Ship propulsion machine

Abstract

To provide a ship propulsion machine that reduces a possibility that movement of a ship will become difficult in an event that a motor that generates a propulsive force of the ship fails during navigation, while also preventing significant increase of the size of the ship propulsion machine.SOLUTION: A power unit 2 of an outboard engine includes a lower motor 21, an upper motor 41, and a power transmission device 61. The power transmission device 61 is configured to selectively transmit at least one of power from the lower motor 21 and power from the upper motor 41 to a drive shaft 4. The lower motor 21 and the upper motor 41 are arranged in an upper part of the outboard engine. Motor shafts 22, 42 of the respective motors and the drive shaft 4 extend in a vertical direction. The upper motor 41 is arranged above the lower motor 21. An upper part of the drive shaft 4 passes through the motor shaft 22 to be rotatable independently of the motor shaft 22 of the lower motor 21 and reaches a region between the lower motor 21 and the upper motor 41. The power transmission device 61 is arranged between the lower motor 21 and the upper motor 41.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a marine propulsion unit that uses a motor (electric motor) as a power source for generating the propulsion force of a ship.

Background Art

[0002] In an outboard motor, there is known a structure in which a motor is provided in a portion located below the water surface in a state of being attached to a hull, that is, in the lower part of the outboard motor, and a propeller is attached to the rear end of a shaft extending rearward from the motor. In this type of outboard motor, since the motor is arranged in the lower part of the outboard motor, when a large motor is adopted, the lower part of the outboard motor becomes large, and there is a possibility that the water resistance during navigation increases. Therefore, it is difficult to adopt a large motor in this type of outboard motor.

[0003] On the other hand, as described in Japanese Patent Application Laid-Open No. 2005-153727 (Patent Document 1), in an outboard motor, there is known a structure in which a motor is provided in a portion located above the water surface in a state of being attached to a hull, that is, in the upper part of the outboard motor. This type of outboard motor has a drive shaft that extends vertically between the motor and a propeller shaft provided in the lower part of the outboard motor, and is configured to transmit the output of the motor to the propeller shaft by this drive shaft. In this type of outboard motor, since the motor is provided in the upper part of the outboard motor, even when a large motor is adopted, it is possible to suppress the lower part of the outboard motor from becoming large. Therefore, it is easy to adopt a large motor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a marine propulsion device that uses a motor as a power source for generating the propulsion force of a ship, if the motor fails during navigation, it becomes difficult to move the ship.

[0006] In this regard, a method of providing two motors in the marine propulsion device and moving the ship with the other motor when one motor fails can be considered. For example, this method can be realized by providing a first motor, a second motor, and a power transmission mechanism in the marine propulsion device, and switching the output of the second motor to be transmitted to the propeller from the state where the output of the first motor is transmitted to the propeller by the power transmission mechanism.

[0007] However, when the first motor, the second motor, and the power transmission mechanism are provided in the marine propulsion device, there is a risk that the marine propulsion device will be significantly enlarged compared to a marine propulsion device provided with only one motor as a power source for generating the propulsion force of the ship. For example, when the first motor, the second motor, and the power transmission mechanism are provided at the lower part of the outboard motor, the lower part of the outboard motor becomes significantly larger, which may increase the water resistance during navigation. Also, even when the first motor, the second motor, and the power transmission mechanism are provided at the upper part of the outboard motor, the upper part of the outboard motor becomes significantly larger, which may increase the air resistance during navigation, reduce the stability of the attachment of the outboard motor to the hull, or deteriorate the appearance of the outboard motor.

[0008] The present invention has been made in view of problems such as those described above, and an object of the present invention is to provide a marine propulsion device that can prevent the marine propulsion device from being significantly enlarged and can reduce the possibility of difficulty in moving the ship when the motor for generating the propulsion force of the ship fails during navigation.

Means for Solving the Problems

[0009] In order to solve the above problems, the present invention provides a marine propulsion unit including a power unit that generates power, a propeller, and a drive shaft for transmitting the power generated by the power unit to the propeller. The power unit includes a first motor having a first motor shaft, a second motor having a second motor shaft, and a power transmission device that transmits either the first power output from the first motor shaft or the second power output from the second motor shaft to the drive shaft and switches the power transmitted to the drive shaft between the first power and the second power. The first motor and the second motor are arranged at the upper part of the marine propulsion unit. The first motor shaft, the second motor shaft, and the drive shaft each extend in the vertical direction. The second motor is arranged above the first motor. The upper part of the drive shaft passes through the first motor shaft independently rotatably and reaches between the first motor and the second motor, and the power transmission device is arranged between the first motor and the second motor.

Advantages of the Invention

[0010] According to the present invention, it is possible to prevent the marine propulsion unit from being significantly enlarged, and to reduce the possibility that the movement of the ship becomes difficult when the motor that generates the propulsion force of the ship fails during navigation.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

[0012] The marine propulsion unit according to the embodiment of the present invention includes a power unit that generates power, a propeller, and a drive shaft for transmitting the power generated by the power unit to the propeller. For example, the drive shaft is connected to a propeller shaft to which the propeller is fixed via a gear mechanism.

[0013] In the marine propulsion unit of the present embodiment, the power unit includes a first motor having a first motor shaft, a second motor having a second motor shaft, and a power transmission device. The power transmission device transmits either the first power output from the first motor shaft or the second power output from the second motor shaft to the drive shaft. Further, the power transmission device switches the power transmitted to the drive shaft between the first power and the second power.

[0014] In the ship propulsion machine of the present embodiment, the first motor and the second motor are arranged above the ship propulsion machine. Further, the first motor shaft, the second motor shaft, and the drive shaft each extend in the vertical direction. Further, the second motor is arranged above the first motor. Further, the upper part of the drive shaft passes through the first motor shaft and reaches between the first motor and the second motor. Further, the drive shaft is rotatable independently of the first motor shaft. For example, the first motor shaft is formed in a cylindrical shape having an inner diameter larger than the outer diameter of the drive shaft, and the upper part of the drive shaft is inserted on the inner peripheral side of the first motor shaft in a state of being separated from the inner peripheral surface of the first motor shaft. Further, the power transmission device is arranged between the first motor and the second motor.

[0015] According to the ship propulsion machine of the present embodiment, it is possible to reduce the possibility that the movement of the ship becomes difficult when the motor that generates the propulsion force of the ship fails during navigation. Specifically, since the power transmitted to the drive shaft can be switched between the first power by the first motor and the second power by the second motor, when the first motor fails, the ship can be moved by the second motor, and when the second motor fails, the ship can be moved by the first motor.

[0016] Further, according to the ship propulsion machine of the present embodiment, it is possible to prevent the ship propulsion machine from being significantly enlarged due to the provision of the first motor, the second motor, and the power transmission device in the ship propulsion machine. Specifically, the first motor and the second motor are arranged side by side in the vertical direction such that their respective motor shafts extend in the vertical direction, and by arranging the power transmission device between the first motor and the second motor, the power transmission device can be formed compactly, and the degree of enlargement of the ship propulsion machine compared to a ship propulsion machine having only one motor can be reduced.

[0017] Specifically explaining the point that the power transmission device can be formed compactly, above the marine propulsion unit of the present embodiment, a first motor and a second motor are arranged such that the first motor shaft and the second motor shaft each extend in the vertical direction. Further, the second motor is arranged above the first motor. With such an arrangement, the upper end portion of the first motor shaft and the lower end portion of the second motor shaft can be brought closer to each other within the space between the first motor and the second motor. Also, the upper portion of the drive shaft passes through the first motor shaft and reaches between the first motor and the second motor. Thereby, the upper end portion of the drive shaft can be brought closer to each of the upper end portion of the first motor shaft and the lower end portion of the second motor shaft within the space between the first motor and the second motor. The power transmission device is arranged between the first motor and the second motor. The power transmission device transmits the first power output from the first motor shaft to the drive shaft by connecting the upper end portion of the first motor shaft and the upper end portion of the drive shaft and disconnecting the lower end portion of the second motor shaft and the upper end portion of the drive shaft within the space between the first motor and the second motor. Also, the power transmission device transmits the second power output from the second motor shaft to the drive shaft by connecting the lower end portion of the second motor shaft and the upper end portion of the drive shaft and disconnecting the upper end portion of the first motor shaft and the upper end portion of the drive shaft within the space between the first motor and the second motor. Since the upper end portion of the first motor shaft, the lower end portion of the second motor shaft, and the upper end portion of the drive shaft are arranged close to each other within the space between the first motor and the second motor, a power transmission device that switchably connects either the upper end portion of the first motor shaft or the lower end portion of the second motor shaft to the upper end portion of the drive shaft can be formed compactly.

Example

[0018] Hereinafter, as an example of the present invention, a case where the present invention is applied to an outboard motor, which is a form of a marine propulsion unit, will be described. In the description of this embodiment, when referring to the directions of up (Ud), down (Dd), front (Fd), rear (Bd), left (Ld), and right (Rd), follow the arrows drawn in the lower right of each figure.

[0019] (Outboard motor) FIG. 1 shows an outboard motor 1 according to an embodiment of the present invention. In FIG. 1, the outboard motor 1 includes a power unit 2, a propeller 3, a drive shaft 4, a propeller shaft 5, and a gear mechanism 6.

[0020] The power unit 2 generates power for propelling the ship. The power unit 2 is disposed at the upper part of the outboard motor 1 so as to be located above the water surface in a state where the outboard motor 1 is attached to the ship. Further, the power unit 2 is fixed to a motor holder 9 provided at the upper part of the outboard motor 1.

[0021] The propeller 3 converts the power generated by the power unit 2 into a propulsive force. The propeller 3 is disposed at the lower part of the outboard motor 1 so as to be located below the water surface in a state where the outboard motor 1 is attached to the ship.

[0022] The drive shaft 4, the propeller shaft 5, and the gear mechanism 6 transmit the power generated by the power unit 2 to the propeller 3. The drive shaft 4 extends vertically from the upper part to the lower part of the outboard motor 1. The upper part of the drive shaft 4 enters the interior of the power unit 2. The propeller shaft 5 is arranged at the lower part of the outboard motor 1 and extends in the front-rear direction. The propeller 3 is fixed to the rear part of the propeller shaft 5. The gear mechanism 6 is arranged at the front part of the lower part of the outboard motor 1. The gear mechanism 6 includes a drive gear 7 and a driven gear 8. The drive gear 7 is fixed to the lower end of the drive shaft 4, and the driven gear 8 is fixed to the front end of the propeller shaft 5. Both the drive gear 7 and the driven gear 8 are bevel gears. By the meshing of these gears, the rotation of the drive shaft 4 around the vertical axis is converted into the rotation of the propeller shaft 5 around the horizontal axis. The drive shaft 4 receives the power of the power unit 2 and rotates, and the rotation of the drive shaft 4 is transmitted to the propeller shaft 5 through the gear mechanism 6, whereby the propeller 3 rotates together with the propeller shaft 5.

[0023] In addition, at the upper part of the outboard motor 1, a motor cover 10 that covers the power unit 2 and the motor holder 9 is provided. The motor cover 10 is divided into a bottom cover 11 that covers the lower part of the power unit 2 and the motor holder 9, and a top cover 12 that covers the upper part of the power unit 2. Also, at the middle part in the vertical direction of the outboard motor 1, a drive shaft case 13 that covers the outer peripheral side of the drive shaft 4 is provided. Further, at the lower part of the outboard motor 1, a gear case 14 that covers the gear mechanism 6 and the front part of the propeller shaft 5 is provided. Moreover, the outboard motor 1 is provided with a clamp mechanism 15 for detachably fixing the outboard motor 1 to the hull of the ship.

[0024] (Power Unit) Figure 2 shows the power unit 2 and the motor holder 9 as seen from the upper left front. Figure 3 shows the power unit 2 and the motor holder 9 as seen from the left. Figure 4 shows the power unit 2 and the motor holder 9 as seen from the front. Figure 5 shows a cross-section of the power unit 2 cut along the cutting line V-V in Figure 4 as seen from the left (right in Figure 4).

[0025] As shown in Figure 2, the power unit 2 includes a lower motor 21, a lower inverter 35, an upper motor 41, an upper inverter 55, and a power transmission device 61.

[0026] The lower motor 21 is an alternating current electric motor, that is, an AC motor. As shown in Figure 5, the lower motor 21 includes a motor shaft 22, a rotor 23 provided on the outer peripheral side of the motor shaft 22, a stator 24 provided on the outer peripheral side of the rotor 23, and a cylindrical motor case 25 provided on the outer peripheral side of the stator 24. The rotor 23 rotates together with the motor shaft 22, and the stator 24 is fixed to the motor case 25. Further, the motor shaft 22 is formed in a cylindrical shape. In other words, a through hole penetrating in the axial direction is formed in the central portion of the motor shaft 22.

[0027] Furthermore, as shown in FIG. 2, the lower motor 21 includes a bottom motor bracket 26 and a top motor bracket 27. The bottom motor bracket 26 is formed in a polygonal or circular plate shape and is disposed below the motor case 25 so as to generally close the lower part of the motor case 25. The lower part of the motor case 25 is fixed to the bottom motor bracket 26. For example, a plurality of motor fixing portions 25A protruding outward are provided at the lower part of the motor case 25, and these motor fixing portions 25A are fixed to the bottom motor bracket 26. Also, as shown in FIG. 5, a motor shaft insertion hole 26A is formed at the center of the bottom motor bracket 26. The lower end portion of the motor shaft 22 is rotatably supported via a bearing 31 within the motor shaft insertion hole 26A. Also, as shown in FIG. 3, the bottom motor bracket 26 is provided on the upper surface of the front portion of the motor holder 9 and is fixed to the motor holder 9.

[0028] As shown in FIG. 2, the top motor bracket 27 is formed in a polygonal or circular plate shape and is disposed above the motor case 25 so as to generally close the upper part of the motor case 25. The upper part of the motor case 25 is fixed to the top motor bracket 27. For example, a plurality of motor fixing portions 25B protruding outward are provided at the upper part of the motor case 25, and these motor fixing portions 25B are fixed to the top motor bracket 27. Also, as shown in FIG. 5, a motor shaft insertion hole 27A is formed at the center of the top motor bracket 27. The upper end portion of the motor shaft 22 is rotatably supported via a bearing 32 within the motor shaft insertion hole 27A.

[0029] The lower inverter 35 is a device that converts the current supplied from the battery from direct current to alternating current in order to drive the lower motor 21. Inverter mounting portions 30 are provided at the left rear part and the right rear part of the bottom motor bracket 26, and at the left rear part and the right rear part of the top motor bracket 27. The lower inverter 35 is fixed to the rear part of the lower motor 21 by being mounted on the inverter mounting portions 30.

[0030] The upper motor 41 is an AC motor. In this embodiment, the upper motor 41 is the same as the lower motor 21 in terms of the basic configuration as an AC motor and the performance related to power generation such as output and torque. The upper motor 41 includes a motor shaft 42, a rotor 43, a stator 44, and a cylindrical motor case 45, substantially the same as the lower motor 21. However, the motor shaft 42 of the upper motor 41 is different from the motor shaft 22 of the lower motor 21 and is not cylindrical. That is, a through hole penetrating the central portion of the motor shaft 42 in the axial direction is not formed. For the purpose of reducing the weight of the motor shaft 42, etc., the motor shaft 42 may be formed in a cylindrical shape.

[0031] Also, the upper motor 41 includes a bottom motor bracket 46 and a top motor bracket 49. The bottom motor bracket 46 is formed in a polygonal or circular plate shape and is disposed below the motor case 45 so as to generally close the lower part of the motor case 45. The lower part of the motor case 45 is fixed to the bottom motor bracket 46 via a plurality of motor fixing portions 45A protruding outward from the lower part of the motor case 45. Further, a motor shaft insertion hole 46A is formed in the central portion of the bottom motor bracket 46. The lower end portion of the motor shaft 42 is rotatably supported in the motor shaft insertion hole 46A via a bearing 51.

[0032] The top motor bracket 49 is formed in a polygonal or circular plate shape and is disposed above the motor case 45 so as to generally close the upper part of the motor case 45. The upper part of the motor case 45 is fixed to the top motor bracket 49 via a plurality of motor fixing portions 45B protruding outward from the upper part of the motor case 45. Further, a motor shaft insertion hole 49A is formed in the central portion of the top motor bracket 49. The upper end portion of the motor shaft 42 is rotatably supported in the motor shaft insertion hole 49A via a bearing 52.

[0033] The upper inverter 55 is a device that converts the current supplied from the battery from direct current to alternating current in order to drive the upper motor 41. The upper inverter 55 is fixed to the rear part of the upper motor 41 by being attached to the inverter mounting portions 50 provided at the left rear and right rear portions of the bottom motor bracket 46 and the left rear and right rear portions of the top motor bracket 49.

[0034] The upper motor 41 is disposed above the lower motor 21. The lower motor 21 and the upper motor 41 are arranged such that the motor shafts 22 and 42 extend in the vertical direction respectively. The lower motor 21 and the upper motor 41 are arranged such that the motor shafts 22 and 42 are coaxial respectively.

[0035] As shown in FIGS. 2 to 5, the lower motor 21 and the upper motor 41 are connected to each other using a plurality of support members 85. Each support member 85 is formed of, for example, a metal material or the like and extends in the vertical direction. Each support member 85 is disposed between the top motor bracket 27 of the lower motor 21 and the bottom motor bracket 46 of the upper motor 41. The lower part of each support member 85 is fixed to the top motor bracket 27 of the lower motor 21, and the upper part of each support member 85 is fixed to the bottom motor bracket 46 of the upper motor 41. In this embodiment, a through hole penetrating in the axial direction is formed in the central portion of each support member 85. Further, through holes penetrating in the vertical direction are formed in the portions of the top motor bracket 27 of the lower motor 21 and the bottom motor bracket 46 of the upper motor 41 where each support member 85 is disposed. Each support member 85 is fixed between the top motor bracket 27 and the bottom motor bracket 46 by inserting a bolt 86 into each of the through holes of the support member 85, the top motor bracket 27 of the lower motor 21, and the bottom motor bracket 46 of the upper motor 41 and fastening a nut 87 to the end of the bolt 86. Thereby, the lower motor 21 and the upper motor 41 are connected.

[0036] The plurality of support members 85 are arranged on the outer peripheral side portions of the top motor bracket 27 and the bottom motor bracket 46, respectively. FIG. 6 shows a state of viewing from above a cross-section of the power unit 2 cut along the cutting line VI-VI in FIG. 3. As shown in FIG. 6, in the present embodiment, two of the seven support members 85 are arranged on the left portions of the top motor bracket 27 and the bottom motor bracket 46, another two support members 85 are arranged on the right portions of the top motor bracket 27 and the bottom motor bracket 46, and the remaining three support members 85 are arranged on the rear portions of the top motor bracket 27 and the bottom motor bracket 46.

[0037] A space is formed between the lower motor 21 and the upper motor 41 by the plurality of support members 85. As shown in FIG. 5, in the space between the lower motor 21 and the upper motor 41, the upper end portion of the motor shaft 22 of the lower motor 21 and the lower end portion of the motor shaft 42 of the upper motor 41 are arranged to face each other and approach each other.

[0038] Also, the upper portion of the drive shaft 4 is inserted into the inner peripheral side of the motor shaft 22 of the lower motor 21. The upper portion of the drive shaft 4 passes through the motor holder 9, passes through the inner peripheral side of the motor shaft 22 of the lower motor 21, and reaches the space between the lower motor 21 and the upper motor 41. And the upper end portion of the drive shaft 4 is close to the upper end portion of the motor shaft 22 of the lower motor 21 and the lower end portion of the motor shaft 42 of the upper motor 41, respectively.

[0039] Also, the inner diameter of the motor shaft 22 of the lower motor 21 is set to a value larger than the outer diameter of the upper portion of the drive shaft 4. The upper portion of the drive shaft 4 is inserted into the motor shaft 22 in a state where its outer peripheral surface is separated from the inner peripheral surface of the motor shaft 22 of the lower motor 21. Therefore, the drive shaft 4 can rotate independently of the motor shaft 22 of the lower motor 21.

[0040] Note that the lower motor 21 is a specific example of the "first motor", and the motor shaft 22 of the lower motor 21 is a specific example of the "first motor shaft". Also, the upper motor 41 is a specific example of the "second motor", and the motor shaft 42 of the upper motor 41 is a specific example of the "second motor shaft".

[0041] (Power transmission device) The power unit 2 includes a power transmission device 61 that transmits either both or one of the power of the lower motor 21, that is, the power output from the motor shaft 22 of the lower motor 21, and the power of the upper motor 41, that is, the power output from the motor shaft 42 of the upper motor 41, to the drive shaft 4. The power transmission device 61 has a function of switching the power transmitted to the drive shaft 4 between (a) both the power of the lower motor 21 and the power of the upper motor 41, (b) the power of the lower motor 21, and (c) the power of the upper motor 41.

[0042] FIG. 7 shows a state of the lower motor 21 and the upper motor 41 in the power unit 2 as viewed from the left. Note that in FIG. 7, each support member 85 is not shown. As shown in FIG. 7, the power transmission device 61 is disposed between the lower motor 21 and the upper motor 41. The power transmission device 61 includes a dog clutch 62, a lower fitting member 66, an upper fitting member 68, and a switching mechanism 71.

[0043] FIG. 8 shows the dog clutch 62, the lower fitting member 66, and the motor shaft 22 of the lower motor 21 in a separated state. As shown in FIG. 8, the dog clutch 62 is formed in a cylindrical shape. Also, as shown in FIG. 5, the dog clutch 62 is attached to the outer peripheral side of the upper end portion of the drive shaft 4 so as to be non-rotatable with respect to the drive shaft 4 and movable in the vertical direction with respect to the drive shaft 4.

[0044] As shown in FIG. 8, an upper fitting portion 64 is formed on the upper part of the dog clutch 62. Concavities and convexities are formed on the outer peripheral side of the upper fitting portion 64. Further, a lower fitting portion 63 is formed on the lower part of the dog clutch 62. Concavities and convexities similar to those formed on the outer peripheral side of the upper fitting portion 64 are formed on the outer peripheral side of the lower fitting portion 63. Further, a clutch groove 65 is formed on the outer peripheral surface of the intermediate portion in the vertical direction of the dog clutch 62. The clutch groove 65 extends over the entire circumference of the dog clutch 62.

[0045] The lower fitting member 66 is formed in a cylindrical shape. Further, as shown in FIG. 5, the lower fitting member 66 is fixedly attached to the upper end portion of the motor shaft 22 of the lower motor 21 so as not to rotate relative to the motor shaft 22. Specifically, a fitting member insertion portion 22A in which the inner diameter of the motor shaft 22 is enlarged compared to the inner diameter of other portions of the motor shaft 22 is formed at the upper end portion of the motor shaft 22 of the lower motor 21. The lower part of the lower fitting member 66 is inserted into the fitting member insertion portion 22A and fixed in the fitting member insertion portion 22A by a method such as spline coupling.

[0046] As shown in FIG. 8, a fitting portion 67 is formed on the upper part of the lower fitting member 66. Concavities and convexities are formed on the inner peripheral side of the fitting portion 67. The shape of the concavities and convexities of the lower fitting portion 63 of the dog clutch 62 and the shape of the concavities and convexities of the fitting portion 67 of the lower fitting member 66 are set so that the lower fitting portion 63 can be fitted into the fitting portion 67.

[0047] The upper fitting member 68 is formed in a cylindrical shape and is fixedly attached to the lower end portion of the motor shaft 42 of the upper motor 41 so as not to rotate relative to the motor shaft 42 as shown in FIG. 5. Specifically, a fitting member insertion portion 42A is formed at the lower end portion of the motor shaft 42 of the upper motor 41. The fitting member insertion portion 42A is a hole formed at the center of the lower end surface of the motor shaft 42. The upper part of the upper fitting member 68 is inserted into the fitting member insertion portion 42A and fixed in the fitting member insertion portion 42A by a method such as spline coupling.

[0048] A fitting portion 69 is formed at the lower part of the upper fitting member 68 (see Fig. 9(A)). Concavities and convexities are formed on the inner peripheral side of the fitting portion 69. The shapes of the concavities and convexities of the upper fitting portion 64 of the dog clutch 62 and the shapes of the concavities and convexities of the fitting portion 69 of the upper fitting member 68 are set so that the upper fitting portion 64 can be fitted into the fitting portion 69.

[0049] Note that, as the lower fitting member 66 and the upper fitting member 68, two common fitting members can be used. That is, one of the two common fitting members can be used as the lower fitting member 66 by fixing it in the fitting member insertion portion 22A of the motor shaft 22 of the lower motor 21 so that its fitting portion faces upward, and the other of the two common fitting members can be used as the upper fitting member 68 by fixing it in the fitting member insertion portion 42A of the motor shaft 42 of the upper motor 41 so that its fitting portion faces downward.

[0050] Also, the lower fitting portion 63 of the dog clutch 62 is a specific example of the "first fitting portion", and the upper fitting portion 64 of the dog clutch 62 is a specific example of the "second fitting portion". Also, the fitting portion 67 of the lower fitting member 66 is a specific example of the "first fitted portion", and the fitting portion 69 of the upper fitting member 68 is a specific example of the "second fitted portion".

[0051] Figs. 9(A) to 9(C) show the operation of the power transmission device 61. The dog clutch 62 cannot rotate with respect to the drive shaft 4, but can move in the vertical direction within a predetermined movement range with respect to the drive shaft 4. In this embodiment, as shown in Fig. 9(B), the dog clutch 62 can move in the vertical direction within a movement range from a position where the lower fitting portion 63 of the dog clutch 62 is deeply fitted into the fitting portion 67 of the lower fitting member 66 to a position where the upper fitting portion 64 of the dog clutch 62 is deeply fitted into the fitting portion 69 of the upper fitting member 68 as shown in Fig. 9(C).

[0052] As shown in FIG. 9(A), when the dog clutch 62 moves to the middle part within the above-mentioned movement range, the lower fitting part 63 of the dog clutch 62 fits with the fitting part 67 of the lower fitting member 66, and the upper fitting part 64 of the dog clutch 62 fits with the fitting part 69 of the upper fitting member 68. Thereby, the motor shaft 22 of the lower motor 21 and the drive shaft 4 are connected via the dog clutch 62, and at the same time, the motor shaft 42 of the upper motor 41 and the drive shaft 4 are connected via the dog clutch 62. As a result, the power of both the lower motor 21 and the upper motor 41 is transmitted to the drive shaft 4, and the drive shaft 4 rotates by the power of both the lower motor 21 and the upper motor 41, and the propeller 3 rotates by the power of both the lower motor 21 and the upper motor 41.

[0053] As shown in FIG. 9(B), when the dog clutch 62 moves to the lower part within the above-mentioned movement range, the lower fitting part 63 of the dog clutch 62 fits with the fitting part 67 of the lower fitting member 66, and the fitting between the upper fitting part 64 of the dog clutch 62 and the fitting part 69 of the upper fitting member 68 is released. Thereby, the motor shaft 22 of the lower motor 21 and the drive shaft 4 are connected via the dog clutch 62, and at the same time, the motor shaft 42 of the upper motor 41 and the drive shaft 4 are disconnected. As a result, among the two motors of the power unit 2, only the power of the lower motor 21 is transmitted to the drive shaft 4, the drive shaft 4 rotates only by the power of the lower motor 21, and the propeller 3 rotates only by the power of the lower motor 21.

[0054] As shown in Fig. 9(C), when the dog clutch 62 moves to the upper part within the above-mentioned movement range, the upper fitting portion 64 of the dog clutch 62 fits with the fitting portion 69 of the upper fitting member 68, and the fitting between the lower fitting portion 63 of the dog clutch 62 and the fitting portion 67 of the lower fitting member 66 is released. As a result, the motor shaft 42 of the upper motor 41 and the drive shaft 4 are connected via the dog clutch 62, and at the same time, the connection between the motor shaft 22 of the lower motor 21 and the drive shaft 4 is cut off. As a result, among the two motors of the power unit 2, only the power of the upper motor 41 is transmitted to the drive shaft 4, the drive shaft 4 rotates only by the power of the upper motor 41, and the propeller 3 rotates only by the power of the upper motor 41.

[0055] (Switching mechanism) The power transmission device 61 includes a switching mechanism 71 that switches the power transmitted to the drive shaft 4 between (a) both the power of the lower motor 21 and the power of the upper motor 41, (b) the power of the lower motor 21, and (c) the power of the upper motor 41 by moving the dog clutch 62 based on an external operation input. Fig. 10 shows a state in which the components of the switching mechanism 71 are disassembled. As shown in Fig. 10, the switching mechanism 71 includes a clutch rod 72, a first joint member 73, a clutch link 74, a second joint member 75, a clutch cam shaft 76, and a fork unit 78.

[0056] One end of a first joint member 73 is non-rotatably connected to the clutch rod 72. One end of a clutch link 74 is rotatably connected to the other end of the first joint member 73. One end of a second joint member 75 is rotatably connected to the other end of the clutch link 74. The other end of the second joint member 75 is non-rotatably connected to the upper portion of a clutch camshaft 76. The clutch camshaft 76 has a structure of a cylindrical cam, and a cam groove 77 is formed on the outer peripheral surface of the middle portion in the vertical direction of the clutch camshaft 76. The middle portion in the vertical direction of the clutch camshaft 76 is inserted into the inner peripheral side of a cylindrical portion 79 of a fork unit 78. A driven pin 81 is inserted into a pin hole 79A formed in the cylindrical portion 79 of the fork unit 78. The driven pin 81 penetrates through the pin hole 79A, and the tip of the driven pin 81 is inserted into the cam groove 77 inside the cylindrical portion 79. The driven pin 81 inserted into the pin hole 79A is fixed to the cylindrical portion 79 of the fork unit 78 by a stopper member 83 with a coil spring 82 interposed therebetween. A fork 80 is formed on the cylindrical portion 79 of the fork unit 78. The fork 80 protrudes radially outward from the cylindrical portion 79. The tip of the fork 80 is inserted into a clutch groove 65 of a dog clutch 62 as shown in FIGS. 5 to 7. The tip of the fork 80 is inserted into the clutch groove 65 with a gap therebetween so that the dog clutch 62 can rotate as the drive shaft 4 rotates with the tip of the fork 80 inserted into the clutch groove 65.

[0057] In FIG. 10, when the clutch rod 72 rotates in the direction of arrow A, the rotation is transmitted to the clutch camshaft 76 via the first joint member 73, the clutch link 74, and the second joint member 75, and the clutch camshaft 76 rotates in the direction of arrow C. Due to the rotation of this clutch camshaft 76, the fork unit 78 moves upward, for example. When the fork unit 78 moves upward, the dog clutch 62 moves upward. On the other hand, when the clutch rod 72 rotates in the direction of arrow B, the rotation is transmitted to the clutch camshaft 76 via the first joint member 73, the clutch link 74, and the second joint member 75, and the clutch camshaft 76 rotates in the direction of arrow D. Due to the rotation of this clutch camshaft 76, the fork unit 78 moves downward, for example. When the fork unit 78 moves downward, the dog clutch 62 moves downward. Note that the relationship between the rotation direction of the clutch rod 72 and the moving direction of the fork unit 78 in the vertical direction, and the relationship between the rotation amount of the clutch rod 72 and the moving amount of the fork unit 78 in the vertical direction can be set according to the shape of the cam groove 77 formed in the clutch camshaft 76.

[0058] Also, as shown in FIG. 2, the clutch rod 72 is rotatably supported between a rod support portion 28 provided at the right front portion of the top motor bracket 27 of the lower motor 21 and a rod support portion 47 provided at the right front portion of the bottom motor bracket 46 of the upper motor 41. Further, the clutch camshaft 76 is rotatably supported between a camshaft support portion 29 provided at the left front portion of the top motor bracket 27 of the lower motor 21 and a camshaft support portion 48 provided at the left front portion of the bottom motor bracket 46 of the upper motor 41.

[0059] Although illustration is omitted, an actuator (e.g., a DC motor) for rotating the clutch rod 72 is provided at the upper part of the outboard motor 1, and the output shaft of the actuator is connected to the clutch rod 72. Further, an external operation input for moving the dog clutch 62 is input to the actuator. Based on the external operation input, the actuator operates, the clutch rod 72 rotates, and the dog clutch 62 moves.

[0060] As described above, the outboard motor 1 of the embodiment of the present invention has a power unit 2 including a lower motor 21, an upper motor 41, and a power transmission device 61. The power transmission device 61 transmits both or either one of the power of the lower motor 21 and the power of the upper motor 41 to the drive shaft 4, and the power transmitted to the drive shaft 4 can be switched between (a) both the power of the lower motor 21 and the power of the upper motor 41, (b) the power of the lower motor 21, and (c) the power of the upper motor. According to this configuration, when the lower motor 21 fails, only the power of the upper motor 41 is transmitted to the drive shaft 4, so that the propulsion force of the ship can be generated by the power of the upper motor 41, and the ship can be moved. Further, when the upper motor 41 fails, only the power of the lower motor 21 is transmitted to the drive shaft 4, so that the propulsion force of the ship can be generated by the power of the lower motor 21, and the ship can be moved. Therefore, according to the outboard motor 1 of the embodiment of the present invention, the possibility that the movement of the ship becomes difficult when the motor that generates the propulsion force of the ship fails during navigation can be reduced.

[0061] Further, according to the outboard motor 1 of the embodiment of the present invention, by switching the power transmitted to the drive shaft 4 by the power transmission device 61, the output of the power unit 2 can be significantly changed, or the power consumption of the power unit 2 can be adjusted. For example, by switching from a state where only the power of the lower motor 21 or only the power of the upper motor 41 is transmitted to the drive shaft 4 to a state where both the power of the lower motor 21 and the power of the upper motor 41 are transmitted to the drive shaft 4, the output of the power unit 2 can be significantly increased. Also, by switching from a state where both the power of the lower motor 21 and the power of the upper motor 41 are transmitted to the drive shaft 4 to a state where only the power of the lower motor 21 or only the power of the upper motor 41 is transmitted to the drive shaft 4, the power consumption of the power unit 2 can be reduced.

[0062] Further, according to the outboard motor 1 of the embodiment of the present invention, when applying a regenerative brake using the rotational force of the propeller 3 after the drive of the motor is stopped, the motor shaft connected to the drive shaft 4 via the dog clutch 62 can be only the motor shaft 22 of the lower motor 21 or only the motor shaft 42 of the upper motor 41. Thereby, compared with the case where the motor shaft connected to the drive shaft 4 via the dog clutch 62 is both the motor shafts 22 and 42, the resistance inside the outboard motor 1 that reduces the rotational force of the propeller 3 can be reduced. Therefore, after the drive of the motor is stopped, the rotation of the propeller 3 can be sustained to a low speed range, and the time during which the regenerative brake can be used can be lengthened.

[0063] In addition, in the outboard motor 1 according to the embodiment of the present invention, the lower motor 21 and the upper motor 41 are arranged at the upper part of the outboard motor 1. The motor shaft 22 of the lower motor 21, the motor shaft 42 of the upper motor 41, and the drive shaft 4 each extend in the vertical direction. The upper motor 41 is arranged above the lower motor 21. The upper part of the drive shaft 4 passes through the motor shaft 22 of the lower motor 21 independently rotatably and reaches between the lower motor 21 and the upper motor 41. The power transmission device 61 is arranged between the lower motor 21 and the upper motor 41. With this configuration, it is possible to prevent the outboard motor 1 from being significantly enlarged due to the provision of the lower motor 21, the upper motor 41, and the power transmission device 61 in the outboard motor 1.

[0064] Specifically, by arranging the lower motor 21 and the upper motor 41 side by side in the vertical direction so that the motor shafts 22 and 42 extend in the vertical direction respectively, the upper end of the motor shaft 22 of the lower motor 21 and the lower end of the motor shaft 42 of the upper motor 41 can be brought close to each other in the space between the lower motor 21 and the upper motor 41. Further, by arranging the drive shaft 4 so that its upper part passes through the motor shaft 22 of the lower motor 21 and reaches between the lower motor 21 and the upper motor 41, the upper end of the drive shaft 4 can be brought close to the upper end of the motor shaft 22 of the lower motor 21 and the lower end of the motor shaft 42 of the upper motor 41 respectively in the space between the lower motor 21 and the upper motor 41. Then, by arranging the power transmission device 61 that switches the connection and disconnection of the upper end of the motor shaft 22, the lower end of the motor shaft 42, and the upper end of the drive shaft 4, which are close to each other, between the lower motor 21 and the upper motor 41, the power transmission device 61 can be formed compactly. That is, since the upper end of the motor shaft 22, the lower end of the motor shaft 42, and the upper end of the drive shaft 4 are close to each other, the dog clutch 62 and the switching mechanism 71 can be made smaller and can be arranged intensively.

[0065] According to the outboard motor 1 of this embodiment, it is possible to prevent the upper part of the outboard motor 1 from becoming significantly larger, so that the air resistance during navigation can be suppressed, and the stability of the attachment of the outboard motor 1 to the hull can be suppressed from decreasing. Furthermore, it is possible to prevent the appearance of the outboard motor 1 from deteriorating. Also, in the outboard motor 1 of this embodiment, since the lower motor 21, the upper motor 41, and the power transmission device 61 are all arranged at the upper part of the outboard motor 1, it is possible to suppress the enlargement of the lower part of the outboard motor 1 and prevent the water resistance during the navigation of the ship from increasing.

[0066] Also, in the outboard motor 1 of this embodiment, the upper end portion of the motor shaft 22 of the lower motor 21 and the lower end portion of the motor shaft 42 of the upper motor 41 face each other. A lower fitting member 66 is fixed to the upper end portion of the motor shaft 22, and an upper fitting member 68 is fixed to the lower end portion of the motor shaft 42. The upper end portion of the drive shaft 4 is arranged between the upper end portion of the motor shaft 22 of the lower motor 21 and the lower end portion of the motor shaft 42 of the upper motor 41, and a dog clutch 62 is provided at the upper end portion of the drive shaft 4. With this configuration, a power transmission device 61 that transmits the power of the lower motor 21 and the power of the upper motor 41 to the drive shaft 4 in a switchable manner can be made into a simple configuration, and the power transmission device 61 can be easily formed.

[0067] Also, in the outboard motor 1 of this embodiment, the upper part of the drive shaft 4 is configured to pass through the inner peripheral side of the cylindrical motor shaft 22 of the lower motor 21 and reach between the lower motor 21 and the upper motor 41. With this configuration, a structure in which the upper end portion of the drive shaft 4 is arranged between the upper end portion of the motor shaft 22 of the lower motor 21 and the lower end portion of the motor shaft 42 of the upper motor 41 can be formed compactly, and the power unit 2 can be miniaturized.

[0068] In the above-described embodiment, the power transmitted to the drive shaft 4 by the power transmission device 61 is taken as an example of switching between (a) the power of the lower motor 21 and the power of the upper motor 41, (b) the power of the lower motor 21, and (c) the power of the upper motor. However, the present invention is not limited to this. The switching of the power transmitted to the drive shaft 4 by the power transmission device may be performed only between (a) and (b) above, only between (a) and (c) above, or only between (b) and (c) above.

[0069] In the above-described embodiment, the lower motor 21 and the upper motor 41 having the same performance regarding power generation such as output and torque are provided in the power unit 2. However, the performance regarding power generation such as output and torque may be made different between the lower motor 21 and the upper motor 41.

[0070] In the above-described embodiment, the case where the lower fitting member 66 is fixed to the upper end portion of the motor shaft 22 of the lower motor 21 to provide a fitting portion that fits with the fitting portion of the dog clutch at the upper portion of the motor shaft 22 is taken as an example. However, the present invention is not limited to this. For example, a fitting portion that fits with the fitting portion of the dog clutch may be integrally formed at the upper end portion of the motor shaft 22. Similarly, for the motor shaft 42 of the upper motor 41, a fitting portion that fits with the fitting portion of the dog clutch may be integrally formed at the lower end portion of the motor shaft 42.

[0071] In the present invention, the type of motor used in the power unit is not limited, and for example, a DC motor may be used. Further, the present invention can also be applied to marine propulsion devices other than outboard motors.

[0072] Further, the present invention can be appropriately modified within the scope not contrary to the gist or idea of the invention that can be read from the claims and the entire specification, and a marine propulsion device with such modifications is also included in the technical idea of the present invention.

Explanation of Reference Numerals

[0073] 1 Outboard motor (marine propulsion device) 2 Power unit 3 Propellers 4 Drive Shafts 21 Lower Motor (First Motor) 22 Motor Shaft (First Motor Shaft) 41 Upper Motor (Second Motor) 42 Motor Shaft (Second Motor Shaft) 61 Power Transmission Device 62 Dog Clutch 63 Lower Fitting Portion (First Fitting Portion) 64 Upper Fitting Portion (Second Fitting Portion) 66 Lower Fitted Member 67 Fitted Portion (First Fitted Portion) 68 Upper Fitted Member 69 Fitted Portion (Second Fitted Portion)

Claims

1. A marine propulsion unit comprising a power unit for generating power, a propeller, and a drive shaft for transmitting the power generated by the power unit to the propeller, wherein the power unit includes a first motor having a first motor shaft, a second motor having a second motor shaft, and a power transmission device that transmits either the first power output from the first motor shaft or the second power output from the second motor shaft to the drive shaft and switches the power transmitted to the drive shaft between the first power and the second power, wherein the first motor and the second motor are disposed at the upper part of the marine propulsion unit, wherein the first motor shaft, the second motor shaft, and the drive shaft each extend in the vertical direction, wherein the second motor is disposed above the first motor, wherein the upper part of the drive shaft is rotatable independently of the first motor shaft and passes through the first motor shaft to reach between the first motor and the second motor, and wherein the power transmission device is disposed between the first motor and the second motor. A marine propulsion unit characterized by this.

2. The marine propulsion unit according to claim 1, wherein the power transmission device transmits either both or either one of the first power and the second power to the drive shaft and switches the power transmitted to the drive shaft between (a) both the first power and the second power, (b) the first power, and (c) the second power.

3. The power transmission device includes a dog clutch, wherein the dog clutch is attached to the upper part of the drive shaft so as to be non-rotatable with respect to the drive shaft and movable in the vertical direction with respect to the drive shaft, wherein a first fitting portion is provided at the lower part of the dog clutch, wherein a second fitting portion is provided at the upper part of the dog clutch, wherein a first fitted portion is provided at the upper part of the first motor shaft, and wherein a second fitted portion is provided at the lower part of the second motor shaft. When the dog clutch moves downward, the first fitting portion fits with the first fitted portion and the fitting between the second fitting portion and the second fitted portion is released. When the dog clutch moves upward, the second fitting portion fits with the second fitted portion and the fitting between the first fitting portion and the first fitted portion is released. The marine propulsion device according to claim 1, characterized in that.

4. The power transmission device includes a dog clutch, The dog clutch is attached to the upper part of the drive shaft so as to be non-rotatable with respect to the drive shaft and movable within a predetermined range in the vertical direction with respect to the drive shaft. A first fitting portion is provided at the lower part of the dog clutch. A second fitting portion is provided at the upper part of the dog clutch. A first fitted portion is provided at the upper part of the first motor shaft. A second fitted portion is provided at the lower part of the second motor shaft. When the dog clutch moves to the lower part within the movement range, the first fitting portion fits with the first fitted portion and the fitting between the second fitting portion and the second fitted portion is released. When the dog clutch moves to the upper part within the movement range, the second fitting portion fits with the second fitted portion and the fitting between the first fitting portion and the first fitted portion is released. When the dog clutch moves to the middle part within the movement range, the first fitting portion fits with the first fitted portion and the second fitting portion fits with the second fitted portion. The marine propulsion device according to claim 2, characterized in that.

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