SHIP PROPULSION MACHINE

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2023-194303 filed on Nov. 15, 2023, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a ship propulsion machine using a motor (electric motor) as a power source for generating a propulsive force of a ship.

BACKGROUND ART

In an outboard motor, a motor is provided in a part located below a water surface in a state in which the outboard motor is attached to a hull, i.e., a lower part of the outboard motor, and a propeller is attached to a rear end portion of a shaft extending rearward from the motor. This type of outboard motor has the motor arranged in the lower part of the outboard motor. Therefore, when a large motor is adopted, the lower part of the outboard motor becomes larger, which may increase water resistance during sailing. This makes it difficult to adopt a large motor for this type of outboard motor.

JP2005-153727A describes an outboard motor in which a motor is provided in a part located above a water surface in a state in which the outboard motor is attached to a hull, i.e., an upper part of the outboard motor. This type of outboard motor includes a drive shaft extending vertically between the motor and a propeller shaft provided at a lower part of the outboard motor, and is configured to transmit an output of the motor to the propeller shaft by the drive shaft. In this type of outboard motor, the motor is provided in the upper part of the outboard motor. Therefore, even when a large motor is adopted, the size of the lower part of the outboard motor can be suppressed from increasing. This makes it easy to adopt a large motor.

SUMMARY OF INVENTION

In a ship propulsion machine that uses a motor as a power source for generating a propulsive force of a ship, when the motor fails during sailing, it becomes difficult to move the ship.

In this regard, a method is considered in which the ship propulsion machine is provided with two motors, and when one motor fails, the ship is moved with the other motor. This method can be implemented, for example, by providing a ship propulsion machine with a first motor, a second motor, and a power transmission mechanism, and causing the power transmission mechanism to switch between a state in which an output of the first motor is transmitted to a propeller and a state in which an output of the second motor is transmitted to the propeller.

However, when the ship propulsion machine is provided with the first motor, the second motor, and the power transmission mechanism, there is a concern that the ship propulsion machine will become significantly larger compared to a ship propulsion machine in which only one motor is provided as a power source for generating a propulsive force of a ship. For example, if the first motor, the second motor, and the power transmission mechanism are provided in the lower part of the outboard motor, the lower part of the outboard motor becomes significantly larger, which may increase the water resistance during sailing. In addition, even if the first motor, the second motor, and the power transmission mechanism are provided in the upper part of the outboard motor, the upper part of the outboard motor becomes significantly larger, which may increase air resistance during sailing, reduce the attachment stability of the outboard motor to the hull, or deteriorate the appearance of the outboard motor.

The present disclosure has been made in view of the problems described above, for example, and an object of the present disclosure is to provide a ship propulsion machine that can reduce the possibility that movement of a ship will become difficult in the event that a motor that generates a propulsive force of the ship fails during sailing, while also preventing the ship propulsion machine from becoming significantly larger.

The present disclosure provides a ship propulsion machine including: a power unit configured to generate power; a propeller; and a drive shaft configured to transmit the power generated by the power unit to the propeller. The power unit includes: a first motor including a first motor shaft; a second motor including a second motor shaft; and a power transmission device configured to transmit at least one of a first power output from the first motor shaft and a second power output from the second motor shaft to the drive shaft, and switch power to be transmitted to the drive shaft such that at least one of the first power and the second power is selected. The first motor and the second motor are arranged in an upper part of the ship propulsion machine. Each of the first motor shaft, the second motor shaft, and the drive shaft extends vertically. The second motor is arranged above the first motor. An upper portion of the drive shaft passes through the first motor shaft so as to be rotatable independently of the first motor shaft and reaches a region between the first motor and the second motor. The power transmission device is arranged between the first motor and the second motor.

According to the present disclosure, it is possible to reduce the possibility that movement of a ship will become difficult in the event that a motor that generates a propulsive force of the ship fails during sailing, while also preventing the ship propulsion machine from becoming significantly larger.

BRIEF DESCRIPTION OF DRAWINGS

The present disclosure will be described in detail based on the following without being limited thereto, wherein:

FIG. 1 is an overall view showing an outboard motor according to an embodiment of the present disclosure;

FIG. 2 is an external perspective view showing a power unit and the like in the outboard motor according to the embodiment of the present disclosure;

FIG. 3 is an external view showing the power unit and the like in FIG. 2, as viewed from the left.

FIG. 4 is an external view showing the power unit and the like in FIG. 2, as viewed from the front;

FIG. 5 is a cross-sectional view taken along cutting line V-V in FIG. 4, showing the power unit as viewed from the left;

FIG. 6 is a cross-sectional view taken along cutting line VI-VI in FIG. 3, showing a power transmission device and the like, as viewed from above;

FIG. 7 is an explanatory view showing a space between a lower motor and an upper motor in the power unit of the outboard motor according to the embodiment of the present disclosure, as viewed from the left;

FIG. 8 is an explanatory view showing a dog clutch, a lower fitted member, and a motor shaft of the lower motor in the power unit of the outboard motor according to the embodiment of the present disclosure;

FIGS. 9A to 9C are explanatory views showing operations of the power transmission device in the power unit of the outboard motor according to the embodiment of the present disclosure; and

FIG. 10 is an exploded perspective view showing a switching mechanism in the power transmission device of the power unit of the outboard motor according to the embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

A ship propulsion machine according to an embodiment of the present disclosure includes a power unit that generates power, a propeller, and a drive shaft that transmits 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.

In the ship propulsion machine according to 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 at least one of first power output from the first motor shaft and second power output from the second motor shaft to the drive shaft. Additionally, the power transmission device switches the power, which is transmitted to the drive shaft, such that at least one of the first power and the second power is selected.

In the ship propulsion machine according to the present embodiment, the first motor and the second motor are arranged in an upper part of the ship propulsion machine. Additionally, the first motor shaft, the second motor shaft, and the drive shaft each extend vertically. Additionally, the second motor is arranged above the first motor. Additionally, an upper portion of the drive shaft passes through the first motor shaft and reaches a region between the first motor and the second motor. Additionally, the drive shaft can rotate independently of the first motor shaft. For example, the first motor shaft is formed in a cylindrical shape having an inner diameter larger than an outer diameter of the drive shaft, and the upper portion of the drive shaft is inserted into an inner periphery side of the first motor shaft in a state where it is spaced apart from an inner peripheral surface of the first motor shaft. In addition, the power transmission device is arranged between the first motor and the second motor.

According to the ship propulsion machine of the present embodiment, it is possible to reduce the possibility that movement of a ship will become difficult in the event that a motor that generates a propulsive force of the ship fails during sailing. Specifically, the power that is transmitted to the drive shaft can be switched such that at least one of the first power from the first motor and the second power from the second motor is selected. Therefore, when the first motor fails, the ship can be moved by the second motor. In addition, when the second motor fails, the ship can be moved by the first motor.

In addition, according to the ship propulsion machine of the present embodiment, the first motor, the second motor, and the power transmission device are provided in the ship propulsion machine, which can prevent the ship propulsion machine from becoming significantly larger. Specifically, the first motor and the second motor are arranged vertically side by side such that each motor shaft thereof extends vertically, and the power transmission device is arranged between the first motor and the second motor, allowing the power transmission device to be made compact. As a result, the extent of enlargement of the ship propulsion machine can be reduced compared to a ship propulsion machine having only one motor.

The fact that the power transmission device can be made compact is specifically described. In the upper part of the ship propulsion machine of the present embodiment, the first motor and the second motor are arranged such that each of the first motor shaft and the second motor shaft extends vertically. Additionally, the second motor is arranged above the first motor. With this arrangement, an upper end portion of the first motor shaft and a lower end portion of the second motor shaft can be brought close to each other within the space (region) between the first motor and the second motor. Additionally, an upper portion of the drive shaft passes through the first motor shaft and reaches between the first motor and the second motor. This makes it possible to bring an upper end portion of the drive shaft close to the upper end portion of the first motor shaft and the lower end portion of the second motor shaft, respectively, 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. In addition, 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 so as to be close to each other within the space between the first motor and the second motor, the power transmission device that selectively connects at least one of the upper end portion of the first motor shaft and the lower end portion of the second motor shaft to the upper end portion of the drive shaft can be made compact.

Hereinafter, a case in which the present disclosure is applied to an outboard motor, which is a type of ship propulsion machine, will be described as an embodiment of the present disclosure. In the description of the present embodiment, when referring to upper (Ud), lower (Dd), front (Fd), rear (Bd), left (Ld), and right (Rd) directions, they follow arrows drawn at the lower right in each drawing.

(Outboard Motor)

FIG. 1 shows an outboard motor 1 according to an embodiment of the present disclosure. 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.

The power unit 2 generates power to propel a ship. The power unit 2 is arranged in an upper part of the outboard motor 1 so that it is positioned above a water surface in a state in which the outboard motor 1 is attached to the ship. Additionally, the power unit 2 is fixed to a motor holder 9 provided in the upper part of the outboard motor 1.

The propeller 3 converts the power generated by the power unit 2 into a propulsive force. The propeller 3 is arranged at a lower part of the outboard motor 1 so that it is positioned below the water surface in a state in which the outboard motor 1 is attached to the ship.

The drive shaft 4, the propeller shaft 5, and the gear mechanism 6 transmit the power generated by 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. An upper portion of the drive shaft 4 is introduced inside the power unit 2. The propeller shaft 5 is arranged in the lower part of the outboard motor 1 and extends in the front-rear direction. The propeller 3 is fixed to a rear portion of the propeller shaft 5. The gear mechanism 6 is arranged at a front side part in 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 being fixed to a lower end portion of the drive shaft 4 and the driven gear 8 being fixed to a front end portion of the propeller shaft 5. Both the drive gear 7 and the driven gear 8 are bevel gears, and the meshing of these gears converts rotation of the drive shaft 4 around a vertical axis into rotation of the propeller shaft 5 around a horizontal axis. The drive shaft 4 rotates by receiving the power from the power unit 2, and the rotation of the drive shaft 4 is transmitted to the propeller shaft 5 via the gear mechanism 6, thereby rotating the propeller 3 together with the propeller shaft 5.

Additionally, the upper part of the outboard motor 1 is provided with a motor cover 10 that covers the power unit 2 and the motor holder 9. The motor cover 10 is divided into a bottom cover 11 that covers a lower part of the power unit 2 and the motor holder 9, and a top cover 12 that covers an upper part of the power unit 2. In addition, a vertically middle part of the outboard motor 1 is provided with a drive shaft case 13 that covers an outer periphery side of the drive shaft 4. Additionally, the lower part of the outboard motor 1 is provided with a gear case 14 that covers a front side part of the gear mechanism 6 and the propeller shaft 5. Additionally, the outboard motor 1 is provided with a clamp mechanism 15 for detachably fixing the outboard motor 1 to a ship hull.

(Power Unit)

FIG. 2 shows the power unit 2 and the motor holder 9 as viewed from the upper left front. FIG. 3 shows the power unit 2 and motor holder 9 as viewed from the left. FIG. 4 shows the power unit 2 and the motor holder 9 as viewed from the front. FIG. 5 is a cross-sectional view of the power unit 2 taken along cutting line V-V in FIG. 4, as viewed from the left (right in FIG. 4).

As shown in FIG. 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.

The lower motor 21 is an AC electric motor, i.e., an AC motor. As shown in FIG. 5, the lower motor 21 includes a motor shaft 22, a rotor 23 provided on an outer periphery side of the motor shaft 22, a stator 24 provided on an outer periphery side of the rotor 23, and a cylindrical motor case 25 provided on an outer periphery 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. Additionally, the motor shaft 22 is formed in a cylindrical shape. In other words, a central portion of the motor shaft 22 is formed with a through-hole penetrating axially.

Additionally, the lower motor 21 includes a bottom motor bracket 26 and a top motor bracket 27, as shown in FIG. 2. The bottom motor bracket 26 is formed in a polygonal or circular plate shape and is arranged below the motor case 25 so as to substantially block a 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, the lower part of the motor case 25 is provided with a plurality of motor fixing portions 25A protruding outward, and these motor fixing portions 25A are fixed to the bottom motor bracket 26. In addition, as shown in FIG. 5, a central portion of the bottom motor bracket 26 is formed with a motor shaft insertion hole 26A. A lower end portion of the motor shaft 22 is rotatably supported by a bearing 31 inside the motor shaft insertion hole 26A. In addition, as shown in FIG. 3, the bottom motor bracket 26 is provided on an upper surface of a front side part of the motor holder 9 and is fixed to the motor holder 9.

As shown in FIG. 2, the top motor bracket 27 is formed in a polygonal or circular plate shape and is arranged above the motor case 25 so as to substantially block an 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, the upper part of the motor case 25 is provided with a plurality of motor fixing portions 25B protruding outward, and these motor fixing portions 25B are fixed to the top motor bracket 27. In addition, a central portion of the top motor bracket 27 is formed with a motor shaft insertion hole 27A, as shown in FIG. 5. An upper end portion of the motor shaft 22 is rotatably supported by a bearing 32 inside the motor shaft insertion hole 27A.

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

The upper motor 41 is an AC motor. In the present 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 similarly to the lower motor 21. First of all, the motor shaft 42 of the upper motor 41, unlike the motor shaft 22 of the lower motor 21, is not cylindrical. That is, the motor shaft 42 is not formed with a through-hole penetrating axially through a central portion thereof. Note that for the purpose of reducing the weight of the motor shaft 42, and the like, the motor shaft 42 may be formed into a cylindrical shape.

Additionally, 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 arranged below the motor case 45 so as to substantially block a lower part of the motor case 45. The lower part of the motor case 45 is fixed to the bottom motor bracket 46 via, for example, a plurality of motor fixing portions 45A protruding outward from the lower part of the motor case 45. Additionally, a central portion of the bottom motor bracket 46 is formed with a motor shaft insertion hole 46A. A lower end portion of the motor shaft 42 is rotatably supported by a bearing 51 inside the motor shaft insertion hole 46A.

The top motor bracket 49 is formed in a polygonal or circular plate shape and is arranged above the motor case 45 so as to substantially block an upper part of the motor case 45. The upper part of the motor case 45 is fixed to the top motor bracket 49 via, for example, a plurality of motor fixing portions 45B protruding outward from the upper part of the motor case 45. Additionally, a central portion of the top motor bracket 49 is formed with a motor shaft insertion hole 49A. An upper end portion of the motor shaft 42 is rotatably supported by a bearing 52 inside the motor shaft insertion hole 49A.

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

The upper motor 41 is arranged above the lower motor 21. The lower motor 21 and the upper motor 41 are arranged so that the motor shafts 22 and 42 extend vertically, respectively. The lower motor 21 and the upper motor 41 are arranged so that the motor shafts 22 and 42 are coaxial.

The lower motor 21 and the upper motor 41 are connected to each other using a plurality of support members 85, as shown in FIGS. 2 to 5. Each support member 85 is formed of, for example, a metal material and extends vertically. Each support member 85 is arranged between the top motor bracket 27 of the lower motor 21 and the bottom motor bracket 46 of the upper motor 41. A lower part of each support member 85 is fixed to the top motor bracket 27 of the lower motor 21, and an upper part of each support member 85 is fixed to the bottom motor bracket 46 of the upper motor 41. In the present embodiment, a central portion of each support member 85 is formed with a through-hole penetrating axially. In addition, through-holes penetrating vertically 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 arranged. 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 onto an end portion of the bolt 86. With this, the lower motor 21 and the upper motor 41 are connected.

The plurality of support members 85 are arranged on an outer periphery side portion of each of the top motor bracket 27 and the bottom motor bracket 46. FIG. 6 is a cross-sectional view of the power unit 2 taken along cutting line VI-VI in FIG. 3, as viewed from above. As shown in FIG. 6, in the present embodiment, two of the seven support members 85 are arranged on the left side portion of the top motor bracket 27 and the bottom motor bracket 46, the other two support members 85 are arranged on the right side portion of the top motor bracket 27 and the bottom motor bracket 46, and the remaining three support members 85 are arranged on the rear portion of the top motor bracket 27 and the bottom motor bracket 46.

A space is formed between the lower motor 21 and the upper motor 41 by the plurality of support members 85. In the space between the lower motor 21 and the upper motor 41, as shown in FIG. 5, 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 to be close to each other.

Additionally, the upper portion of the drive shaft 4 is inserted into the inner periphery 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 periphery 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. 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.

Additionally, an inner diameter of the motor shaft 22 of the lower motor 21 is set to a larger value than an 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 in which an outer peripheral surface thereof is spaced apart from an 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.

Note that the lower motor 21 is a specific example of a “first motor”, and the motor shaft 22 of the lower motor 21 is a specific example of a “first motor shaft”. Additionally, the upper motor 41 is a specific example of a “second motor,” and the motor shaft 42 of the upper motor 41 is a specific example of a “second motor shaft.”

(Power Transmission Device)

The power unit 2 includes a power transmission device 61 that transmits one or both of the power of the lower motor 21, i.e., the power output from the motor shaft 22 of the lower motor 21 and the power of the upper motor 41, i.e., 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, which is transmitted to the drive shaft 4, so as to be selectable from among (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.

FIG. 7 shows the space between 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 arranged between the lower motor 21 and the upper motor 41. The power transmission device 61 includes a dog clutch 62, a lower fitted member 66, an upper fitted member 68, and a switching mechanism 71.

FIG. 8 shows the dog clutch 62, the lower fitted 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. In addition, as shown in FIG. 5, the dog clutch 62 is attached to the outer periphery 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 vertically with respect to the drive shaft 4.

As shown in FIG. 8, an upper portion of the dog clutch 62 is formed with an upper fitting portion 64. An outer periphery side of the upper fitting portion 64 is formed with an unevenness. Additionally, a lower portion of the dog clutch 62 is formed with a lower fitting portion 63. An outer periphery side of the lower fitting portion 63 is formed with an unevenness similar to that formed on the outer periphery side of the upper fitting portion 64. Additionally, an outer peripheral surface of a vertically middle portion of the dog clutch 62 is formed with a clutch groove 65. The clutch groove 65 extends over an entire periphery of the dog clutch 62.

The lower fitted member 66 is formed in a cylindrical shape. In addition, as shown in FIG. 5, the lower fitted member 66 is fixed to the upper end portion of the motor shaft 22 of the lower motor 21 so as to be non-rotatable with respect to the motor shaft 22. Specifically, the upper end portion of the motor shaft 22 of the lower motor 21 is formed with a fitted member insertion portion 22A where the inner diameter of the motor shaft 22 is made larger than the inner diameter of the other portion of the motor shaft 22. A lower portion of the lower fitted member 66 is inserted into the fitted member insertion portion 22A and is fixed inside the fitted member insertion portion 22A by a method such as spline coupling.

As shown in FIG. 8, an upper portion of the lower fitted member 66 is formed with a fitted portion 67. An inner periphery side of the fitted portion 67 is formed with an unevenness. A shape of the unevenness of the lower fitting portion 63 of the dog clutch 62 and a shape of the unevenness of the fitted portion 67 of the lower fitted member 66 are set so that the lower fitting portion 63 can be fitted with the fitted portion 67.

The upper fitted member 68 is formed in a cylindrical shape, and as shown in FIG. 5, is fixed to the lower end portion of the motor shaft 42 of the upper motor 41 so as to be non-rotatable with respect to the motor shaft 42. Specifically, the lower end portion of the motor shaft 42 of the upper motor 41 is formed with a fitted member insertion portion 42A. The fitted member insertion portion 42A is a hole formed at a central portion of a lower end surface of the motor shaft 42. An upper portion of the upper fitted member 68 is inserted into the fitted member insertion portion 42A and is fixed inside the fitted member insertion portion 42A by a method such as spline coupling.

A lower portion of the upper fitted member 68 is formed with a fitted portion 69 (see FIG. 9A). An inner periphery side of the fitted portion 69 is formed with an unevenness. A shape of the unevenness of the upper fitting portion 64 of the dog clutch 62 and a shape of the unevenness of the fitted portion 69 of the upper fitted member 68 are set so that the upper fitting portion 64 can be fitted with the fitted portion 69.

Note that two common fitted members may be used as the lower fitted member 66 and the upper fitted member 68. That is, one of the two common fitted members may be used as the lower fitted member 66 by fixing the one fitted member within the fitted member insertion portion 22A of the motor shaft 22 of the lower motor 21 so that the fitted member faces upward, and the other of the two common fitted members may be used as the upper fitted member 68 by fixing the other fitted member within the fitted member insertion portion 42A of the motor shaft 42 of the upper motor 41 so that the fitted member faces downward.

In addition, the lower fitting portion 63 of the dog clutch 62 is a specific example of a “first fitting portion,” and the upper fitting portion 64 of the dog clutch 62 is a specific example of a “second fitting portion.” In addition, the fitted portion 67 of the lower fitted member 66 is a specific example of a “first fitted portion,” and the fitted portion 69 of the upper fitted member 68 is a specific example of a “second fitted portion.”

FIGS. 9A to 9C show operations of the power transmission device 61. The dog clutch 62 is not rotatable with respect to the drive shaft 4, but can move vertically within a predetermined movement range with respect to the drive shaft 4. In the present embodiment, the dog clutch 62 can move vertically within a movement range from a position where the lower fitting portion 63 of the dog clutch 62 is deeply fitted with the fitted portion 67 of the lower fitted member 66, as shown in FIG. 9B, to a position where the upper fitting portion 64 of the dog clutch 62 is deeply fitted with the fitted portion 69 of the upper fitted member 68, as shown in FIG. 9C.

As shown in FIG. 9A, when the dog clutch 62 moves to a middle position within the movement range, the lower fitting portion 63 of the dog clutch 62 is fitted with the fitted portion 67 of the lower fitted member 66, and the upper fitting portion 64 of the dog clutch 62 is fitted with the fitted portion 69 of the upper fitted member 68. With this, the motor shaft 22 of the lower motor 21 and the drive shaft 4 are interconnected 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 interconnected via the dog clutch 62. As a result, both the power of the lower motor 21 and the power of the upper motor 41 are transmitted to the drive shaft 4, the drive shaft 4 is rotated by the powers of both the lower motor 21 and the upper motor 41, and the propeller 3 is rotated by the powers of both the lower motor 21 and the upper motor 41.

As shown in FIG. 9B, when the dog clutch 62 moves to a lower position within the movement range, the lower fitting portion 63 of the dog clutch 62 is fitted with the fitted portion 67 of the lower fitted member 66, and the fitting between the upper fitting portion 64 of the dog clutch 62 and the fitted portion 69 of the upper fitted member 68 is released. With this, the motor shaft 22 of the lower motor 21 and the drive shaft 4 are interconnected 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, only the power of the lower motor 21 of the two motors of the power unit 2 is transmitted to the drive shaft 4, the drive shaft 4 is rotated only by the power of the lower motor 21, and the propeller 3 is rotated only by the power of the lower motor 21.

As shown in FIG. 9C, when the dog clutch 62 moves to an upper portion within the movement range, the upper fitting portion 64 of the dog clutch 62 is fitted with the fitted portion 69 of the upper fitted member 68, and the fitting between the lower fitting portion 63 of the dog clutch 62 and the fitted portion 67 of the lower fitted member 66 is released. With this, the motor shaft 42 of the lower motor 41 and the drive shaft 4 are interconnected via the dog clutch 62, and at the same time, the motor shaft 22 of the upper motor 21 and the drive shaft 4 are disconnected. As a result, only the power of the upper motor 41 of the two motors of the power unit 2 is transmitted to the drive shaft 4, the drive shaft 4 is rotated only by the power of the upper motor 41, and the propeller 3 is rotated only by the power of the upper motor 41.

(Switching Mechanism)

The power transmission device 61 includes a switching mechanism 71 that switches power, which is transmitted to the drive shaft 4, so as to be selectable from among (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 operation input from the outside. FIG. 10 is an exploded view showing components of the switching mechanism 71. 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 camshaft 76, and a fork unit 78.

One end portion of the first joint member 73 is connected to the clutch rod 72 so as to be non-rotatable with respect to the clutch rod 72. One end portion of the clutch link 74 is connected to the other end portion of the first joint member 73 so as to be rotatable with respect to the first joint member 73. One end portion of the second joint member 75 is connected to the other end of the clutch link 74 so as to be non-rotatable with respect to the clutch link 74. The other end portion of the second joint member 75 is connected to an upper portion of the clutch camshaft 76 so as to be non-rotatable with respect to the clutch camshaft 76. The clutch camshaft 76 has a cylindrical cam structure, and a cam groove 77 is formed on an outer peripheral surface of a vertically middle portion of the clutch camshaft 76. The vertically middle portion of the clutch camshaft 76 is inserted into the inner periphery side of a tubular portion 79 of the fork unit 78. A driven pin 81 is inserted into a pin hole 79A formed in the tubular portion 79 of the fork unit 78. The driven pin 81 passes through the pin hole 79A, and a tip end portion of the driven pin 81 is inserted into the cam groove 77 within the tubular portion 79. The driven pin 81 inserted in the pin hole 79A is locked to the tubular portion 79 of the fork unit 78 by a stopper member 83, with a coil spring 82 interposed. The tubular portion 79 of the fork unit 78 is formed with a fork 80. The fork 80 protrudes radially outward from the tubular portion 79. A tip end portion of the fork 80 is inserted into the clutch groove 65 of the dog clutch 62, as shown in FIGS. 5 to 7. The tip end portion of the fork 80 is inserted into the clutch groove 65 with a gap interposed so that the dog clutch 62 can rotate along with the rotation of the drive shaft 4 while the tip end portion of the fork 80 is inserted in the clutch groove 65.

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 is rotated in the direction of arrow C. The rotation of the clutch camshaft 76 moves the fork unit 78 upward, for example. The upward movement of the fork unit 78 moves the dog clutch 62 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 is rotated in the direction of arrow D. The rotation of the clutch camshaft 76 moves the fork unit 78 downward, for example. The downward movement of the fork unit 78 moves the dog clutch 62 downward. Note that the relationship between the rotation direction of the clutch rod 72 and the movement direction of the fork unit 78 in the vertical direction, and the relationship between the rotation amount of the clutch rod 72 and the movement amount of the fork unit 78 in the vertical direction can be set by the shape of the cam groove 77 formed on the clutch camshaft 76.

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

Although not shown, the upper part of the outboard motor 1 is provided with an actuator (e.g., a DC motor) for rotating the clutch rod 72, and an output shaft of the actuator is connected to the clutch rod 72. In addition, an operation input from the outside for moving the dog clutch 62 is input to the actuator. Based on the operation input from the outside, the actuator operates, the clutch rod 72 rotates, and the dog clutch 62 moves.

As described above, the outboard motor 1 according to the embodiment of the present disclosure includes the power unit 2 including the lower motor 21, the upper motor 41, and the power transmission device 61. The power transmission device 61 transmits one or both of the power of the lower motor 21 and the power of the upper motor 41 to the drive shaft 4, and can switch the power, which is transmitted to the drive shaft 4, so as to be selectable from among (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, the propulsive force of the ship can be generated by the power of the upper motor 41 by transmitting only the power of the upper motor 41 to the drive shaft 4, and the ship can be moved. In addition, when the upper motor 41 fails, the propulsive force of the ship can be generated by the power of the lower motor 21 by transmitting only the power of the lower motor 21 to the drive shaft 4, and the ship can be moved. Therefore, according to the outboard motor 1 of the embodiment of the present disclosure, it is possible to reduce the possibility that movement of a ship will become difficult in the event that a motor that generates a propulsive force of the ship fails during sailing.

In addition, according to the outboard motor 1 of the embodiment of the present disclosure, 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 in which 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 in which 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. In addition, by switching from the state in which both the power of the lower motor 21 and the power of the upper motor 41 are transmitted to the drive shaft 4 to the state in which 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.

In addition, according to the outboard motor 1 of the embodiment of the present disclosure, when applying regenerative braking by using the rotational force of the propeller 3 after stopping the motor drive, 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. With this, the internal resistance of the outboard motor 1, which reduces the rotational force of the propeller 3, can be reduced compared to a case where the motor shaft connected to the drive shaft 4 via the dog clutch 62 is both the motor shafts 22 and 42. Therefore, after stopping the motor drive, it is possible to sustain the rotation of the propeller 3 up to a low-speed range, thereby extending the time for which the regenerative braking can be used.

In addition, in the outboard motor 1 of the embodiment of the present disclosure, the lower motor 21 and the upper motor 41 are arranged in 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 vertically, the upper motor 41 is arranged above the lower motor 21, the upper portion of the drive shaft 4 passes through the motor shaft 22 so as to be rotatable independently of the motor shaft 22 of the lower motor 21 and reaches the space (region) between the lower motor 21 and the upper motor 41, and the power transmission device 61 is arranged between the lower motor 21 and the upper motor 41. With this configuration, the outboard motor 1 can be prevented from becoming significantly larger due to the lower motor 21, the upper motor 41, and the power transmission device 61 being provided in the outboard motor 1.

Specifically, the first motor 21 and the second motor 41 are arranged vertically side by side such that each of the motor shafts 22 and 42 extends vertically, allowing 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 to be brought close to each other within the space between the lower motor 21 and the upper motor 41. In addition, the drive shaft 4 is arranged so that its upper portion passes through the motor shaft 22 of the lower motor 21 and reaches the space between the lower motor 21 and the upper motor 41, allowing the upper portion of the drive shaft 4 to be brought close to the upper portion of the motor shaft 22 of the lower motor 21 and the lower portion of the motor shaft 42 of the upper motor 41, respectively, within the space between the lower motor 21 and the upper motor 41. In addition, the power transmission device 61 that switches the connection and disconnection of the upper end portion of the motor shaft 22, the lower end portion of the motor shaft 42, and the upper end portion of the drive shaft 4, which are positioned close to each other, is arranged between the lower motor 21 and the upper motor 41, allowing the power transmission device 61 to be made compact. That is, since the upper end portion of the motor shaft 22, the lower end portion of the motor shaft 42, and the upper end portion of the drive shaft 4 are positioned close to each other, the dog clutch 62 and the switching mechanism 71 can be miniaturized and collectively arranged.

According to the outboard motor 1 of the present embodiment, since the upper part of the outboard motor 1 can be prevented from becoming significantly larger, it is possible to suppress air resistance while sailing, prevent the reduction of attachment stability of the outboard motor 1 to the hull, and additionally, prevent the deterioration of the appearance of the outboard motor 1. In addition, in the outboard motor 1 of the present embodiment, the lower motor 21, the upper motor 41, and the power transmission device 61 are all arranged in the upper part of the outboard motor 1, so the lower part of the outboard motor 1 can be suppressed from becoming larger, and the water resistance during sailing of the ship can be prevented from increasing.

In addition, in the outboard motor 1 of the present 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, the lower fitted member 66 is fixed to the upper end portion of the motor shaft 22, the upper fitted 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 and the lower end portion of the motor shaft 42, and the upper end portion of the drive shaft 4 is provided with the dog clutch 62. With this configuration, the power transmission device 61 that selectively transmits the power of the lower motor 21 and/or the power of the upper motor 41 to the drive shaft 4 can be configured in a simple manner, so that the power transmission device 61 can be easily made.

In addition, in the outboard motor 1 of the present embodiment, the upper portion of the drive shaft 4 is configured to pass through the inner periphery side of the cylindrical motor shaft 22 of the lower motor 21 and reach the space between the lower motor 21 and the upper motor 41. With this configuration, the 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 made compact, allowing the power unit 2 to be miniaturized.

Note that, in the above embodiment, the power that is transmitted to the drive shaft 4 by the power transmission device 61 is switched so as to be selectable from among (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, but the present disclosure is not limited thereto. The power transmitted to the drive shaft 4 by the power transmission device may be switched only between (a) and (b), only between (a) and (c), or only between (b) and (c).

In addition, in the above embodiment, the lower motor 21 and the upper motor 41, which have the same performances in terms of power generation, such as output and torque, are provided in the power unit 2. However, the performances in terms of power generation, such as output and torque, may be made different between the lower motor 21 and the upper motor 41.

In addition, in the above embodiment, the case has been exemplified in which the upper portion of the motor shaft 22 is provided with the fitted portion that is fitted with the fitting portion of the dog clutch by fixing the lower fitted member 66 to the upper end portion of the motor shaft 22 of the lower motor 21. However, the present disclosure is not limited thereto. For example, the fitted portion that is fitted with the fitting portion of the dog clutch may be formed integrally with the upper end portion of the motor shaft 22. Similarly, for the motor shaft 42 of the upper motor 41, the fitted portion that is fitted with the fitting portion of the dog clutch may be formed integrally with the lower end portion of the motor shaft 42.

In addition, the type of motor that is used in the power unit in the present disclosure is not limited, and for example, a direct current motor may also be used. In addition, the present disclosure can be applied to a ship propulsion machine other than the outboard motor.

In addition, the present disclosure can be changed as appropriate without departing from the scope or spirit of the disclosure which can be read from the claims and the entire specification, and the ship propulsion machine to which such a change is applied is also included in the technical spirit of the present disclosure.

SHIP PROPULSION MACHINE

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CPC

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Priority Claims (1)