Marine propulsion device

Abstract

A marine propulsion device includes a motor, a first transmission mechanism transmitting a rotation of the motor to a drive shaft, a second transmission mechanism transmitting a rotation of the drive shaft to a propeller shaft, an inverter controlling the motor, and a cooling device. The cooling device includes a motor water jacket cooling the motor, a transmission mechanism water jacket cooling the first transmission mechanism, an inverter water jacket cooling the inverter, and a distribution mechanism distributing and suppling a cooling water after flowing in the motor water jacket to the transmission mechanism water jacket and the inverter water jacket in parallel. The distribution mechanism includes a first distribution passage suppling the cooling water after flowing in the motor water jacket to the transmission mechanism water jacket, and a second distribution passage suppling the cooling water after flowing in the motor water jacket to the inverter water jacket.

Description

TECHNICAL FIELD

[0001] The present invention relates to a marine propulsion device including a motor as a power source for rotating a propeller.BACKGROUND ART

[0002] There is known a marine propulsion device that includes a motor (electric motor) as a power source for rotating a propeller, a drive shaft, a transmission mechanism (for example, a speed reducer) that transmits rotation of the motor to the drive shaft, and an inverter that controls driving of the motor (see, for example, JP2005-162055A).SUMMARY OF INVENTION

[0003] According to one advantageous aspect of the invention, there is provided a marine propulsion device including: a motor; a drive shaft; a first transmission mechanism configured to transmit a rotation of the motor to the drive shaft; a propeller shaft provided with a propeller; a second transmission mechanism configured to transmit a rotation of the drive shaft to the propeller shaft; an inverter configured to control driving of the motor; and a cooling device, in which the cooling device includes a motor water jacket configured to cool the motor, a transmission mechanism water jacket configured to cool the first transmission mechanism, an inverter water jacket configured to cool the inverter, a supply passage configured to supply a cooling water to the motor water jacket, and a distribution mechanism configured to distribute and supply the cooling water after flowing in the motor water jacket to the transmission mechanism water jacket and the inverter water jacket in parallel, and the distribution mechanism includes a first distribution passage configured to supply the cooling water after flowing in the motor water jacket to the transmission mechanism water jacket, and a second distribution passage configured to supply the cooling water after flowing in the motor water jacket to the inverter water jacket. BRIEF DESCRIPTION OF DRAWINGS

[0004] Fig. 1 is an explanatory diagram illustrating a marine propulsion device according to an example of the present invention as viewed from the left. Fig. 2 is an explanatory diagram illustrating an upper part of the marine propulsion device according to the example of the present invention as viewed from the right. Fig. 3 is an explanatory diagram illustrating the upper part of the marine propulsion device according to the example of the present invention as viewed from behind. Fig. 4 is a cross-sectional view illustrating the marine propulsion device cut along a line A-A in Fig. 3 as viewed from the left. Fig. 5 is an explanatory diagram illustrating a motor, an upper case, a middle case, a lower case, and an inverter separated from each other in the marine propulsion device according to the example of the present invention. Fig. 6 is a cross-sectional view illustrating the marine propulsion device cut along a line D-D in Fig. 4 as viewed from above. Fig. 7 is a block diagram illustrating a cooling device in the marine propulsion device according to the example of the present invention. Fig. 8 is an enlarged cross-sectional view of a water pump, a supply passage, a motor water jacket, a distribution portion, and the like in the marine propulsion device in Fig. 4. Fig. 9 is an explanatory diagram illustrating an enlarged view of the distribution portion, a first distribution passage, a second distribution passage, a speed reducer water jacket, and the like in the marine propulsion device in Fig. 2. Fig. 10A is a cross-sectional view illustrating the second distribution passage, an inverter water jacket, and the like cut along a line B-B in Fig. 3 as viewed from the right, and Fig. 10B is a cross-sectional view illustrating the inverter water jacket, a water temperature control passage, a discharge passage, and the like cut along a line C-C in Fig. 3 as viewed from the left. DESCRIPTION OF EMBODIMENTS

[0005] The motor, the transmission mechanism, and the inverter generate heat during operation. To improve durability or performance of the devices, it is important to cool the

[0006] devices. To increase cooling efficiency, it is better to use water cooling rather than air cooling as a cooling method of the devices. Therefore, it is desirable that the marine propulsion device includes a water-cooled cooling device that cools the motor, the transmission mechanism, and the inverter.

[0007] In designing such a cooling device, it is desirable to appropriately cool each of the motor, the transmission mechanism, and the inverter while preventing insufficient or excessive cooling. To achieve such object, it is necessary to determine paths for supplying cooling water to the motor, the transmission mechanism, and the inverter and amounts of cooling water to be supplied to the motor, the transmission mechanism, and the inverter depending on the amount of generated heat or the required cooling power of each of the motor, the transmission mechanism, and the inverter. However, it is not easy to determine the supply paths and the supply amounts of cooling water as such.

[0008] The present invention is made considering, for example, the problems described above, and an object of the present invention is to provide a marine propulsion device in which each of a motor, a transmission mechanism, and an inverter can be appropriately cooled by a water-cooled cooling device.

[0009] A marine propulsion device according to an embodiment of the present invention includes a motor, a drive shaft, a first transmission mechanism that transmits rotation of the motor to the drive shaft, a propeller shaft provided with a propeller, a second transmission mechanism that transmits rotation of the drive shaft to the propeller shaft, an inverter that controls driving of the motor, and a cooling device.

[0010] The cooling device includes a motor water jacket that cools the motor, a transmission mechanism water jacket that cools the first transmission mechanism, an inverter water jacket that cools the inverter, a supply passage that supplies cooling water to the motor water jacket, and a distribution mechanism that distributes and supplies the cooling water after flowing in the motor water jacket to each of the transmission mechanism water jacket and the inverter water jacket in parallel.

[0011] The distribution mechanism also includes a first distribution passage that supplies the cooling water after flowing in the motor water jacket to the transmission mechanism water jacket, and a second distribution passage that supplies the cooling water after flowing in the motor water jacket to the inverter water jacket.

[0012] In the cooling device of the marine propulsion device of the embodiment, cooling water is first supplied to the motor water jacket via the supply passage. The motor is cooled by the cooling water flowing in the motor water jacket. Next, the cooling water after flowing in the motor water jacket is distributed and supplied to the transmission mechanism water jacket and the inverter water jacket in parallel. Specifically, a part of the cooling water after flowing in the motor water jacket is supplied to the transmission mechanism water jacket via the first distribution passage, and a remaining part of the cooling water after flowing in the motor water jacket is supplied to the inverter water jacket via the second distribution passage. The first transmission mechanism is cooled by the cooling water flowing in the transmission mechanism water jacket. The inverter is cooled by the cooling water flowing in the inverter water jacket.

[0013] In the cooling device of the marine propulsion device of the embodiment, a path for supplying cooling water to each of the motor, the first transmission mechanism, and the inverter and an amount of cooling water supplied to each of the motor, the first transmission mechanism, and the inverter are set according to an amount of heat generated by each of the motor, the first transmission mechanism, and the inverter, cooling power required for cooling each of the motor, the first transmission mechanism, and the inverter, or the like. Therefore, according to the cooling device of the marine propulsion device of the embodiment, it is possible to appropriately cool each of the motor, the first transmission mechanism, and the inverter while preventing insufficient or excessive cooling.

[0014] Specifically, the amount of generated heat or the required cooling power of the motor is greater than either of the amount of generated heat or the required cooling power of the first transmission mechanism and the amount of generated heat or the required cooling power of the inverter. In the cooling device of the marine propulsion device of the embodiment, a cooling water supply path is set so that the cooling water is first supplied to the motor water jacket, and then the cooling water after flowing in the motor water jacket is distributed and supplied to the transmission mechanism water jacket and the inverter water jacket in parallel. In such supply path, among temperatures of cooling water supplied to the motor water jacket, the transmission mechanism water jacket, and the inverter water jacket, the temperature of the cooling water supplied to the motor water jacket is lowest. Therefore, cooling capacity for the motor by the motor water jacket is higher than either of cooling capacity for the first transmission mechanism by the transmission mechanism water jacket and cooling capacity for the inverter by the inverter water jacket. Therefore, the motor that generates the greatest amount of heat or requires the largest cooling power can be cooled by the motor water jacket having the highest cooling capacity, thereby preventing insufficient cooling of the motor. Meanwhile, the first transmission mechanism and the inverter that each generate small amount of heat or require less cooling power than the motor can be cooled by each of the transmission mechanism water jacket and the inverter water jacket having lower cooling capacity than the motor water jacket, thereby preventing excessive cooling of the first transmission mechanism and the inverter.

[0015] In the cooling device of the marine propulsion device of the embodiment, the cooling water is supplied to the motor water jacket and then the cooling water after flowing in the motor water jacket is distributed and supplied to the transmission mechanism water jacket and the inverter water jacket in parallel, so that a total amount of the cooling water supplied to the transmission mechanism water jacket and the inverter water jacket is equal to the amount of the cooling water supplied to the motor water jacket. That is, the amount of the cooling water supplied to the motor water jacket is greater than either of the amount of the cooling water supplied to the transmission mechanism water jacket and the amount of the cooling water supplied to the inverter water jacket. Therefore, cooling capacity for the motor by the motor water jacket is higher than either of cooling capacity for the first transmission mechanism by the transmission mechanism water jacket and cooling capacity for the inverter by the inverter water jacket. Accordingly, the motor is cooled by the motor water jacket having the highest cooling capacity, thereby preventing insufficient cooling of the motor, while the first transmission mechanism and the inverter are each cooled by the transmission mechanism water jacket and the inverter water jacket having lower cooling capacity than the motor water jacket, thereby preventing excessive cooling of the first transmission mechanism and the inverter.Example

[0016] A marine propulsion device according to an example of the present invention will be described with reference to the drawings. In the description of the example, directions of up (Ud), down (Dd), front (Fd), back (Bd), left (Ld), and right (Rd) follow arrows drawn at the lower left in Figs. 1 to 6 and 8 to 10B.Marine Propulsion Device

[0017] Fig. 1 illustrates a marine propulsion device 1 according to the example of the present invention as viewed from the left. Fig. 2 illustrates an upper part of the marine propulsion device 1 as viewed from the right. Fig. 3 illustrates the upper part of the marine propulsion device 1 as viewed from behind. A clamp bracket 41 and the like are omitted in Fig. 3. Fig. 4 illustrates a cross section of the marine propulsion device 1 cut along a line A-A in Fig. 3 as viewed from the left. Fig. 5 illustrates a motor 3, an upper case 25, a middle case 26, a lower case 27, and an inverter 35 separated from one another. Fig. 6 illustrates a cross section of the marine propulsion device 1 cut along a line D-D in Fig. 4 as viewed from above.

[0018] The marine propulsion device 1 is a device for propelling a boat. As illustrated in Fig. 1, the marine propulsion device 1 is an outboard motor, and is mounted on a transom 101 of the boat.

[0019] As illustrated in Fig. 4, the marine propulsion device 1 includes the motor 3 as a power source for rotating a propeller 20, a drive shaft 8 that transmits power of the motor 3 to the propeller 20, a speed reducer 9 that reduces rotation of an output shaft 4 of the motor 3 and transmits the rotation to the drive shaft 8, a propeller shaft 13, a rotation transmission mechanism 14 that transmits rotation of the drive shaft 8 to the propeller shaft 13, and the propeller 20 that converts the power of the motor 3 into thrust for the boat. The marine propulsion device 1 includes a shift device 31 that controls switching of a rotation direction of the propeller 20. The marine propulsion device 1 includes the inverter 35 that controls driving of the motor 3. The speed reducer 9 is a specific example of a "first transmission mechanism", and the rotation transmission mechanism 14 is a specific example of a "second transmission mechanism".

[0020] The motor 3 and the speed reducer 9 are disposed in an upper part of the marine propulsion device 1. When the marine propulsion device 1 is mounted on the boat, the motor 3 and the speed reducer 9 are positioned above the water surface. Meanwhile, the rotation transmission mechanism 14, the propeller shaft 13, and the propeller 20 are disposed in a lower part of the marine propulsion device 1. When the marine propulsion device 1 is mounted to the boat, the rotation transmission mechanism 14, the propeller shaft 13, and the propeller 20 are positioned below the water surface.

[0021] As illustrated in Fig. 4, the motor 3 includes the output shaft 4 as a shaft that outputs power, a rotor 5 provided on an outer periphery of the output shaft 4, a stator 6 provided on an outer periphery of the rotor 5, and a motor case 7 having a substantially cylindrical shape. The motor case 7 accommodates the output shaft 4 excluding one end, the rotor 5, and the stator 6. The motor 3 is disposed so that an extension direction of the output shaft 4 is a vertical direction. The motor 3 is disposed so that an end of the output shaft 4 that outputs power of the motor 3 faces upward.

[0022] As illustrated in Fig. 4, the speed reducer 9 is disposed above the motor 3. In detail, the speed reducer 9 is disposed so that a front part of the speed reducer 9 is positioned above a swivel bracket 43 and a rear part of the speed reducer 9 is positioned above the motor 3. When the marine propulsion device 1 is viewed from above, the speed reducer 9 is disposed so that the front part overlaps with the swivel bracket 43. The front part of the speed reducer 9 is positioned above a pilot shaft 42. The speed reducer 9 is positioned above an upper mount 47.

[0023] As illustrated in Figs. 4 and 6, the speed reducer 9 includes a drive sprocket 10 that inputs rotation of the output shaft 4 of the motor 3 to the speed reducer 9, a driven sprocket 11 that reduces the rotation input to the speed reducer 9 and outputs the rotation from the speed reducer 9 to the drive shaft 8, and a silent chain 12 linking the drive sprocket 10 and the driven sprocket 11. A gear ratio between the drive sprocket 10 and the driven sprocket 11 is greater than 1. The gear ratio is determined by dividing the number of teeth of the driven sprocket 11 by the number of teeth of the drive sprocket 10.

[0024] The drive sprocket 10 is positioned above the motor 3 and disposed coaxially with the output shaft 4 of the motor 3. A lower end of a boss of the drive sprocket 10 is coupled (for example, by spline coupling) to an upper end of the output shaft 4 of the motor 3 so that the drive sprocket 10 rotates integrally with the output shaft 4.

[0025] The driven sprocket 11 is disposed in front of the drive sprocket 10. The driven sprocket 11 is disposed above the drive shaft 8 and coaxially with the drive shaft 8. A part of the driven sprocket 11 is positioned above the swivel bracket 43. A lower end of a boss of the driven sprocket 11 is coupled (for example, by spline coupling) to an upper end of the drive shaft 8.

[0026] The speed reducer 9 is accommodated in the upper case 25. As can be viewed from Figs. 1 and 5, the upper case 25 is disposed above the motor 3 and attached to the motor case 7 using a fastening member such as a bolt. The upper case is a specific example of a "transmission mechanism case".

[0027] The drive shaft 8 extends in the vertical direction from the speed reducer 9 to the rotation transmission mechanism 14. The drive shaft 8 is disposed between the swivel bracket 43 and the motor 3 that are aligned in a front-rear direction. As described above, the upper end of the drive shaft 8 is coupled to the lower end of the boss of the driven sprocket 11 so that the drive shaft 8 rotates integrally with the driven sprocket 11.

[0028] As can be viewed from Figs. 1 and 5, in the marine propulsion device 1, the middle case 26 is provided below the motor 3, and the lower case 27 is provided below the middle case 26. The middle case 26 is attached to the motor case 7 using a fastening member such as a bolt, and the lower case 27 is attached to the middle case 26 using a fastening member such as a bolt. As illustrated in Fig. 4, the upper end of the drive shaft 8 is covered by the upper case 25. An upper part of the drive shaft 8 that is a part below the upper end thereof is positioned in front of the motor 3 and passes outside of the motor case 7. A vertical middle part of the drive shaft 8 passes inside of the middle case 26. A lower part of the drive shaft 8 passes inside of the lower case 27.

[0029] The rotation transmission mechanism 14 is accommodated in the lower case 27. The rotation transmission mechanism 14 includes a transmission gear 15, a forward gear 16, a reverse gear 17, a dog clutch 18, and a shift plunger 19. The transmission gear 15, the forward gear 16, and the reverse gear 17 are all bevel gears. A rotation axis of the transmission gear 15 extends in the vertical direction. The transmission gear 15 is coupled to a lower end of the drive shaft 8 and rotates integrally with the drive shaft 8. A rotation axis of each of the forward gear 16 and the reverse gear 17 extends in the front-rear direction. The forward gear 16 is disposed in front of the transmission gear 15, and the reverse gear 17 is disposed behind the transmission gear 15. The forward gear 16 and the reverse gear 17 each mesh with the transmission gear 15, and upon receiving rotation of the transmission gear 15, the forward gear 16 and the reverse gear 17 rotate in opposite directions to each other. A through hole is formed in each of a center of the forward gear 16 and a center of the reverse gear 17, and a front part of the propeller shaft 13 is inserted into the through holes. The forward gear 16 and the reverse gear 17 are not fixed to the propeller shaft 13 and are rotatable relative to the propeller shaft 13. The dog clutch 18 is disposed between the forward gear 16 and the reverse gear 17. The dog clutch 18 is attached to a front part of the propeller shaft 13 to not be rotatable relative to the propeller shaft 13 and to be movable in the front-rear direction relative to the propeller shaft 13. The shift plunger 19 is attached inside a front end of the propeller shaft 13 to be movable in the front-rear direction relative to the propeller shaft 13. A rear end of the shift plunger 19 is connected to the dog clutch 18 and a front end of the shift plunger 19 is positioned near a lower end of a shift rod 33 so that rotation of the shift rod 33 is transmitted to the shift plunger 19 via a cam mechanism. When the shift rod 33 rotates by driving a shift actuator 32, the rotation of the shift rod 33 is transmitted to the shift plunger 19 via the cam mechanism so that the shift plunger 19 moves forward or rearward, and accordingly, the dog clutch 18 moves forward or rearward. When the dog clutch 18 moves forward, the dog clutch 18 and the forward gear 16 engage with each other, thereby transmitting the rotation of the forward gear 16 to the propeller shaft 13. Meanwhile, when the dog clutch 18 moves rearward, the dog clutch 18 and the reverse gear 17 engage with each other, thereby transmitting the rotation of the reverse gear 17 to the propeller shaft 13.

[0030] The propeller shaft 13 extends in the front-rear direction. The front part of the propeller shaft 13 is positioned in the lower case 27 and extends into the rotation transmission mechanism 14. A rear part of the propeller shaft 13 is positioned outside of the lower case 27. The propeller 20 is fixed to the rear part of the propeller shaft 13 and rotates integrally with the propeller shaft 13.

[0031] The shift device 31 includes the shift actuator 32 and the shift rod 33. The shift actuator 32 is an actuator that controls movement of the dog clutch 18, and is, for example, a small motor. The shift actuator 32 is provided in a front right part of an upper part of the upper case 25. The shift rod 33 is a rod that transmits power of the shift actuator 32 to the shift plunger 19. The shift rod 33 extends in the vertical direction from the shift actuator 32 toward the front end of the shift plunger 19. An upper part of the shift rod 33 passes inside of the pilot shaft 42 formed in a cylindrical shape, and a lower part of the shift rod 33 passes inside of the lower case 27. An upper end of the shift rod 33 is connected to the shift actuator 32, and a lower end of the shift rod 33 is positioned near the front end of the shift plunger 19. The shift rod 33 rotates by driving the shift actuator 32. Rotational motion of the shift rod 33 is converted into linear motion in the front-rear direction of the shift plunger 19 by a cam mechanism provided between the lower end of the shift rod 33 and the front end of the shift plunger 19. As described above, by moving the shift plunger 19, the dog clutch 18 moves.

[0032] The inverter 35 includes an inverter body 36 including electric and electronic circuits that control driving of the motor 3, and an inverter case 37 that accommodates the inverter body 36. The inverter 35 is disposed above the speed reducer 9 and attached to the upper case 25 using a fastening member such as a bolt.

[0033] By controlling the inverter 35, the motor 3 is driven and the output shaft 4 of the motor 3 rotates. As the output shaft 4 of the motor 3 rotates, the drive sprocket 10 of the speed reducer 9 rotates and rotation of the drive sprocket 10 is transmitted to the driven sprocket 11 via the silent chain 12 so that the driven sprocket 11 rotates. Meanwhile, rotation of the output shaft 4 of the motor 3 is reduced. Rotation of the driven sprocket 11 is transmitted to the forward gear 16 and the reverse gear 17 via the drive shaft 8 and the transmission gear 15 in this order. When the dog clutch 18 is moved forward by controlling the shift actuator 32, rotation of the forward gear 16 is transmitted to the propeller shaft 13 so that the propeller shaft 13 and the propeller 20 are rotated forward. Forward rotation of the propeller 20 generates thrust that moves the boat forward. Meanwhile, when the dog clutch 18 is moved rearward by controlling the shift actuator 32, rotation of the reverse gear 17 is transmitted to the propeller shaft 13 so that the propeller shaft 13 and the propeller 20 are rotated reversely. Reverse rotation of the propeller 20 generates thrust that moves the boat rearward.

[0034] As illustrated in Fig. 1, the marine propulsion device 1 includes a pair of left and right clamp brackets 41 that secure the marine propulsion device 1 to the transom 101 of the boat, the pilot shaft 42 that serves as an axis for pivoting the marine propulsion device 1 in the left-right direction, the swivel bracket 43 that is connected to the clamp brackets 41 and supports the pilot shaft 42 to be pivotable, a pair of left and right upper mounts 47 that connect an upper end of the pilot shaft 42 to the marine propulsion device 1, and a pair of left and right lower mounts 49 that connect a lower end of the pilot shaft 42 to the marine propulsion device 1.

[0035] The pair of left and right clamp brackets 41 and the swivel bracket 43 are disposed in front of the upper part of the marine propulsion device 1. Although not illustrated in detail, the swivel bracket 43 is disposed between the pair of clamp brackets 41. The swivel bracket 43 is connected to each clamp bracket 41 via a tilt shaft 44.

[0036] The pilot shaft 42 extends in the vertical direction and is pivotably supported by the swivel bracket 43. Front parts of the pair of left and right upper mounts 47 are coupled to the upper end of the pilot shaft 42. Rear parts of the pair of upper mounts 47 are inserted into the upper case 25 and each attached to the upper case 25 in the upper case 25. Front parts of the pair of left and right lower mounts 49 are coupled to the lower end of the pilot shaft 42. Rear parts of the pair of lower mounts 49 are attached to the middle case 26.Cooling Device

[0037] The marine propulsion device 1 includes a cooling device 51 that cools the motor 3, the speed reducer 9, and the inverter 35. The cooling device 51 is a water-cooled cooling device that uses water (for example, seawater) outside the marine propulsion device 1 to cool the motor 3, the speed reducer 9, and the inverter 35.

[0038] Fig. 7 illustrates a configuration of the cooling device 51. Fig. 8 illustrates an enlarged view of a water pump 54, a supply passage 57, a motor water jacket 58, the distribution portion 61, and the like in the marine propulsion device 1 in Fig. 4. Fig. 9 illustrates an enlarged view of the distribution portion 61, a first distribution passage 63, a second distribution passage 64, a speed reducer water jacket 65, and the like in the marine propulsion device 1 in Fig. 2. Fig. 10A illustrates a cross section of the second distribution passage 64, an inverter water jacket 71, and the like cut along a line B-B in Fig. 3 as viewed from the right. Fig. 10B illustrates a cross section of the inverter water jacket 71, a water temperature control passage 75, a discharge passage 77, and the like cut along a line C-C in Fig. 3 as viewed from the left.

[0039] As illustrated in Fig. 7, the cooling device 51 includes an intake port 52, an intake passage 53, the water pump 54, the supply passage 57, the motor water jacket 58, a distribution mechanism 60, the speed reducer water jacket 65, a water inspection port 66, the inverter water jacket 71, a cooling water temperature control valve 76, the discharge passage 77, and a drain port 80. The distribution mechanism 60 includes the distribution portion 61, the first distribution passage 63, and the second distribution passage 64. The speed reducer water jacket 65 is a specific example of a "transmission mechanism water jacket", the water inspection port 66 is a specific example of a "first drain port", and the drain port 80 is a specific example of a "second drain port". The cooling water temperature control valve 76 is a specific example of a "valve".

[0040] The intake port 52 is a port for taking water from outside of the marine propulsion device 1 into the marine propulsion device 1 as cooling water. The intake port 52 is provided in the lower part of the marine propulsion device 1 positioned below the water surface. Specifically, as illustrated in Fig. 1, the intake port 52 is provided in a front part of the lower case 27 and below an anti-cavitation plate 29.

[0041] As illustrated in Fig. 4, the intake passage 53 is a passage that connects the intake port 52 to a suction port of the water pump 54. The intake passage 53 is formed by, for example, a hole formed in the lower case 27. The cooling water taken in from the intake port 52 flows in the intake passage 53 toward the suction port of the water pump 54.

[0042] The water pump 54 is a pump that sends cooling water taken into the marine propulsion device 1 from outside of the marine propulsion device 1 via the intake port 52 to the motor water jacket 58 and the like. The water pump 54 is, for example, a rotary variable displacement water pump. As illustrated in Fig. 8, the water pump 54 is disposed below the motor 3. The water pump 54 is disposed in a lower part of inside of the middle case 26. An impeller 55 of the water pump 54 is attached to the drive shaft 8 and rotates integrally with the drive shaft 8. A pump case 56 of the water pump 54 is attached to an upper surface of the lower case 27.

[0043] The supply passage 57 is a passage that connects a discharge port 56A of the water pump 54 to an inlet port 58A of the motor water jacket 58 and supplies the cooling water to the motor water jacket 58. The supply passage 57 is provided in the middle case 26. The supply passage 57 is configured of a tube 57A formed by, for example, a pipe or a hose, and a hole 57B formed in the middle case 26. The cooling water discharged from the discharge port 56A of the water pump 54 flows in the supply passage 57 toward the inlet port 58A of the motor water jacket 58.

[0044] The motor water jacket 58 is provided in the motor 3 as illustrated in Fig. 8. The motor water jacket 58 is configured of a flow path provided around the motor 3. Specifically, the motor case 7 of the motor 3 includes a case body 7A having a cylindrical shape that surrounds an entire outer periphery of the stator 6, a cover 7B that closes one axial side of the case body 7A and is provided with a hole in a center through which the output shaft 4 passes, and a cover 7C that closes the other axial side of the case body 7A. The motor water jacket 58 includes, for example, a flow path 58B formed in the cover 7C, a flow path 58C formed in an entire periphery wall of the case body 7A, and a flow path 58D formed in the cover 7B. The flow paths 58B, 58C, and 58D are holes through which cooling water can flow. The flow paths 58B and 58C communicate with each other, and the flow paths 58C and 58D communicate with each other. The motor 3 is cooled by the cooling water flowing in the motor water jacket 58, that is, the flow paths 58B, 58C, and 58D.

[0045] The inlet port 58A of the motor water jacket 58 is provided at a front part of a lower part of the motor 3. The inlet port 58A is formed in a front part of the cover 7C. The inlet port 58A opens downward. The inlet port 58A is connected to the supply passage 57 and communicates with the flow path 58B. The cooling water flows from the supply passage 57 through the inlet port 58A into the flow path 58B.

[0046] An outlet port 58E of the motor water jacket 58 is provided at an upper part of a rear part of an outer circumferential surface of the motor 3. The outlet port 58E is formed in an upper part of a rear part of an outer circumferential surface of the case body 7A and opens rearward. The outlet port 58E communicates with the flow path 58C. The cooling water flowed in the flow paths 58B, 58C, and 58D flows out of the motor water jacket 58 from the outlet port 58E.

[0047] The distribution mechanism 60 is a mechanism that distributes and supplies the cooling water after flowing in the motor water jacket 58 to the speed reducer water jacket 65 and the inverter water jacket 71 in parallel. As illustrated in Fig. 9, the distribution mechanism 60 includes the distribution portion 61, the first distribution passage 63, and the second distribution passage 64.

[0048] The distribution portion 61 is a portion that distributes and supplies the cooling water after flowing in the motor water jacket 58 to the first distribution passage 63 and the second distribution passage 64. As illustrated in Figs. 8 and 9, the distribution portion 61 is formed in a capped cylindrical shape, and a distribution chamber 62 is formed in the distribution portion 61. Three holes 61A, 61B, and 61C that communicate with inside of the distribution chamber 62 is formed in the distribution portion 61. The hole 61A is formed on a front surface of the distribution portion 61 and opens forward, and the outlet port 58E of the motor water jacket 58 is connected to the hole 61A. The hole 61B is formed on an upper surface of the distribution portion 61 and opens upward, and one end of the first distribution passage 63 is connected to the hole 61B. The hole 61C is formed on a right surface of the distribution portion 61 and opens to the right, and one end of the second distribution passage 64 is connected to the hole 61C. The outlet port 58E of the motor water jacket 58, the first distribution passage 63, and the second distribution passage 64 each communicate with inside of the distribution chamber 62. The distribution portion 61 is disposed at the upper part of the rear part of the outer circumferential surface of the case body 7A of the motor case 7, and is attached to the case body 7A using a fastening member such as a bolt.

[0049] As illustrated in Fig. 9, the first distribution passage 63 is a passage that connects the distribution chamber 62 to an inlet port 65A of the speed reducer water jacket 65 and supplies the cooling water after flowing in the motor water jacket 58 to the speed reducer water jacket 65. The first distribution passage 63 is disposed in an area provided from a rear side to a right side of the upper part of the marine propulsion device 1. The first distribution passage 63 is configured of, for example, a tube 63A formed by a pipe or a hose, a joint 63B that connects one end of the tube 63A to the distribution chamber 62, and a joint 63C that connects the other end of the tube 63A to the inlet port 65A of the speed reducer water jacket 65. The first distribution passage 63 extends from the distribution portion 61, passes outside of the motor 3 and outside of the upper case 25, and reaches the inlet port 65A of the speed reducer water jacket 65. Specifically, the first distribution passage 63 extends upward from the upper surface of the distribution portion 61, then turns to the right, and then extends to the right, as illustrated in Fig. 3, and then turns forward, then extends forward, then turns upward, and then extends upward, as illustrated in Fig. 9, to reach the inlet port 65A of the speed reducer water jacket 65.

[0050] As illustrated in Figs. 2, 3, 9, and 10A, the second distribution passage 64 is a passage that connects the distribution chamber 62 to an inlet port 71A of the inverter water jacket 71 and supplies the cooling water after flowing in the motor water jacket 58 to the inverter water jacket 71. The second distribution passage 64 is disposed on a right rear side of the upper part of the marine propulsion device 1. The second distribution passage 64 is configured of, for example, a tube 64A formed by a pipe or a hose, a joint 64B that connects one end of the tube 64A to the distribution chamber 62, a connecting portion 64C having a tubular shape and integrally formed in a right rear part of the upper case 25, and a joint 64D that connects the other end of the tube 64A to one end of the connecting portion 64C. The inlet port 71A of the inverter water jacket 71 is connected to the other end of the connecting portion 64C. The second distribution passage 64 extends from the distribution portion 61, passes outside of the motor 3, and reaches the inlet port 71A of the inverter water jacket 71. Specifically, the second distribution passage 64 extends to the right from the right surface of the distribution portion 61, then bends roughly upward, and then extends roughly upward, as illustrated in Fig. 3, to reach the inlet port 71A of the inverter water jacket 71.

[0051] As illustrated in Fig. 2, a cross-sectional area of the second distribution passage 64 is larger than a cross-sectional area of the first distribution passage 63. Specifically, each of inner diameters of the tube 64A, the connecting portion 64C, and the joints 64B and 64D that configure the second distribution passage 64 are larger than each of inner diameters of the tube 63A and the joints 63B and 63C that configure the first distribution passage 63. A diameter of the hole 61C of the distribution portion 61 is larger than a diameter of the hole 61B of the distribution portion 61. A diameter of the inlet port 71A of the inverter water jacket 71 is larger than a diameter of the inlet port 65A of the speed reducer water jacket 65.

[0052] The cooling water flowed out from the outlet port 58E of the motor water jacket 58 flows into the distribution chamber 62. A part of the cooling water flowed into the distribution chamber 62 flows into the first distribution passage 63, flows in the first distribution passage 63, and flows into the inlet port 65A of the speed reducer water jacket 65. A remaining part of the cooling water flowed into the distribution chamber 62 flows into the second distribution passage 64, flows in the second distribution passage 64, and flows into the inlet port 71A of the inverter water jacket 71. Since the cross-sectional area of the second distribution passage 64 is larger than the cross-sectional area of the first distribution passage 63, an amount of cooling water flowing from the distribution chamber 62 in the second distribution passage 64 into the inlet port 71A of the inverter water jacket 71 is greater than an amount of cooling water flowing from the distribution chamber 62 in the first distribution passage 63 into the inlet port 65A of the speed reducer water jacket 65.

[0053] As illustrated in Fig. 9, the speed reducer water jacket 65 is provided in the upper case 25 that accommodates the speed reducer 9. The speed reducer water jacket 65 is configured of a flow path (for example, a hole) for cooling water formed in, for example, the upper case 25. The speed reducer water jacket 65 cools oil stored in the upper case 25 by flowing the cooling water supplied via the first distribution passage 63 in the flow path of the speed reducer water jacket 65. The oil is sprayed onto the speed reducer 9, thereby cooling the speed reducer 9. Specifically, as illustrated in Figs. 4 and 6, an oil jet device 82 is provided below the speed reducer 9 in the upper case 25. Although detailed illustration is omitted, the oil jet device 82 includes, for example, a small pump driven by rotation of the drive sprocket 10, an oil spraying tube that sprays oil toward the speed reducer 9 by driving the pump, an oil storage portion that stores the oil to be sprayed from the oil spraying tube onto the speed reducer 9, an oil supply passage that supplies the oil stored in the oil storage portion to the oil spraying tube, and an oil return passage that returns the oil after being sprayed from the oil spraying tube onto the speed reducer 9 to the oil storage portion. A cooling water flow path that configures the speed reducer water jacket 65 is disposed in a position close to the oil storage portion so that heat exchange occurs between the oil stored in the oil storage portion and the cooling water flowing in the cooling water flow path that configures the speed reducer water jacket 65.

[0054] As illustrated in Fig. 9, the inlet port 65A of the speed reducer water jacket 65 is disposed on a right surface of the upper case 25. As illustrated in Fig. 3, the inlet port 65A opens downward. The other end of the first distribution passage 63 is connected to the inlet port 65A. The inlet port 65A communicates with inside of the speed reducer water jacket 65, that is, the flow path that configures the speed reducer water jacket 65. The cooling water flows from the first distribution passage 63 through the inlet port 65A into the speed reducer water jacket 65.

[0055] The speed reducer water jacket 65 includes the water inspection port 66. The water inspection port 66 is disposed on the right surface of the upper case 25. The water inspection port 66 has a function for a user to confirm that the cooling device 51 is operating normally, and a function of discharging the cooling water supplied to the speed reducer water jacket 65 to outside of the marine propulsion device 1. The water inspection port 66 opens to the right. The water inspection port 66 communicates with inside of the speed reducer water jacket 65. The cooling water after flowing in the speed reducer water jacket 65 is discharged to outside of the marine propulsion device 1 from the water inspection port 66. The water inspection port 66 is a specific example of a "first drain port".

[0056] As illustrated in Fig. 10A, the inverter water jacket 71 is provided in a lower part of the inverter 35. Specifically, a lower protrusion portion 72 that protrudes downward from a lower surface of the inverter case 37 is formed in a rear part of the inverter case 37. The inverter water jacket 71 includes a flow path 71B provided in the lower protrusion portion 72. The flow path 71B is a hole through which cooling water can flow. The flow path 71B extends from a right end to a left end of the inverter 35. Specifically, the flow path 71B extends from a right end to a left end of the lower protrusion portion 72. The inverter 35 is cooled by the cooling water flowing in the inverter water jacket 71, that is, the flow path 71B.

[0057] The inlet port 71A of the inverter water jacket 71 is provided in a lower part of a right end of the lower protrusion portion 72. The inlet port 71A opens downward. The other end of the second distribution passage 64 is connected to the inlet port 71A, and the inlet port 71A communicates with the flow path 71B. The cooling water flows from the second distribution passage 64 through the inlet port 71A into the flow path 71B.

[0058] As illustrated in Fig. 10B, an outlet port 71C of the inverter water jacket 71 is provided in a lower part of a left end of the lower protrusion portion 72. The outlet port 71C opens downward. The outlet port 71C communicates with inside of the flow path 71B via the water temperature control passage 75 described below. The cooling water flowed in the flow path 71B passes inside of the water temperature control passage 75 and flows out of the inverter water jacket 71 from the outlet port 71C.

[0059] The water temperature control passage 75 is provided in a left rear part of the inverter 35. The water temperature control passage 75 is disposed between the flow path 71B of the inverter water jacket 71 and the outlet port 71C of the inverter water jacket 71. The water temperature control passage 75 is configured of, for example, holes formed in a left rear part of the inverter case 37 and in an upper protrusion portion 73 that protrudes upward from a left rear part of an upper surface of the inverter case 37. One end of the water temperature control passage 75 communicates with the flow path 71B, and the other end of the water temperature control passage 75 communicates with the outlet port 71C. The cooling water flowed in the flow path 71B passes inside of the water temperature control passage 75 and reaches the outlet port 71C.

[0060] The cooling water temperature control valve 76 is provided midway of the water temperature control passage 75. The cooling water temperature control valve 76 is a valve that changes an amount of the cooling water flowing out from the inverter water jacket 71 according to a temperature of the cooling water flowed in the inverter water jacket 71. Specifically, the cooling water temperature control valve 76 detects the temperature of the cooling water flowing in the water temperature control passage 75 and changes a valve opening degree based on the detected temperature, thereby changing the amount of the cooling water flowing out from the outlet port 71C of the inverter water jacket 71. The cooling water temperature control valve 76 may be, for example, a thermostat. The cooling water temperature control valve 76 is described in detail below.

[0061] The discharge passage 77 is a passage that connects the outlet port 71C of the inverter water jacket 71 to the drain port 80 and for flowing the cooling water flowed out from the outlet port 71C of the inverter water jacket 71 toward the drain port 80. As illustrated in Figs. 1, 3, and 10B, the discharge passage 77 is disposed on a left rear side of the upper part of the marine propulsion device 1. The discharge passage 77 is configured of, for example, a connecting portion 77A having a tubular shape, integrally formed in a left rear part of the upper case 25, and having one end connected to the outlet port 71C of the inverter water jacket 71, a tube 77B formed by a pipe or a hose, a joint 77C that connects one end of the tube 77B to the other end of the connecting portion 77A, and a joint 77D that connects the other end of the tube 77B to a communication hole 78 provided on the middle case 26. The communication hole 78 is provided on a left wall of the middle case 26 and communicates with inside of a rear part of the middle case 26. The discharge passage 77 extends downward from the outlet port 71C of the inverter water jacket 71, passes outside of the motor 3, and reaches the communication hole 78. The cooling water flowed out from the outlet port 71C of the inverter water jacket 71 flows in the discharge passage 77, then passes inside of the communication hole 78, and flows into inside of the rear part of the middle case 26.

[0062] The drain port 80 is provided in the lower part of the marine propulsion device 1. For example, the drain port 80 is provided inside of a hub of the propeller 20 as illustrated in Fig. 4. In the marine propulsion device 1, a space 79 is provided from inside of the rear part of the middle case 26 to inside of a rear part of the lower case 27. The cooling water flowed into inside of the rear part of the middle case 26 from the communication hole 78 flows in the space 79 and is then discharged from the marine propulsion device 1 from the drain port 80.

[0063] An operation of the cooling device 51 is as follows. By driving the motor 3, the drive shaft 8 rotates and the water pump 54 is driven. By driving the water pump 54, water outside of the marine propulsion device 1 is taken in from the water intake port 52 as cooling water, transported to the water pump 54 via the water intake passage 53, and discharged from the discharge port 56A of the water pump 54. The cooling water discharged from the discharge port 56A of the water pump 54 is supplied to the motor water jacket 58 via the supply passage 57. The cooling water supplied to the motor water jacket 58 flows in the motor water jacket 58, thereby cooling the motor 3. The cooling water flowed in the motor water jacket 58 flows into the distribution chamber 62. The cooling water flowed into the distribution chamber 62 is distributed and supplied to the speed reducer water jacket 65 and the inverter water jacket 71 via the first distribution passage 63 and the second distribution passage 64. The cooling water supplied to the speed reducer water jacket 65 via the first distribution passage 63 flows in the speed reducer water jacket 65, thereby cooling the oil stored in the oil storage portion of the oil jet device 82, and the oil is sprayed onto the speed reducer 9 by the oil jet device 82, thereby cooling the speed reducer 9. The cooling water flowed in the speed reducer water jacket 65 is discharged to outside of the marine propulsion device 1 from the water inspection port 66. The cooling water supplied to the inverter water jacket 71 via the second distribution passage 64 flows in the inverter water jacket 71, thereby cooling the inverter 35. The cooling water flowed in the inverter water jacket 71 is transported via the discharge passage 77 into the space 79 provided inside of the rear part of the middle case 26 and inside of the rear part of the lower case 27, and is then discharged to outside of the marine propulsion device 1 from the drain port 80.

[0064] The cooling water flowed in the flow path 71B of the inverter water jacket 71 passes the water temperature control passage 75 and flows out from the outlet port 71C of the inverter water jacket 71 into the discharge passage 77. The cooling water temperature control valve 76 changes the amount of the cooling water flowing out from the outlet port 71C of the inverter water jacket 71 into the discharge passage 77 according to the temperature of the cooling water flowing in the water temperature control passage 75. Specifically, the cooling water temperature control valve 76 increases the amount of the cooling water flowing out from the outlet port 71C of the inverter water jacket 71 as the temperature of the cooling water flowing in the water temperature control passage 75 is higher.

[0065] According to the cooling water temperature control valve 76 operating as such, it is possible to perform control to adjust the temperature of the cooling water flowing in the motor water jacket 58 and the inverter water jacket 71 according to a total amount of heat generated by the motor 3 and the inverter 35. Specifically, when the amount of heat generated by the motor 3 and the inverter 35 increases and the temperature of the cooling water flowing in the motor water jacket 58 and the inverter water jacket 71 rises, the temperature of the cooling water can be lowered.

[0066] Here, it will be described that, by changing the amount of the cooling water flowing out from the outlet port 71C of the inverter water jacket 71 into the discharge passage 77 according to the temperature of the cooling water flowing in the water temperature control passage 75, it is possible to perform control to adjust the temperature of the cooling water flowing in the motor water jacket 58 and the inverter water jacket 71 according to the total amount of heat generated by the motor 3 and the inverter 35.

[0067] The cooling water flowing in the water temperature control passage 75 is the cooling water flowed in the motor water jacket 58 and the flow path 71B of the inverter water jacket 71. Therefore, the temperature of the cooling water flowing in the water temperature control passage 75 rises upon receiving heat from the motor 3 and the inverter 35. Therefore, the temperature of the cooling water flowing in the water temperature control passage 75 can be regarded to represent the total amount of heat generated by the motor 3 and the inverter 35.

[0068] By changing the amount of the cooling water flowing out from the outlet port 71C of the inverter water jacket 71 into the discharge passage 77, the amount of the cooling water flowing in the motor water jacket 58 and the inverter water jacket 71 can be changed. By changing the amount of the cooling water flowing in each of the motor water jacket 58 and the inverter water jacket 71, the temperature of the cooling water flowing in each of the motor water jacket 58 and the inverter water jacket 71 can be changed. Specifically, by increasing the amount of the cooling water flowing in each of the motor water jacket 58 and the inverter water jacket 71, the temperature of the cooling water flowing in each of the motor water jacket 58 and the inverter water jacket 71 falls.

[0069] Therefore, by changing the amount of the cooling water flowing out from the outlet port 71C of the inverter water jacket 71 into the discharge passage 77 according to the temperature of the cooling water flowing in the water temperature control passage 75, it is possible to perform control to adjust the temperature of the cooling water flowing in the motor water jacket 58 and the inverter water jacket 71 according to the total amount of heat generated by the motor 3 and the inverter 35.

[0070] As described above, in the marine propulsion device 1 of the example, the cooling device 51 includes the supply passage 57 that supplies cooling water to the motor water jacket 58, and the distribution mechanism 60 that distributes and supplies the cooling water after flowing in the motor water jacket 58 to each of the speed reducer water jacket 65 and the inverter water jacket 71 in parallel, and the distribution mechanism 60 includes the first distribution passage 63 that supplies the cooling water after flowing in the motor water jacket 58 to the speed reducer water jacket 65, and the second distribution passage 64 that supplies the cooling water after flowing in the motor water jacket 58 to the inverter water jacket 71. By such configuration, the motor 3, the speed reducer 9, and the inverter 35 can each be appropriately cooled while preventing insufficient or excessive cooling, according to the amount of generated heat or the required cooling power of each of the motor 3, the speed reducer 9, and the inverter 35.

[0071] Specifically, the amount of generated heat or the required cooling power of the motor 3 is greater than either of the amount of generated heat or the required cooling power of the speed reducer 9 and the amount of generated heat or the required cooling power of the inverter 35. In the cooling device 51 of the marine propulsion device 1 of the example, the cooling water is first supplied to the motor water jacket 58, and then the cooling water after flowing in the motor water jacket 58 is distributed and supplied to the speed reducer water jacket 65 and the inverter water jacket 71 in parallel. Therefore, among the temperatures of the cooling water supplied to the motor water jacket 58, the speed reducer water jacket 65, and the inverter water jacket 71, the temperature of the cooling water supplied to the motor water jacket 58 is lowest. Accordingly, cooling capacity for the motor 3 by the motor water jacket 58 is higher than either of cooling capacity for the speed reducer 9 by the speed reducer water jacket 65 and cooling capacity for the inverter 35 by the inverter water jacket 71. Thus, the motor 3 that generates the greatest amount of heat or requires the largest cooling power can be cooled by the motor water jacket 58 having the highest cooling capacity, thereby preventing insufficient cooling of the motor 3. Meanwhile, the speed reducer 9 and the inverter 35 that each generate less heat or require less cooling power than the motor 3 can be cooled by each of the speed reducer water jacket 65 and the inverter water jacket 71 having lower cooling capacity than the motor water jacket 58, thereby preventing excessive cooling of the speed reducer 9 and the inverter 35.

[0072] In the cooling device 51 of the marine propulsion device 1 of the example, the cooling water is supplied to the motor water jacket 58, and the cooling water after flowing in the motor water jacket 58 is distributed and supplied to the speed reducer water jacket 65 and the inverter water jacket 71 in parallel, so that the total amount of the cooling water supplied to the speed reducer water jacket 65 and the inverter water jacket 71 is equal to the amount of the cooling water supplied to the motor water jacket 58. That is, the amount of the cooling water supplied to the motor water jacket 58 is greater than either of the amount of the cooling water supplied to the speed reducer water jacket 65 and the amount of the cooling water supplied to the inverter water jacket 71. Therefore, the cooling capacity for the motor 3 by the motor water jacket 58 is higher than either of the cooling capacity for the speed reducer 9 by the speed reducer water jacket 65 and the cooling capacity for the inverter 35 by the inverter water jacket 71. Accordingly, the motor 3 is cooled by the motor water jacket 58 having the highest cooling capacity, thereby preventing insufficient cooling of the motor 3, while the speed reducer 9 and the inverter 35 are each cooled by the speed reducer water jacket 65 and the inverter water jacket 71 having lower cooling capacity than the motor water jacket 58, thereby preventing excessive cooling of the speed reducer 9 and the inverter 35.

[0073] In the cooling device 51 of the marine propulsion device 1 of the example, the cross-sectional area of the second distribution passage 64 is larger than the cross-sectional area of the first distribution passage 63. By such configuration, the speed reducer 9 and the inverter 35 can each be appropriately cooled while preventing insufficient or excessive cooling, according to the amount of generated heat or the required cooling power of each of the speed reducer 9 and the inverter 35. Specifically, the amount of generated heat or the required cooling power of the inverter 35 is greater than the amount of generated heat or the required cooling power of the speed reducer 9. In the cooling device 51 of the marine propulsion device 1 of the example, the cross-sectional area of the second distribution passage 64 is larger than the cross-sectional area of the first distribution passage 63, so that the amount of the cooling water supplied to the inverter water jacket 71 is greater than the amount of the cooling water supplied to the speed reducer water jacket 65. Therefore, the cooling capacity for the inverter 35 by the inverter water jacket 71 is higher than the cooling capacity for the speed reducer 9 by the speed reducer water jacket 65. Accordingly, the inverter 35 that generates more heat or requires larger cooling power than the speed reducer 9 can be cooled by the inverter water jacket 71 having high cooling capacity, thereby preventing insufficient cooling of the inverter 35. Meanwhile, the speed reducer 9 that generates less heat or requires less cooling power than the inverter 35 can be cooled by the speed reducer water jacket 65 having lower cooling capacity than the inverter water jacket 71, thereby preventing excessive cooling of the speed reducer 9.

[0074] In the marine propulsion device 1 of the example, the speed reducer 9 is disposed above the motor 3, the distribution portion 61 of the distribution mechanism 60 is provided on the side surface of the motor case 7 of the motor 3, the inlet port 65A of the speed reducer water jacket 65 is provided on the right surface of the upper case 25 accommodating the speed reducer 9, and the first distribution passage 63 extends from the distribution portion 61, passes outside of the motor 3 and outside of the upper case 25, and reaches the inlet port 65A of the speed reducer water jacket 65. By such configuration, the first distribution passage 63 can be formed by a pipe or a hose attached to the motor 3 and the upper case 25 from outside. Therefore, compared to the first distribution passage 63 being formed by drilling holes in the motor 3 and the upper case 25, the first distribution passage 63 can be easily provided in the marine propulsion device 1.

[0075] In the marine propulsion device 1 of the example, the speed reducer 9 is disposed above the motor 3, and the speed reducer water jacket 65 is provided with the water inspection port 66 that discharges the cooling water supplied to the speed reducer water jacket 65 to outside of the marine propulsion device 1, in which the water inspection port 66 is disposed on the right surface of the upper case 25 accommodating the speed reducer 9. By such configuration, the cooling water after flowing in the speed reducer water jacket 65 can be easily discharged to outside of the marine propulsion device 1 and be easily inspected.

[0076] In the marine propulsion device 1 of the example, the inverter 35 is disposed above the motor 3, the distribution portion 61 of the distribution mechanism 60 is provided in an upper part of the side surface of the motor case 7 of the motor 3, and the inverter water jacket 71 is provided in the lower part of the inverter 35. By such configuration, the second distribution passage 64 that connects the distribution portion 61 to the inverter water jacket 71 can be shortened, and pressure loss caused by the cooling water flowing in the second distribution passage 64 can be reduced.

[0077] In the marine propulsion device 1 of the example, the inverter 35 is disposed above the motor 3, the distribution portion 61 of the distribution mechanism 60 is provided on the side surface of the motor case 7 of the motor 3, the inlet port 71A of the inverter water jacket 71 is provided in the lower part of the inverter 35, and the second distribution passage 64 extends upward from the distribution portion 61 and reaches the inlet port 71A of the inverter water jacket 71. By such configuration, the second distribution passage 64 can be shortened.

[0078] In the marine propulsion device 1 of the example, the inverter 35 is disposed above the motor 3, the cooling device 51 includes the drain port 80 provided in the lower part of the marine propulsion device 1 and the discharge passage 77 that connects the outlet port 71C of the inverter water jacket 71 to the drain port 80, the outlet port 71C of the inverter water jacket 71 is provided in the lower part of the inverter 35, and the discharge passage 77 extends downward from the outlet port 71C of the inverter water jacket 71. By such configuration, the discharge passage 77 that connects the inverter water jacket 71 positioned in the upper part of the marine propulsion device 1 to the drain port 80 positioned in the lower part of the marine propulsion device 1 can be shortened.

[0079] The cooling device 51 of the marine propulsion device 1 of the example includes the cooling water temperature control valve 76 that changes the amount of the cooling water flowing out from the inverter water jacket 71 according to the temperature of the cooling water flowed in the inverter water jacket 71. By such configuration, the temperature of the cooling water flowing in the motor water jacket 58 and the inverter water jacket 71 can be controlled by a single valve according to the total amount of heat generated by the motor 3 and the inverter 35, thereby simplifying such configuration for performing cooling water temperature control.

[0080] In the above-described example, the distribution portion 61 is disposed in the rear part of the outer circumferential surface of the motor 3, but the arrangement of the distributing portion 61 is not limited thereto. For example, the distribution portion 61 may be disposed on a left part or a right part of the outer circumferential surface of the motor 3. In the above-described example, the inlet port 65A of the speed reducer water jacket 65 is disposed on the right surface of the upper case 25, but the arrangement of the inlet port 65A of the speed reducer water jacket 65 is not limited thereto. For example, the inlet port 65A of the speed reducer water jacket 65 may be disposed on a left surface or a rear surface of the upper case 25. The water inspection port 66 may be disposed on the left surface or the rear surface of the upper case 25 instead of the right surface of the upper case 25.

[0081] In the above-described example, the silent chain 12 is used as the chain of the speed reducer 9, but other types of chains such as a roller chain may be used as the chain of the speed reducer 9. The speed reducer 9 may include a plurality of pulleys and a belt linking the pulleys. The speed reducer 9 may mesh with a plurality of gears.

[0082] The present invention can also be applied to other types of marine propulsion devices that are not outboard motors, such as inboard / outboard motors.

[0083] According to the present invention, each of the motor, the transmission mechanism, and the inverter provided in the marine propulsion device can be appropriately cooled by the water-cooled cooling device.

[0084] The present invention can be modified as appropriate without departing from the spirit or the concept of the invention as can be read from the claims and the entire specification, and marine propulsion devices incorporating such modifications are also included in the technical concept of the present invention.

Claims

1. A marine propulsion device (1) comprising: a motor (3); a drive shaft (8); a first transmission mechanism (9) configured to transmit a rotation of the motor to the drive shaft; a propeller shaft (13) provided with a propeller (20); a second transmission mechanism (14) configured to transmit a rotation of the drive shaft to the propeller shaft; an inverter (35) configured to control driving of the motor; and a cooling device (51), wherein the cooling device includes a motor water jacket (58) configured to cool the motor, a transmission mechanism water jacket (65) configured to cool the first transmission mechanism, an inverter water jacket (71) configured to cool the inverter, a supply passage (57) configured to supply a cooling water to the motor water jacket, and a distribution mechanism (60) configured to distribute and supply the cooling water after flowing in the motor water jacket to the transmission mechanism water jacket and the inverter water jacket in parallel, and the distribution mechanism includes a first distribution passage (63) configured to supply the cooling water after flowing in the motor water jacket to the transmission mechanism water jacket, and a second distribution passage (64) configured to supply the cooling water after flowing in the motor water jacket to the inverter water jacket.

2. The marine propulsion device according to claim 1, wherein a cross-sectional area of the second distribution passage is larger than a cross-sectional area of the first distribution passage.

3. The marine propulsion device according to claim 1, wherein the first transmission mechanism is disposed above the motor, the distribution mechanism includes a distribution portion (61) connected to each of an outlet port (58E) of the motor water jacket, one end of the first distribution passage, and one end of the second distribution passage, the distribution portion is provided on a side surface of a motor case of the motor, an inlet port of the transmission mechanism water jacket is provided on a side surface of a transmission mechanism case accommodating the first transmission mechanism, and the first distribution passage extends from the distribution portion, passes outside of the motor and outside of the transmission mechanism case, and reaches the inlet port of the transmission mechanism water jacket.

4. The marine propulsion device according to claim 1, wherein the first transmission mechanism is disposed above the motor, the transmission mechanism water jacket is provided with a first drain port (66) configured to discharge the cooling water supplied to the transmission mechanism water jacket to outside of the marine propulsion device, and the first drain port is disposed on a side surface of a transmission mechanism case accommodating the first transmission mechanism.

5. The marine propulsion device according to claim 1, wherein the inverter is disposed above the motor, the distribution mechanism includes a distribution portion (61) connected to each of an outlet port (58E) of the motor water jacket, one end of the first distribution passage, and one end of the second distribution passage, the distribution portion is provided in an upper part of a side surface of a motor case of the motor, and the inverter water jacket is provided in a lower part of the inverter.

6. The marine propulsion device according to claim 1, wherein the inverter is disposed above the motor, the distribution mechanism includes a distribution portion (61) connected to each of an outlet port (58E) of the motor water jacket, one end of the first distribution passage, and one end of the second distribution passage, the distribution portion is provided on a side surface of a motor case of the motor, an inlet port (71A) of the inverter water jacket is provided in a lower part of the inverter, and the second distribution passage extends upward from the distribution portion and reaches the inlet port of the inverter water jacket.

7. The marine propulsion device according to claim 1, wherein the inverter is disposed above the motor, the cooling device includes a second drain port (80) provided in a lower part of the marine propulsion device and configured to discharge the cooling water after flowing in the inverter water jacket to outside of the marine propulsion device, and a discharge passage (77) connecting an outlet port (71C) of the inverter water jacket to the second drain port, the outlet port of the inverter water jacket is provided in a lower part of the inverter, and the discharge passage extends downward from the outlet port of the inverter water jacket.

8. The marine propulsion device according to claim 1, wherein the cooling device includes a valve (76) configured to change an amount of cooling water flowing out of the inverter water jacket according to a temperature of the cooling water flowed in the inverter water j acket.

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