses the impeller 47. The impeller 47 is fixed to the drive shaft 14 and rotates integrally with the drive shaft 14. The pump case 48 is attached to the upper surface of the lower case 27, for example.

[0034] The supply passage is a passage that supplies water outside the electric propulsion unit 1 as cooling water to the reduction gear cooling jacket 44 and the heat exchanger 45. The supply passage has a cooling water passage 51 that connects the water intake 43 and the suction port of the water pump 46, a cooling water passage 52 that connects the discharge port 48A of the water pump 46 and the reduction gear cooling jacket 44, and a cooling water passage 53 that connects the reduction gear cooling jacket 44 and the heat exchanger 45.

[0035] The cooling water passage 51 is formed, for example, by a hole extending in the vertical direction and formed in the lower case 27. The cooling water passage 52 is formed, for example, by a tubular member attached to a part inside the reduction gear case 25. The cooling water passages 51 and 52 correspond to cooling water passages that connect the water intake 43 and the reduction gear cooling jacket 44.

[0036] The cooling water passage 53 is formed by, for example, a hose or a pipe. As can be seen from FIGS. 2 and 3 , the cooling water passage 53 is disposed outside the reduction gear case 25. An inlet end of the cooling water passage 53 is connected to the rear of the reduction gear cooling jacket 44. Specifically, a connection port 54 that communicates with the interior of the reduction gear cooling jacket 44 opens on the rear surface of the reduction gear case 25. An inlet end of the cooling water passage 53 is connected to this connection port 54. An outlet end of the cooling water passage 53 is connected to an inlet of an internal cooling water flow path provided in the lower part of the heat exchanger 45. The cooling water passage 53 extends rearward from the connection port 54, then bends upward, and then extends upward to reach the lower part of the heat exchanger 45.

[0037] The discharge passage 55 is a passage that carries the cooling water that has flowed through the internal cooling water flow path of the heat exchanger 45 to a drain port 57. As shown in FIGS. 1 and 2 , the discharge passage 55 is formed, for example, by a hose or a pipe. An inlet end of the discharge passage 55 is connected to an outlet of the internal cooling water flow path that is provided in the lower part of the heat exchanger 45. As shown in FIG. 3 , a discharge space 56 is provided from the rear part of the lower part of the reduction gear case 25 to the rear part of the lower case 27. As shown in FIG. 1 , a discharge space inlet 56A that communicates with the inside of the discharge space 56 opens on the left side of the reduction gear case 25. An outlet end of the discharge passage 55 is connected to the discharge space inlet 56A and communicates with the inside of the discharge space 56 via the discharge space inlet 56A.

[0038] The drain outlet 57 is an opening for discharging the cooling water that has flowed through the heat exchanger 45 to the outside of the electric propulsion device 1. The drain outlet 57 is formed, for example, inside the hub of the propeller 16. The drain outlet 57 is in communication with the inside of the discharge space 56.

[0039] In FIG. 6 , when the drive shaft 14 rotates and the water pump 46 is driven, water outside the electric propulsion unit 1 is taken into the electric propulsion unit 1 through the water intake 43 and flows through the cooling water passage 51 as cooling water, is sucked into the water pump 46, and is then discharged from the discharge port 48A of the water pump 46. The cooling water discharged from the discharge port 48A of the water pump 46 flows through the cooling water passage 52 and then flows through the reduction gear cooling jacket 44. The cooling water flowing through the reduction gear cooling jacket 44 cools the reduction gear 11. After flowing through the reduction gear cooling jacket 44, the cooling water flows through the cooling water passage 53 and then flows through the internal cooling water passage of the heat exchanger 45. The cooling water flowing through the internal cooling water passage of the heat exchanger 45 cools the refrigerant circulating through the circulation passage of the indirect cooling system 60. After flowing through the internal cooling water flow path of the heat exchanger 45, the cooling water flows through the discharge passage 55 (see Figure 1), then through the discharge space 56 (see Figure 3), and is then discharged outside the electric propulsion device 1 through the drain outlet 57.

[0040] (Indirect cooling system) 5, the indirect cooling system 60 includes a motor cooling jacket 61, an inverter cooling jacket 62, a refrigerant pump 63, a degassing tank 64, and a circulation passage. The circulation passage has refrigerant passages 71-76.

[0041] The motor cooling jacket 61 is a mechanism that cools the motor 3 using a refrigerant. As shown in FIG. 3 , the motor cooling jacket 61 is provided on the motor 3. For example, the motor cooling jacket 61 is composed of flow paths formed in the motor case 5 of the motor 3. The flow paths that make up the motor cooling jacket 61 are formed over a wide area of ​​the motor case 5. For example, the flow paths are formed around the entire circumference of the motor case 5, extending from one axial end to the other axial end of the motor case 5. One end of the motor cooling jacket 61 is provided with an inlet 61A, which is a port that connects the inside of the motor cooling jacket 61 to the outside of the motor cooling jacket 61 and allows the refrigerant to flow into the motor cooling jacket 61. The inlet 61A opens to the rear of the lower part of the motor case 5. The other end of the motor cooling jacket 61 is provided with an outlet 61C, which is a port that connects the inside of the motor cooling jacket 61 to the outside of the motor cooling jacket 61 and allows the refrigerant to flow out of the motor cooling jacket 61 after flowing through the motor cooling jacket 61. The outlet 61C opens at the left rear portion of the upper surface 5A of the motor case 5, as will be described later with reference to FIG.

[0042] The inverter cooling jacket 62 is a mechanism that cools the inverter 6 using a refrigerant. As shown in FIG. 3 , the inverter cooling jacket 62 is provided on the inverter 6. For example, the inverter cooling jacket 62 is disposed in a lower rear portion of the inverter 6, positioned below the rear portion of the inverter main body 7. Specifically, the inverter cooling jacket 62 is configured by a flow path formed in a lower rear portion of the inverter case 8. The flow path extends from the left end to the right end of the inverter case 8. One end of the inverter cooling jacket 62 is provided with an inlet 62A, which is a port that connects the inside of the inverter cooling jacket 62 with the outside of the inverter cooling jacket 62 and allows the refrigerant to flow into the inverter cooling jacket 62. The inlet 62A opens to the left end portion of the lower surface 8A of the rear portion of the inverter case 8, as will be described later with reference to FIG. 8 . The other end of the inverter cooling jacket 62 is provided with an outlet, which is a port that connects the inside of the inverter cooling jacket 62 with the outside of the inverter cooling jacket 62 and allows the refrigerant, having flowed through the inverter cooling jacket 62, to flow out of the inverter cooling jacket 62. Although not shown in detail, the outlet is open on the right side of the lower rear part of the inverter case 8.

[0043] The refrigerant pump 63 is a pump that circulates the refrigerant within the circulation passage. The refrigerant pump 63 is an electric pump, and is driven, for example, by a dedicated motor for the refrigerant pump 63, separate from the motor 3. As shown in FIG. 1 , the refrigerant pump 63 is disposed above the heat exchanger 45. The refrigerant pump 63 is also disposed behind the inverter 6. The refrigerant pump 63 is attached to the rear of the inverter 6. The refrigerant pump 63 can adjust the flow rate of the refrigerant by, for example, changing the rotation speed of the dedicated motor for the refrigerant pump 63. This allows the temperature of the refrigerant to be controlled.

[0044] The degassing tank 64 is a tank that has the function of separating gas from the refrigerant. Specifically, the degassing tank 64 has the function of releasing bubbles that are generated in the refrigerant due to heat or the like, and the function of acting as a reserve tank that absorbs increases or decreases in the amount of refrigerant due to thermal expansion or aging of the refrigerant. The degassing tank 64 is disposed above the inverter 6 and attached to the inverter 6. Specifically, the inverter case 8 is provided with a plurality of degassing tank mounting portions 9 that protrude upward from its top surface. The degassing tank 64 is attached to the upper ends of these degassing tank mounting portions 9 using connecting members such as bolts.

[0045] The circulation passage is a passage for circulating refrigerant between the heat exchanger 45 and the motor cooling jacket 61 and the inverter cooling jacket 62. In the indirect cooling system 60 of this embodiment, the heat exchanger 45, the motor cooling jacket 61, and the inverter cooling jacket 62 are connected in series, in this order, via the circulation passage. The circulation passage includes a refrigerant passage 71 connecting the heat exchanger 45 and the motor cooling jacket 61, a refrigerant passage 72 connecting the motor cooling jacket 61 and the inverter cooling jacket 62, a refrigerant passage 73 connecting the inverter cooling jacket 62 and a refrigerant passage connection 77, a refrigerant passage 74 connecting the refrigerant passage connection 77 and the refrigerant pump 63, a refrigerant passage 75 connecting the refrigerant pump 63 and the heat exchanger 45, and a refrigerant passage 76 connecting the refrigerant passage connection 77 and the degassing tank 64.

[0046] 1 and 2, the refrigerant passage 71 extends from the upper left side of the heat exchanger 45 to the lower rear side of the motor 3. The refrigerant passage 71 is formed, for example, by a hose or a pipe. The inlet end of the refrigerant passage 71 is connected to an outlet of the internal refrigerant flow path that opens on the upper left surface of the heat exchanger 45. The outlet end of the refrigerant passage 71 is connected to an inlet 61A (see FIG. 4) of the motor cooling jacket 61 that opens on the lower rear part of the motor case 5.

[0047] The refrigerant passage 72 is provided in a section extending from the upper left rear of the motor case 5 to the lower left rear of the inverter case 8. FIG. 8 shows a cross section of the upper left rear of the motor 3 and the lower left rear of the inverter 6 in the electric propulsion device 1 taken along section line XIII-XIII in FIG. 2. As shown in FIG. 8, an outlet end portion (terminal portion) 61B of the flow path constituting the motor cooling jacket 61 is formed in the upper left rear of the motor case 5. This outlet end portion 61B extends vertically, and its upper end opens to the left rear of the upper surface 5A of the motor case 5 (the upper surface of the motor 3). The opening at the upper end of this outlet end portion 61B is the outlet port 61C of the motor cooling jacket 61. Meanwhile, a cylindrical portion 62B protruding downward from the left end portion of the lower surface 8A of the rear of the inverter case 8 is provided. The inside of the cylindrical portion 62B is in communication with the interior of the inverter cooling jacket 62. Furthermore, an opening on the lower end side of the cylindrical portion 62B serves as an inlet 62A of the inverter cooling jacket 62. When the electric propulsion device 1 is viewed from above, at least a portion of the inlet 62A of the inverter cooling jacket 62 overlaps with the outlet 61C of the motor cooling jacket 61. Furthermore, the refrigerant passage 72 is configured, for example, by a linear hole that passes through the left rear portion of the inverter mounting member 10 in the vertical direction. A lower end (inlet end) of the refrigerant passage 72 is connected to the outlet 61C of the motor cooling jacket 61, and an upper end (outlet end) of the refrigerant passage 72 is connected to the inlet 62A of the inverter cooling jacket 62.

[0048] As shown in FIG. 2, refrigerant passage 73 is disposed to the rear right of inverter 6. Refrigerant passage 73 is formed, for example, by a hose or a pipe. An inlet end of refrigerant passage 73 is connected to an outlet of inverter cooling jacket 62, which opens on the right surface of the lower rear part of inverter case 8. An outlet end of refrigerant passage 73 is connected to refrigerant passage connection part 77. Refrigerant passage connection part 77 connects the outlet end of refrigerant passage 73, the inlet end of refrigerant passage 74, and the lower end of refrigerant passage 76 to one another, and is formed, for example, by a T-joint.

[0049] The refrigerant passage 74 is disposed to the right of the refrigerant pump 63. The refrigerant passage 74 is formed, for example, by a pipe. An inflow end of the refrigerant passage 74 is connected to a refrigerant passage connection part 77. An outflow end of the refrigerant passage 74 is connected to a suction port of the refrigerant pump 63 provided on the right surface of the refrigerant pump 63.

[0050] The refrigerant passage 75 extends from the lower right side of the refrigerant pump 63 to the lower right side of the heat exchanger 45. The refrigerant passage 75 is formed, for example, by a hose or a pipe. The inlet end of the refrigerant passage 75 is connected to the discharge port of the refrigerant pump 63, which is provided at the lower right side of the refrigerant pump 63. The outlet end of the refrigerant passage 75 is connected to the inlet of an internal refrigerant flow path that opens to the lower right side of the heat exchanger 45. The refrigerant passages 73, 74, and 75 correspond to refrigerant passages that connect the inverter cooling jacket 62 and the heat exchanger 45.

[0051] The refrigerant passage 76 is disposed above the right rear portion of the inverter 6 and behind the right portion of the degassing tank 64. The refrigerant passage 76 is formed, for example, by a hose or a pipe. The lower end of the refrigerant passage 76 is connected to a refrigerant passage connection portion 77. The upper end of the refrigerant passage 76 is connected to a connection port provided in the right rear portion of the degassing tank 64.

[0052] When the refrigerant pump 63 is driven, the refrigerant cooled by the heat exchanger 45 flows out from the outlet of the internal refrigerant flow path of the heat exchanger 45, flows through the refrigerant passage 71, and then flows through the motor cooling jacket 61. The refrigerant flows through the motor cooling jacket 61, thereby cooling the motor 3. After flowing through the motor cooling jacket 61, the refrigerant flows through the refrigerant passage 72 and then through the inverter cooling jacket 62. The refrigerant flows through the inverter cooling jacket 62, thereby cooling the inverter main body 7. After flowing through the inverter cooling jacket 62, the refrigerant flows sequentially through the refrigerant passage 73, the refrigerant passage connection portion 77, the refrigerant passage 74, the refrigerant pump 63, and the refrigerant passage 75, before flowing into the internal refrigerant flow path of the heat exchanger 45 from the inlet of the internal refrigerant flow path. The refrigerant, which has been heated by the heat of the motor 3 and the inverter 6, is cooled in the heat exchanger 45 by cooling water taken in from outside the electric propulsion unit 1.

[0053] A refrigerant is stored in the degassing tank 64. Air bubbles in the refrigerant move into the degassing tank 64 through the refrigerant passage 76 and are released into the atmosphere, for example, through a gas vent passage formed in the degassing tank 64. When the amount of refrigerant flowing through the circulation passage becomes low, the cap 65 of the degassing tank 64 can be removed and refrigerant can be injected into the degassing tank 64 to replenish the refrigerant.

[0054] As described above, the cooling device 41 provided in the electric propulsion 1 according to the first embodiment of the present invention includes a heat exchanger 45 that cools the refrigerant using water outside the electric propulsion 1, a supply passage that supplies water outside the electric propulsion 1 to the heat exchanger 45, and a direct cooling system that cools the refrigerant by exchanging heat with the water outside the electric propulsion 1, a motor cooling jacket 61 that cools the motor 3 using the refrigerant, and an indirect cooling system 60 that includes a circulation passage that circulates the refrigerant between the heat exchanger 45 and the motor cooling jacket 61, and cools the motor 3 by exchanging heat with the refrigerant cooled in the direct cooling system. In the cooling device 41 configured as described above, when cooling the motor 3, water outside the electric propulsion 1 does not flow through the motor cooling jacket 61. In other words, seawater does not flow through the motor cooling jacket 61. This prevents corrosion of the motor cooling jacket 61 due to seawater. This suppresses corrosion of the motor cooling jacket 61.

[0055] In the electric propulsion unit 1 of this embodiment, the motor 3 and heat exchanger 45 are disposed below the upper end of the swivel bracket 33. This configuration makes it possible to lower the center of gravity of the electric propulsion unit 1 and improve the stability of the installation of the electric propulsion unit 1 on the boat. It also makes it possible to prevent the electric propulsion unit 1 from protruding upward, preventing the electric propulsion unit 1 from obstructing the view behind the boat.

[0056] Furthermore, in the electric propulsion unit 1 of this embodiment, the heat exchanger 45 is located between the upper mount 35 and the lower mount 36 in the vertical direction. With this configuration, the center of gravity of the electric propulsion unit 1 can be located between the upper mount 35 and the lower mount 36 in the vertical direction. By lowering the center of gravity of the electric propulsion unit 1 in this way, the stability of the installation of the electric propulsion unit 1 on the boat can be improved.

[0057] Furthermore, in the electric propulsion unit 1 of this embodiment, the heat exchanger 45 has a cylindrical or polygonal prism-like outer shape with its axial dimension greater than its radial dimension. The heat exchanger 45 is disposed behind the motor 3 so that the axial direction of the heat exchanger 45 is aligned with the vertical direction of the electric propulsion unit 1. This configuration allows the center of gravity of the heat exchanger 45 to be closer to the vessel, and therefore the center of gravity of the electric propulsion unit 1 to be closer to the vessel, thereby improving the stability of the installation of the electric propulsion unit 1 on the vessel.

[0058] Furthermore, the indirect cooling system 60 of the cooling device 41 provided in the electric propulsion 1 of this embodiment includes a motor cooling jacket 61 that uses a refrigerant to cool the motor 3, an inverter cooling jacket 62 that uses a refrigerant to cool the inverter 6, and a circulation passage that circulates the refrigerant between the heat exchanger 45 and the motor cooling jacket 61 and the inverter cooling jacket 62. With this configuration, when cooling the motor 3 and the inverter 6, water outside the electric propulsion 1 does not flow through the motor cooling jacket 61 or the inverter cooling jacket 62. In other words, seawater does not flow through the motor cooling jacket 61 or the inverter cooling jacket 62. This prevents corrosion of the motor cooling jacket 61 and the inverter cooling jacket 62 by seawater. This prevents corrosion of the motor cooling jacket 61 and the inverter cooling jacket 62.

[0059] Furthermore, in the electric propulsion device 1 of this embodiment, the heat exchanger 45 is disposed rearward of the motor 3, the inverter 6 is disposed above the motor 3, and the inverter cooling jacket 62 is disposed rearward of the inverter 6. This configuration makes it possible to shorten the distance between the motor 3 and the heat exchanger 45, the distance between the motor 3 and the inverter 6, the distance between the inverter cooling jacket 62 and the heat exchanger 45, and the distance between the inverter cooling jacket 62 and the motor 3. This makes it possible to shorten the circulation passage in the indirect cooling system 60. This makes it possible to reduce pressure loss caused by the refrigerant flowing through the circulation passage, and to smooth the flow of the refrigerant in the indirect cooling system 60.

[0060] Furthermore, in the electric propulsion 1 of this embodiment, the indirect cooling system 60 of the cooling device 41 includes a degassing tank 64 connected to the circulation passage, the inverter 6 is disposed above the motor 3, and the degassing tank 64 is disposed above the inverter 6. With this configuration, the degassing tank 64 can be disposed at a high position in the electric propulsion 1. This makes it easier for bubbles in the refrigerant to be released into the atmosphere.

[0061] Furthermore, in the cooling device 41 provided in the electric propulsion unit 1 of this embodiment, the indirect cooling system 60 includes a refrigerant pump 63 that circulates the refrigerant within a circulation passage, and the refrigerant pump 63 is disposed above the heat exchanger 45. With this configuration, a person performing maintenance on the electric propulsion unit 1 can easily tilt up the electric propulsion unit 1 and perform maintenance on the refrigerant pump 63.

[0062] Furthermore, in the cooling device 41 provided in the electric propulsion 1 of this embodiment, the direct cooling system 42 includes a reduction gear cooling jacket 44 that cools the reduction gear 11 using water outside the electric propulsion 1, and the supply passage in the direct cooling system 42 is a passage that supplies water outside the electric propulsion 1 to the heat exchanger 45 and the reduction gear cooling jacket 44. With this configuration, it is possible to use water outside the electric propulsion 1 to cool not only the refrigerant but also the reduction gear 11.

[0063] Furthermore, in the electric propulsion 1 of this embodiment, the heat exchanger 45 is disposed rearward of the motor 3, the reduction gear cooling jacket 44 is disposed below the motor 3, the inlet end of a cooling water passage 53 connecting the reduction gear cooling jacket 44 and the heat exchanger 45 is connected to the rear part of the reduction gear cooling jacket 44, and the outlet end of the cooling water passage 53 is connected to the lower part of the heat exchanger 45. This configuration makes it possible to shorten the cooling water passage 53. Therefore, it is possible to reduce pressure loss caused by the cooling water flowing through the cooling water passage 53, and to smooth the flow of cooling water in the direct cooling system 42.

[0064] Furthermore, in the electric propulsion device 1 of this embodiment, the inverter 6 is disposed above the motor 3, the outlet 61C of the motor cooling jacket 61 is disposed on the upper surface 5A of the motor case 5 (the upper surface of the motor 3), and the inlet 62A of the inverter cooling jacket 62 is disposed on the lower surface 8A of the inverter case 8 (the lower surface of the inverter 6). This configuration makes it possible to shorten the refrigerant passage 72 connecting the outlet 61C of the motor cooling jacket 61 and the inlet 62A of the inverter cooling jacket 62. This makes it possible to reduce pressure loss caused by the refrigerant flowing through the refrigerant passage 72, thereby enabling the refrigerant to circulate more smoothly in the indirect cooling system 60.

[0065] Furthermore, when the electric propulsion device 1 of this embodiment is viewed from above, at least a portion of the inlet 62A of the inverter cooling jacket 62 overlaps with the outlet 61C of the motor cooling jacket 61. This configuration allows the extension shape of the refrigerant passage 72 to be straight or close to straight, which can promote smoother flow of the refrigerant in the indirect cooling system 60. [Example]

[0066] Figure 9(A) shows an electric propulsion device 81 according to a second embodiment of the present invention as seen from the left. Figure 9(B) shows the lower part of the electric propulsion device 81 as seen from the rear. Figure 10 shows the configuration of a cooling device 85 provided in the electric propulsion device 81 according to the second embodiment of the present invention. Note that in the electric propulsion device 81 according to the second embodiment of the present invention, the same components as those in the electric propulsion device 1 according to the first embodiment of the present invention are designated by the same reference numerals, and their description will be simplified or omitted.

[0067] 10, compared to cooling device 41 according to the first embodiment of the present invention, cooling device 85 according to the second embodiment of the present invention additionally includes a refrigerant reservoir 87 as a component of indirect cooling system 86. Refrigerant reservoir 87 stores the refrigerant circulating in the circulation passage of indirect cooling system 86.

[0068] As shown in FIG. 9(A), in electric propulsion unit 81, refrigerant storage unit 87 is provided in a portion extending from the rear of the lower portion of reduction gear case 82 to the rear of lower case 83. Specifically, as shown in FIG. 3, in electric propulsion unit 1 of the first embodiment of the present invention, discharge space 56 is provided in a portion extending from the rear of the lower portion of reduction gear case 25 to the rear of lower case 27. In electric propulsion unit 81 of the second embodiment of the present invention, as shown in FIG. 9(A), the portion corresponding to discharge space 56 in electric propulsion unit 1 of the first embodiment of the present invention is divided into two, for example, front and rear, with refrigerant storage unit 87 provided in the front portion of the two halves and discharge space 84 provided in the rear portion of the two halves. Note that reduction gear case 82 and lower case 83 are specific examples of "cases."

[0069] Furthermore, as can be seen from a comparison between Figures 1 and 9(A), in the circulation passage of indirect cooling system 86 of cooling device 85 according to the second embodiment of the present invention, refrigerant passage 71 connecting heat exchanger 45 and motor cooling jacket 61 in indirect cooling system 60 of cooling device 41 according to the first embodiment of the present invention is replaced with refrigerant passage 91 connecting heat exchanger 45 and refrigerant reservoir 87, and refrigerant passage 92 connecting refrigerant reservoir 87 and motor cooling jacket 61.

[0070] An inlet end of the refrigerant passage 91 is connected to an outlet of the internal refrigerant flow path that opens to the left surface of the upper part of the heat exchanger 45. A refrigerant storage inlet that communicates with the refrigerant storage portion 87 opens to the left surface of the reduction gear case 25. An outlet end of the refrigerant passage 91 is connected to the refrigerant storage inlet.

[0071] A refrigerant reservoir outlet that communicates with the refrigerant reservoir 87 is opened on the left side of the reduction gear case 25. The inlet end of the refrigerant passage 92 is connected to the refrigerant reservoir outlet. The outlet end of the refrigerant passage 92 is connected to an inlet 61A of the motor cooling jacket 61 that opens at the rear of the lower part of the motor case 5.

[0072] In an indirect cooling system 86 of a cooling device 85 according to a second embodiment of the present invention, a refrigerant reservoir 87 is filled with refrigerant. When a refrigerant pump 63 is driven, the refrigerant in the refrigerant reservoir 87 flows into a refrigerant passage 92 and then flows through the motor cooling jacket 61. The refrigerant flows through the motor cooling jacket 61, thereby cooling the motor 3. After flowing through the motor cooling jacket 61, the refrigerant flows through a refrigerant passage 72 and then through the inverter cooling jacket 62. The refrigerant flows through the inverter cooling jacket 62, thereby cooling the inverter main body 7. After flowing through the inverter cooling jacket 62, the refrigerant flows sequentially through a refrigerant passage 73, a refrigerant passage connection portion 77, a refrigerant passage 74, a refrigerant pump 63, and a refrigerant passage 75, before flowing into the internal refrigerant flow path of the heat exchanger 45. The refrigerant, which has been heated by the heat of the motor 3 and the inverter 6, is cooled in the heat exchanger 45. Furthermore, the refrigerant cooled in the heat exchanger 45 flows out from the outlet of the internal refrigerant flow path of the heat exchanger 45 , flows through the refrigerant passage 91 , and flows into the refrigerant reservoir 87 .

[0073] According to the cooling device 85 of the second embodiment of the present invention having such a configuration, the refrigerant can be stored in the refrigerant reservoir 87, thereby increasing the amount of refrigerant circulating in the circulation passage. This increases the heat capacity of the refrigerant. This stabilizes the cooling capacity of the motor 3 and the inverter 6 in the indirect cooling system 60. Specifically, for example, when the rotation speed of the motor 3 is extremely low and the boat is moving at an extremely slow speed, the rotation speed of the impeller 47 of the water pump 46 of the direct cooling system 42, which rotates integrally with the drive shaft 14, becomes extremely low. As a result, the flow rate of the cooling water from the water pump 46 decreases, resulting in a slight shortage of the supply of cooling water to the heat exchanger 45, which may reduce the cooling capacity of the heat exchanger 45. However, even if the cooling capacity of the heat exchanger 45 decreases, the large heat capacity of the refrigerant slows the decrease in the cooling capacity of the motor 3 and the inverter 6. This stabilizes the cooling capacity of the motor 3 and the inverter 6 in the indirect cooling system 60.

[0074] In the above embodiments, the refrigerant is circulated through the heat exchanger 45, the motor cooling jacket 61, and the inverter cooling jacket 62 in this order in the indirect cooling system 60 (86). However, the refrigerant may be circulated through the heat exchanger 45, the inverter cooling jacket 62, and the motor cooling jacket 61 in this order by, for example, reversing the rotation direction of the impeller of the refrigerant pump 63 and reversing the flow direction of the refrigerant in the circulation passage.

[0075] In addition, in the above-described embodiments, the indirect cooling system 60 (86) cools the motor 3 and the inverter 6, but the present invention is not limited to this. For example, the indirect cooling system 60 (86) may cool only the motor 3 or only the inverter 6, or additional equipment other than the motor 3 and the inverter 6 may be added to the equipment to be cooled in the indirect cooling system 60 (86).

[0076] Furthermore, in the second embodiment described above, in electric propulsion 81, refrigerant reservoir 87 is provided in a section extending from the rear of the lower part of reduction gear case 82 to the rear of lower case 83, but the location where the refrigerant reservoir is provided in the electric propulsion of the present invention is not limited. For example, the area in which the refrigerant reservoir is provided may be limited to within reduction gear case 82, which accommodates the upper part of drive shaft 14, or the area in which the refrigerant reservoir is provided may be limited to within lower case 83, which accommodates the lower part of drive shaft 14.

[0077] Furthermore, although the electric propulsion unit 1 (81) in each of the above embodiments is an outboard motor, the present invention can also be applied to other types of electric marine propulsion units, such as an outboard inboard motor.

[0078] Furthermore, the present invention may be modified as appropriate within the scope of the claims and the spirit 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]

[0079] 1, 81 Electric propulsion machine 2 Electric propulsion unit 3 motors 5 Motor case 5A top 6 inverters 8 Inverter case 8A Bottom 11 Reduction gear (first transmission mechanism) 14 Drive shaft 15 propeller shaft 16 propellers 17 Rotation transmission mechanism (second transmission mechanism) 25, 82 Reduction gear case 27, 83 Lower case 30 Mounting mechanism 33 Swivel bracket 35 Upper Mount 36 Lower Mount 41, 85 Cooling device 42 Direct cooling system (first cooling system) 43 Water Intake 44 Reduction gear cooling jacket (transmission mechanism cooling jacket) 45 Heat exchanger 51 Cooling water passage (supply passage) 52 Cooling water passage (supply passage) 53 Cooling water passage (supply passage) 60, 86 Indirect cooling system (second cooling system) 61 Motor cooling jacket 61C Outlet (Port) 62 Inverter cooling jacket 62A Inlet (Port) 63 Refrigerant pump 64 Degas Tank 71 Refrigerant passage (circulation passage) 72 Refrigerant passage (circulation passage) 73 Refrigerant passage (circulation passage) 74 Refrigerant passage (circulation passage) 75 Refrigerant passage (circulation passage) 76 Refrigerant passage (circulation passage) 87 Refrigerant reservoir 91 Refrigerant passage (circulation passage) 92 Refrigerant passage (circulation passage)

Claims

1. An electric propulsion device including a motor that rotates a propeller and a cooling device that cools the motor, the cooling device comprises a first cooling system and a second cooling system; The first cooling system includes: a heat exchanger that uses water outside the electric propulsion device as cooling water to cool a refrigerant; a supply passage that supplies water outside the electric propulsion device to the heat exchanger as cooling water, The second cooling system includes: a motor cooling jacket provided on the motor and configured to cool the motor using the refrigerant; an electric propulsion comprising: a circulation passage for circulating the coolant between the heat exchanger and the motor cooling jacket;

2. an electric propulsion unit body including the motor, a propeller shaft disposed below the motor and having the propeller provided thereon, and a drive shaft extending in the vertical direction between the motor and the propeller shaft; a mounting mechanism for mounting the electric propulsion unit body to a vessel, the mounting mechanism has a swivel bracket that supports the electric propulsion unit body so that it can rotate laterally relative to the vessel, The electric propulsion device according to claim 1, wherein the motor and the heat exchanger are disposed below an upper end of the swivel bracket.

3. the attachment mechanism has two mounts that respectively connect two portions of the upper portion of the electric propulsion body that are spaced apart in the vertical direction to the swivel bracket; 3. The electric propulsion device according to claim 2, wherein the heat exchanger is located between the two mounts in the vertical direction.

4. The heat exchanger has a cylindrical or polygonal columnar outer shape in which the axial dimension is larger than the radial dimension, The electric propulsion device according to claim 1, wherein the heat exchanger is disposed behind the motor so that the axial direction of the heat exchanger is aligned with the up-down direction of the electric propulsion device.

5. an inverter for controlling the driving of the motor; The second cooling system includes: an inverter cooling jacket provided in the inverter and configured to cool the inverter using the refrigerant; The circulation passage is The electric propulsion device according to claim 1, wherein the coolant is circulated between the heat exchanger and the motor cooling jacket and between the heat exchanger and the inverter cooling jacket.

6. 6. The electric propulsion according to claim 5, wherein the circulation passage includes a first refrigerant passage connecting the heat exchanger and the motor cooling jacket, a second refrigerant passage connecting the motor cooling jacket and the inverter cooling jacket, and a third refrigerant passage connecting the inverter cooling jacket and the heat exchanger.

7. 6. The electric propulsion device according to claim 5, wherein the heat exchanger is disposed rearward of the motor, the inverter is disposed above the motor, and the inverter cooling jacket is disposed rearward of the inverter.

8. The second cooling system includes: a degassing tank connected to the circulation passage and configured to separate gas from the refrigerant; 6. The electric propulsion device according to claim 5, wherein the inverter is disposed above the motor, and the degassing tank is disposed above the inverter.

9. the second cooling system includes a refrigerant pump that circulates the refrigerant within the circulation passage; The electric propulsion device according to claim 1 , wherein the coolant pump is disposed above the heat exchanger.

10. a propeller shaft disposed below the motor and provided with the propeller; a drive shaft extending in the vertical direction between the motor and the propeller shaft; a case that houses an upper or lower portion of the drive shaft, The second cooling system includes: a refrigerant pump that circulates the refrigerant within the circulation passage; a refrigerant reservoir provided in the case and configured to store the refrigerant circulating in the circulation passage; the circulation passage includes a first refrigerant passage connecting the heat exchanger and the refrigerant reservoir, a second refrigerant passage connecting the refrigerant reservoir and the motor cooling jacket, and a third refrigerant passage connecting the motor cooling jacket and the heat exchanger, 2. The electric propulsion according to claim 1, wherein the coolant pump circulates the coolant so that the coolant flows from the heat exchanger to the coolant reservoir, then from the coolant reservoir to the motor cooling jacket, and then from the motor cooling jacket back to the heat exchanger.

11. A drive shaft, a first transmission mechanism that transmits rotation of the motor to the drive shaft; a propeller shaft provided with the propeller; a second transmission mechanism that transmits the rotation of the drive shaft to the propeller shaft, The first cooling system includes: a transmission mechanism cooling jacket that uses water outside the electric propulsion as cooling water to cool the first transmission mechanism, 2. The electric propulsion according to claim 1, wherein the supply passage is a passage that supplies water from outside the electric propulsion as cooling water to the heat exchanger and the transmission mechanism cooling jacket.

12. 12. The electric propulsion according to claim 11, wherein the supply passage includes a first cooling water passage that connects the transmission mechanism cooling jacket to a water intake that takes water from outside the electric propulsion into the electric propulsion as cooling water, and a second cooling water passage that connects the transmission mechanism cooling jacket to the heat exchanger.

13. 13. The electric propulsion according to claim 12, wherein the heat exchanger is disposed rearward of the motor, the transmission mechanism cooling jacket is disposed below the motor, one end of the second cooling water passage is connected to a rear portion of the transmission mechanism cooling jacket, and the other end of the second cooling water passage is connected to a lower portion of the heat exchanger.

14. the inverter is disposed above the motor; a port for communicating the inside of the motor cooling jacket with the outside of the motor cooling jacket is provided at each end of the motor cooling jacket, and one port of the motor cooling jacket is disposed on the upper surface of the motor; 6. The electric propulsion according to claim 5, wherein ports are provided at both ends of the inverter cooling jacket, respectively, to communicate the inside of the inverter cooling jacket with the outside of the inverter cooling jacket, and one of the ports of the inverter cooling jacket is located on a lower surface of the inverter.

15. 15. The electric propulsion according to claim 14, wherein, when the electric propulsion is viewed from above, at least a portion of the one port of the inverter cooling jacket overlaps with the one port of the motor cooling jacket.

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