Ship propulsion machine

Abstract

To provide a ship propulsion machine that enables switching between a mode in which a propeller is rotated by a force obtained by combining power of two motors and a mode in which the propeller is rotated by power of one motor, while 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 switching device 61. The power switching device 61 connects a motor shaft 22 of the lower motor 21 with a motor shaft 42 of the upper motor 41 in a manner which enables disconnection therebetween and switches a state of the power unit 2 between a mode in which the two motor shafts 22, 42 are connected and a mode in which the two motor shafts 22, 42 are disconnected. The respective motors 21, 41 are arranged in an upper part of the outboard engine, and the respective motor shafts 22, 42 and a drive shaft 4 extend in a vertical direction. An upper part of the drive shaft 4 is connected to the motor shaft 22, and the power switching 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 device 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 disposed in the lower part of the outboard motor, when a large-sized 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, in this type of outboard motor, it is difficult to increase the output of the outboard motor by adopting a large-sized motor.

[0003] On the other hand, as described in Japanese Patent Application Laid-Open No. 2005-153727 (Patent Document 1), there is known an outboard motor 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-sized motor is adopted, it is possible to suppress the increase in the lower part of the outboard motor. Therefore, it is easy to adopt a large-sized motor, and the output of the outboard motor can be increased by adopting a large-sized motor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, if two motors are provided in a ship propulsion machine and the propeller is rotated by the combined force of the power output from the two motors respectively to generate the propulsion force of the ship, the output of the ship propulsion machine can be increased. Furthermore, by providing a power switching device in the ship propulsion machine that switches between a method of rotating the propeller by the combined force of the power of two motors and a method of rotating the propeller by the power of one motor, for example, it becomes easier to significantly increase or decrease the output of the ship propulsion machine or adjust the electricity cost, and the performance of the ship propulsion machine can be improved.

[0006] However, when two motors and a power switching device are provided in a ship propulsion machine, there is a risk that the ship propulsion machine will become significantly larger in size compared to a ship propulsion machine provided with only one motor as a power source for generating the propulsion force of the ship. For example, when two motors and a power switching device are provided at the lower part of an outboard motor, the lower part of the outboard motor will become significantly larger, and there is a risk that the water resistance during navigation will increase. Also, even when two motors and a power switching device are provided at the upper part of the outboard motor, the upper part of the outboard motor will become significantly larger, the air resistance during navigation will increase, the stability of the attachment of the outboard motor to the hull will decrease, or there is a risk that the appearance of the outboard motor will deteriorate.

[0007] 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 ship propulsion machine that can prevent the ship propulsion machine from becoming significantly larger in size while enabling switching between a method of rotating the propeller by the combined force of the power of two motors and a method of rotating the propeller by the power of one motor.

Means for Solving the Problems

[0008] 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 switching device that connectably disconnects the first motor shaft and the second motor shaft from each other and switches between a state where the first motor shaft and the second motor shaft are connected to each other and a state where the first motor shaft and the second motor shaft are disconnected from each other. The first motor and the second motor are disposed above 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 disposed above the first motor. The upper part of the drive shaft is connected to the first motor shaft. The power switching device is disposed between the first motor and the second motor.

Advantages of the Invention

[0009] According to the present invention, while preventing the significant enlargement of the marine propulsion unit, it is possible to provide the marine propulsion unit with a function of switching between a method of rotating the propeller by combining the power of two motors and a method of rotating the propeller by the power of one motor.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

[0011] The marine propulsion device according to an 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.

[0012] In the marine propulsion device 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 switching device. The power switching device connects the first motor shaft and the second motor shaft to be disconnectable from each other. Further, the power switching device switches between a state in which the first motor shaft and the second motor shaft are connected to each other and a state in which the first motor shaft and the second motor shaft are disconnected from each other.

[0013] In the ship propulsion unit of the present embodiment, the first motor and the second motor are arranged at the upper part of the ship propulsion unit. Also, 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. Also, the upper part of the drive shaft is connected to the first motor shaft. Also, the power switching device is arranged between the first motor and the second motor.

[0014] According to the ship propulsion unit of the present embodiment, the ship propulsion unit can be provided with a function of switching between a method of rotating the propeller by the combined power of two motors and a method of rotating the propeller by the power of one motor. Specifically, the ship propulsion unit of the present embodiment includes a power switching device that switches between a state in which the first motor shaft and the second motor shaft are connected to each other and a state in which the first motor shaft and the second motor shaft are disconnected from each other, and the upper part of the drive shaft is connected to the first motor shaft. When the power switching device switches the first motor shaft and the second motor shaft to a state in which they are connected to each other, the first motor shaft is directly connected to the drive shaft, and the second motor shaft is connected to the drive shaft via the first motor shaft. Thereby, the propeller can be rotated by the combined power of the power of the first motor and the power of the second motor. On the other hand, when the power switching device switches the first motor shaft and the second motor shaft to a state in which they are disconnected from each other, the first motor shaft is connected to the drive shaft, and the second motor shaft is no longer connected to the drive shaft. Thereby, the propeller can be rotated only by the power of the first motor.

[0015] Moreover, according to the marine propulsion unit of the present embodiment, it is possible to prevent the significant enlargement of the marine propulsion unit due to the provision of two motors and a power switching device in the marine propulsion unit. 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 switching device between the first motor and the second motor, the power switching device can be formed compactly. That is, the first motor and the second motor are arranged above the marine propulsion unit such that the first motor shaft and the second motor shaft each extend in the vertical direction, and by arranging the second motor above the first motor, 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. Then, by configuring the power switching device to be arranged between the first motor and the second motor and to connect the upper end portion of the first motor shaft and the lower end portion of the second motor, which are close to each other within the space between the first motor and the second motor, so as to be disconnectable from each other, the power switching device can be formed compactly. Therefore, according to the marine propulsion unit of the present embodiment, it is possible to reduce the degree of enlargement of the marine propulsion unit compared to a marine propulsion unit having only one motor.

Example

[0016] Hereinafter, as an example of the present invention, a case where the present invention is applied to an outboard motor, which is one form of a marine propulsion unit, will be described. In the description of this example, when describing the directions of up (Ud), down (Dd), front (Fd), rear (Bd), left (Ld), and right (Rd), follow the arrows drawn at the lower right in each figure.

[0017] (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.

[0018] The power unit 2 generates the power to propel the ship. The power unit 2 is arranged on 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 on the upper part of the outboard motor 1.

[0019] The propeller 3 converts the power generated by the power unit 2 into a propulsive force. The propeller 3 is arranged on 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.

[0020] 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 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 part of the drive shaft 4, and the driven gear 8 is fixed to the front end part 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 via the gear mechanism 6, whereby the propeller 3 rotates together with the propeller shaft 5.

[0021] In addition, on 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, on 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, on 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.

[0022] (Power Unit) Figure 2 shows the state of the power unit 2 and the motor holder 9 as seen from the upper left front. Figure 3 shows the state of the power unit 2 and the motor holder 9 as seen from the left. Figure 4 shows the state of the power unit 2 and the motor holder 9 as seen from the front. Figure 5 shows the 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).

[0023] 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 switching device 61.

[0024] The lower motor 21 is an alternating current type 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.

[0025] Also, 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. Further, 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.

[0026] 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, as shown in FIG. 2. 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. Further, 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.

[0027] The lower inverter 35 is a device that converts the current supplied from the battery to drive the lower motor 21 from direct current to alternating current. Inverter mounting portions 30 are provided at the left rear and right rear portions of the bottom motor bracket 26 and at the left rear and right rear portions of the top motor bracket 27. The lower inverter 35 is fixed to the rear portion of the lower motor 21 by being mounted on the inverter mounting portions 30.

[0028] 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 in the same manner as the lower motor 21.

[0029] 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 at the center 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.

[0030] 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 at the center 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.

[0031] The upper inverter 55 is a device that converts the current supplied from the battery from DC to AC 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 inverter attachment portions 50 provided at the left rear part and the right rear part of the bottom motor bracket 46 and the left rear part and the right rear part of the top motor bracket 49.

[0032] The upper motor 41 is disposed above the lower motor 21. The lower motor 21 and the upper motor 41 are each disposed such that the motor shafts 22 and 42 extend in the vertical direction. Also, the lower motor 21 and the upper motor 41 are each disposed such that the motor shafts 22 and 42 are coaxial.

[0033] 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 portion of each support member 85 is fixed to the top motor bracket 27 of the lower motor 21, and the upper portion of each support member 85 is fixed to the bottom motor bracket 46 of the upper motor 41. In the present embodiment, a through hole penetrating in the axial direction is formed in the central portion of each support member 85. Also, through holes penetrating in the vertical direction are formed in 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.

[0034] 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.

[0035] 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.

[0036] Also, each of the motor shafts 22, 42 is arranged coaxially with the drive shaft 4. Further, the upper end portion of the drive shaft 4 is connected to the lower end portion of the motor shaft 22 of the lower motor 21. The motor shaft 22 and the drive shaft 4 are coupled to be non-rotatable relative to each other by means such as spline coupling.

[0037] 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".

[0038] (Power switching device) The power unit 2 is provided with a power switching device 61 that detachably connects the motor shaft 22 of the lower motor 21 and the motor shaft 42 of the upper motor 41 to each other. The power switching device 61 has a function of switching between a state in which the motor shaft 22 of the lower motor 21 and the motor shaft 42 of the upper motor 41 are connected to each other and a state in which the motor shaft 22 of the lower motor 21 and the motor shaft 42 of the upper motor 41 are disconnected from each other.

[0039] FIG. 7 shows a state of looking at the space between the lower motor 21 and the upper motor 41 in the power unit 2 from the left. In FIG. 7, each support member 85 is not shown. As shown in FIG. 7, the power switching device 61 is disposed between the lower motor 21 and the upper motor 41. The power switching device 61 includes a connecting shaft 62 and a switching mechanism 71.

[0040] The connecting shaft 62 is a shaft having a circular cross-sectional shape formed of, for example, a metal material. The connecting shaft 62 is disposed 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 as shown in FIG. 5. Further, the connecting shaft 62 is disposed such that its axis extends in the vertical direction and is coaxial with each of the motor shafts 22 and 42. Note that the connecting shaft 62 is a specific example of a "connecting member".

[0041] FIG. 8(A) shows a state of looking at the connecting shaft 62 obliquely from below. As shown in FIG. 8(A), a coupling portion 63 is formed at the upper end portion of the connecting shaft 62. Splines are formed on the outer peripheral surface of the coupling portion 63. Further, a fitting portion 65 is formed above the lower end portion 64 at the lower portion of the connecting shaft 62. Concavities and convexities are formed on the lower surface of the fitting portion 65. Further, lower flange portions 66 and upper flange portions 67 are arranged in the vertical direction with a space therebetween at an intermediate portion in the axial direction of the connecting shaft 62. The lower flange portions 66 and the upper flange portions 67 each project radially outward from the outer peripheral surface of the connecting shaft 62. Further, a fork insertion portion 68 is formed between the lower flange portion 66 and the upper flange portion 67.

[0042] As shown in Fig. 5, a coupling shaft coupling hole 53 is formed in the lower end surface of the motor shaft 42 of the upper motor 41. Splines are formed on the inner peripheral surface of the coupling shaft coupling hole 53. The coupling portion 63 of the coupling shaft 62 is inserted into the coupling shaft coupling hole 53. Thereby, the upper end portion of the coupling shaft 62 is spline-coupled to the motor shaft 42 of the upper motor 41. However, the coupling shaft 62 cannot rotate relative to the motor shaft 42 of the upper motor 41, but can move in the vertical direction relative to the motor shaft 42. The shape of the splines formed on the coupling portion 63 of the coupling shaft 62 and the shape of the splines formed on the coupling shaft coupling hole 53 are set so that the coupling shaft 62 can move in the vertical direction relative to the motor shaft 42 while being non-rotatably coupled to the motor shaft 42.

[0043] Further, a coupling shaft insertion hole 33 is formed in the upper surface of the motor shaft 22 of the lower motor 21. The lower end portion 64 of the coupling shaft 62 is inserted into the coupling shaft insertion hole 33. The diameter of the coupling shaft insertion hole 33 is set to a value slightly larger than the diameter of the lower end portion 64 of the coupling shaft 62. Note that no splines are formed on the outer peripheral surface of the lower end portion 64 of the coupling shaft 62 nor on the inner peripheral surface of the coupling shaft insertion hole 33. The outer peripheral surface of the lower end portion 64 of the coupling shaft 62 does not contact the inner peripheral surface of the coupling shaft insertion hole 33.

[0044] Further, the distance between the bottom surface of the coupling shaft coupling hole 53 and the bottom surface of the coupling shaft insertion hole 33 is set to a value larger than the axial length of the coupling shaft 62. The coupling shaft 62 can move in the vertical direction while maintaining the state where the coupling portion 63 is inserted into the coupling shaft coupling hole 53 and the lower end portion 64 is inserted into the coupling shaft insertion hole 33.

[0045] FIG. 8(B) shows a state of viewing the upper end portion of the motor shaft 22 of the lower motor 21 obliquely from above. As shown in FIG. 8(B), a fitting portion 34 is formed on the outer peripheral portion of the upper end surface of the motor shaft 22 of the lower motor 21, that is, on the outer peripheral side of the opening of the connecting shaft insertion hole 33. Concavities and convexities are formed on the upper surface of the fitting portion 34. The shapes of the concavities and convexities formed on the fitting portion 65 of the connecting shaft 62 and the shapes of the concavities and convexities formed on the fitting portion 34 of the motor shaft 22 of the lower motor 21 are respectively set so that the fitting portion 65 and the fitting portion 34 can be fitted to each other.

[0046] FIGS. 9(A) and 9(B) show the operation of the power switching device 61. As shown in FIG. 9(A), when the connecting shaft 62 moves downward, the fitting portion 65 of the connecting shaft 62 is fitted to the fitting portion 34 of the motor shaft 22 of the lower motor 21. At this time, the coupling portion 63 of the connecting shaft 62 is inserted into the connecting shaft coupling hole 53 of the motor shaft 42 of the upper motor 41 and the state of being spline-coupled to the motor shaft 42 is maintained. As a result, the motor shaft 42 of the upper motor 41 is connected to the motor shaft 22 of the lower motor 21. In this state, the motor shaft 22 of the lower motor 21 is directly connected to the drive shaft 4, and the motor shaft 42 of the upper motor 41 is connected to the drive shaft 4 via the motor shaft 22 of the lower motor 21. Therefore, the power of both the lower motor 21 and the upper motor 41 is transmitted to the drive shaft 4. Therefore, the propeller 3 rotates by the combined force of the power of the lower motor 21 and the power of the upper motor 41.

[0047] On the one hand, as shown in Fig. 9(B), when the connecting shaft 62 moves upward, the fitting between the fitting portion 65 of the connecting shaft 62 and the fitted portion 34 of the motor shaft 22 of the lower motor 21 is released. As a result, the motor shaft 42 of the upper motor 41 is separated from the motor shaft 22 of the lower motor 21. In this state, since the motor shaft 22 of the lower motor 21 is connected to the drive shaft 4 and the motor shaft 42 of the upper motor 41 is not connected to the drive shaft 4, the power of the lower motor 21 is transmitted to the drive shaft 4 and the power of the upper motor 41 is not transmitted to the drive shaft 4. Therefore, among the two motors of the power unit 2, only the power of the lower motor 21 rotates the propeller 3.

[0048] (Switching mechanism) The power switching device 61 includes a switching mechanism 71 that switches between a state where the motor shaft 22 of the lower motor 21 and the motor shaft 42 of the upper motor 41 are connected to each other and a state where the motor shaft 22 of the lower motor 21 and the motor shaft 42 of the upper motor 41 are disconnected from each other by moving the connecting shaft 62 based on an external operation input. Fig. 8(C) shows a state in which the components of the switching mechanism 71 are disassembled. As shown in Fig. 8(C), 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.

[0049] One end of a first joint member 73 is non-rotatably connected to a 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 an 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 an outer peripheral surface of an intermediate portion in the vertical direction of the clutch camshaft 76. The intermediate portion in the vertical direction of the clutch camshaft 76 is inserted into an 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 a tip end portion of the driven pin 81 is inserted into the cam groove 77 within 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. A tip end portion of the fork 80 is inserted into a fork insertion portion 68 of a connecting shaft 62 as shown in FIGS. 5 to 7. The tip end portion of the fork 80 is inserted into the fork insertion portion 68 with a gap therebetween so that the connecting shaft 62 can rotate as the motor shaft 42 rotates in a state where the tip end portion of the fork 80 is inserted into the fork insertion portion 68.

[0050] In Fig. 8(C), 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 connecting shaft 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 connecting shaft 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 by the shape of the cam groove 77 formed in the clutch camshaft 76.

[0051] 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.

[0052] Although illustration is omitted, an actuator (for example, a DC motor) for rotating the clutch rod 72 is provided above 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 connecting shaft 62 is input to the actuator. Based on the external operation input, the actuator operates, the clutch rod 72 rotates, and the connecting shaft 62 moves.

[0053] As described above, the power unit 2 of the outboard motor 1 according to the embodiment of the present invention includes a lower motor 21, an upper motor 41, and a power switching device 61, and a drive shaft 4 is connected to the motor shaft 22 of the lower motor 21. The power switching device 61 connects the motor shaft 22 of the lower motor 21 and the motor shaft 42 of the upper motor 41 so as to be disconnectable from each other, and switches between a state in which the motor shaft 22 and the motor shaft 42 are connected to each other and a state in which the motor shaft 22 and the motor shaft 42 are disconnected from each other. With this configuration, the outboard motor 1 can be provided with a function of switching between a method of rotating the propeller 3 by the combined power of both the lower motor 21 and the upper motor 41 and a method of rotating the propeller 3 by only the power of the lower motor 21.

[0054] According to this function, the output of the power unit 2 can be significantly changed according to the navigation status of the ship, etc. For example, by switching the method of rotating the propeller 3 from the method of rotating the propeller 3 only by the power of the lower motor 21 to the method of rotating the propeller 3 by the combined power of both the lower motor 21 and the upper motor 41, the output of the power unit 2, and thus the propulsion force of the ship generated by the outboard motor 1, can be significantly increased. Also, by the above function, the electricity cost of the power unit 2 can be adjusted. For example, by switching the method of rotating the propeller 3 from the method of rotating the propeller 3 by the combined power of both the lower motor 21 and the upper motor 41 to the method of rotating the propeller 3 only by the power of the lower motor 21, the electricity cost of the power unit 2 can be reduced. Further, according to the above function, when the upper motor 41 fails during navigation, by switching the method of rotating the propeller 3 to the method of rotating the propeller 3 only by the power of the lower motor 21, the navigation of the ship can be continued.

[0055] Also, 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, by disconnecting the motor shaft 42 of the upper motor 41 from the motor shaft 22 of the lower motor 21, compared with the case where the motor shaft 42 of the upper motor 41 is connected to the motor shaft 22 of the lower motor 21, 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.

[0056] In addition, in the outboard motor 1 of this embodiment, 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 is connected to the motor shaft 22 of the lower motor 21. The power switching device 61 is arranged between the lower motor 21 and the upper motor 41. Due to providing two motors 21, 41 and the power switching device 61 in the outboard motor, it is possible to prevent the outboard motor from becoming significantly larger. Specifically, by arranging the lower motor 21 and the upper motor 41 side by side in the vertical direction such that their respective motor shafts 22, 42 extend in the vertical direction, 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 brought closer to each other within the space between the lower motor 21 and the upper motor 41. Then, by arranging the power switching device 61 between the lower motor 21 and the upper motor 41 and configuring the power switching device 61 to connect the upper end portion of the motor shaft 22 and the lower end portion of the motor shaft 42, which are arranged close to each other within the space between the lower motor 21 and the upper motor 41, so as to be disconnectable from each other, the power switching device 61 can be formed compactly. That is, since the upper end portion of the motor shaft 22 and the lower end portion of the motor shaft 42 of the upper motor 41 are close to each other, the means for connecting the upper end portion of the motor shaft 22 and the lower end portion of the motor shaft 42 can be formed by a connecting shaft 62, which is a short shaft arranged between the upper end portion of the motor shaft 22 and the lower end portion of the motor shaft 42. Also, by arranging a switching mechanism 71 for moving the connecting shaft 62 between the lower motor 21 and the upper motor 41, the connecting shaft 62 and the switching mechanism 71 can be concentrated and arranged between the lower motor 21 and the upper motor 41.

[0057] According to the outboard motor 1 of this embodiment, it is possible to prevent the upper part of the outboard motor 1 from being significantly enlarged, 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 switching 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.

[0058] Also, in the outboard motor 1 of this embodiment, the power switching device 61 includes a connecting shaft 62 that is provided between the lower motor 21 and the upper motor 41 so as to be movable in the vertical direction. When the connecting shaft 62 moves downward, it connects 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 to each other, and when it moves upward, it disconnects 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 from each other. With this configuration, the connection and disconnection between the motor shaft 22 and the motor shaft 42 can be realized with a simple configuration, and the power switching device 61 can be formed compactly.

[0059] In addition, in the outboard motor 1 of the present embodiment, the motor shaft 22 of the lower motor 21 and the motor shaft 42 of the upper motor 41 are arranged coaxially with each other. The connecting shaft 62 is provided coaxially with the motor shafts 22 and 42 and movably in the vertical direction between 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. At the upper end of the connecting shaft 62, a connecting portion 63 is provided to connect the connecting shaft 62 to the lower end of the motor shaft 42 of the upper motor 41 so that the connecting shaft 62 is non-rotatable relative to the motor shaft 42 of the upper motor 41 and is movable in the vertical direction relative to the motor shaft 42. At the lower end of the connecting shaft 62, a fitting portion 65 is provided to fit with the fitted portion 34 provided at the upper end of the motor shaft 22 of the lower motor 21. When the connecting shaft 62 moves downward, the fitting portion 65 fits with the fitted portion 34 while the connecting portion 63 remains connected to the lower end of the motor shaft 42 of the upper motor 41, thereby connecting 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 to each other. When the connecting shaft 62 moves upward, 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 are disconnected from each other by releasing the fit between the fitting portion 65 and the fitted portion 34. With this configuration, a mechanism for disconnectably connecting the motor shaft 22 and the motor shaft 42 to each other can be constituted by a single short connecting shaft 62 that is movable in the vertical direction. Therefore, the mechanism for disconnectably connecting the motor shaft 22 and the motor shaft 42 to each other can be simplified, the number of parts related to the mechanism can be reduced, and the weight of the mechanism can be reduced. In addition, although the motor shaft 22 and the motor shaft 42 can be disconnected from each other, the two shafts can be firmly connected to each other. Therefore, when the motor shaft 22 and the motor shaft 42 are connected to each other, the transmission of the power of the upper motor 41 to the drive shaft 4 can be stabilized.

[0060] Further, according to the outboard motor 1 of the present embodiment, the motor shaft 22 of the lower motor 21 and the motor shaft 42 of the upper motor 41 are connected to each other by the connecting shaft 62 without using a gear (spur gear). As a result, without considering the configuration of the gear (for example, gear ratio, etc.), the rotational speeds of the lower motor 21 and the upper motor 41 can be easily made to match, and a configuration for inputting both the power of the lower motor 21 and the power of the upper motor 41 to the drive shaft 4 can be easily formed.

[0061] In addition, in the power switching device of the power unit 2 of the outboard motor 1, the structure in which the motor shaft 22 of the lower motor 21 and the motor shaft 42 of the upper motor 41 are connected by a connecting shaft so as to be disconnectable can be reversed up and down. That is, like the power switching device 101 shown in FIG. 10, a connecting shaft coupling hole 91 is provided on the upper end surface of the motor shaft 22 of the lower motor 21, a coupling portion 103 is provided at the lower end portion of the connecting shaft 102, and the coupling portion 103 is inserted into the connecting shaft coupling hole 91, and the connecting shaft 102 and the motor shaft 22 of the lower motor 21 are coupled so that the connecting shaft 102 is non-rotatable with respect to the motor shaft 22 of the lower motor 21 and is movable in the vertical direction with respect to the motor shaft 22. Further, a connecting shaft insertion hole 92 is provided on the lower end surface of the motor shaft 42 of the upper motor 41, and the upper end portion 104 of the connecting shaft 102 is inserted into the connecting shaft insertion hole 92 so that the upper end portion 104 of the connecting shaft 102 does not contact the inner peripheral surface of the connecting shaft insertion hole 92. Further, a fitted portion 93 is provided on the outer peripheral portion of the lower end surface of the motor shaft 42 of the upper motor 41, and a fitting portion 105 that fits with the fitted portion 93 is provided on the upper portion of the connecting shaft 102. Further, a lower flange portion 106 and an upper flange portion 107 are provided at the intermediate portion in the vertical direction of the connecting shaft 102, and the fork 80 of the fork unit 78 in the switching mechanism 71 is inserted into the fork insertion portion 108 between the lower flange portion 106 and the upper flange portion 107. In the power switching device 101, when the connecting shaft 102 moves upward, the fitting portion 105 fits with the fitted portion 93 while maintaining the state in which the coupling portion 103 is coupled to the upper end portion of the motor shaft 22 of the lower motor 21. Thereby, 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 connected to each other. On the other hand, when the connecting shaft 102 moves downward, the fitting between the fitting portion 105 and the fitted portion 93 is released. Thereby, 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 disconnected from each other.

[0062] Further, in the above-described embodiment, the lower motor 21 and the upper motor 41, which have 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.

[0063] Moreover, 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 units other than outboard motors.

[0064] In addition, the present invention can be appropriately modified within a range 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 unit with such modifications is also included in the technical idea of the present invention.

Explanation of Reference Numerals

[0065] 1 Outboard motor (marine propulsion unit) 2 Power unit 3 Propeller 4 Drive shaft 21 Lower motor (first motor) 22 Motor shaft (first motor shaft) 33, 92 Connecting shaft insertion hole 34, 93 Fitted portion 41 Upper motor (second motor) 42 Motor shaft (second motor shaft) 53, 91 Connecting shaft coupling hole 61, 101 Power switching device 62, 102 Connecting shaft (connecting member) 63, 103 Coupling portion 65, 105 Fitting portion 71 Switching mechanism

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 switching device that connectably connects the first motor shaft and the second motor shaft to each other and switches between a state in which the first motor shaft and the second motor shaft are connected to each other and a state in which the first motor shaft and the second motor shaft are disconnected from each other, wherein the first motor and the second motor are disposed above 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 an upper portion of the drive shaft is connected to the first motor shaft, and wherein the power switching 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 switching device includes a connecting member movably provided in the vertical direction between the first motor and the second motor, and the connecting member connects the upper end portion of the first motor shaft and the lower end portion of the second motor shaft to each other when moving in one direction in the vertical direction, and disconnects the upper end portion of the first motor shaft and the lower end portion of the second motor shaft from each other when moving in the other direction in the vertical direction.

3. The first motor shaft and the second motor shaft are coaxially arranged with respect to each other, the connecting member is a shaft provided coaxially with the first motor shaft and the second motor shaft and movably in the vertical direction between the upper end portion of the first motor shaft and the lower end portion of the second motor shaft, a coupling portion for coupling the connecting member to the lower end portion of the second motor shaft is provided at the upper end portion of the connecting member so that the connecting member is non-rotatable with respect to the second motor shaft and is movable in the vertical direction with respect to the second motor shaft, and a fitting portion for fitting with a fitting portion provided at the upper end portion of the first motor shaft is provided at the lower end portion of the connecting member. When the connecting member moves downward, the fitting portion fits with the fitted portion while maintaining the state where the coupling portion is coupled to the lower end portion of the second motor shaft, thereby connecting the upper end portion of the first motor shaft and the lower end portion of the second motor shaft to each other. When the connecting member moves upward, the upper end portion of the first motor shaft and the lower end portion of the second motor shaft are disconnected from each other by releasing the fit between the fitting portion and the fitted portion. The marine propulsion device according to claim 2, characterized in that.

4. The first motor shaft and the second motor shaft are arranged coaxially with each other. The connecting member is a shaft provided coaxially with the first motor shaft and the second motor shaft and movable in the vertical direction between the upper end portion of the first motor shaft and the lower end portion of the second motor shaft. A coupling portion is provided at the lower end portion of the connecting member for coupling the connecting member to the upper end portion of the first motor shaft so that the connecting member is non-rotatable with respect to the first motor shaft and movable in the vertical direction with respect to the first motor shaft. A fitting portion is provided at the upper end portion of the connecting member for fitting with a fitted portion provided at the lower end portion of the second motor shaft. When the connecting member moves upward, the fitting portion fits with the fitted portion while maintaining the state where the coupling portion is coupled to the upper end portion of the first motor shaft, thereby connecting the upper end portion of the first motor shaft and the lower end portion of the second motor shaft to each other. When the connecting member moves downward, the upper end portion of the first motor shaft and the lower end portion of the second motor shaft are disconnected from each other by releasing the fit between the fitting portion and the fitted portion. The marine propulsion device according to claim 2, characterized in that.

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