Power transmission device and marine vehicle engine system

Abstract

This power transmission device is configured to transmit the power of an engine installed in a marine vehicle traveling on water or underwater to a propeller of the marine vehicle, and comprises: an input shaft configured to receive the input of power from the engine; an output shaft configured to output the power to the propeller; and a magnetic gear rotary machine magnetically coupling the input shaft and the output shaft. The magnetic gear rotary machine includes: a magnet rotor connected to the input shaft; a magnetic pole piece rotor connected to the output shaft; a stator core circumferentially extending on the outside radially of the magnetic pole piece rotor; and a stator having a stator coil disposed in the stator core.

Description

Power transmission device and aircraft engine system

[0001] The present disclosure relates to a power transmission device for transmitting power from an engine installed in a vessel to a propeller of a vessel, and a vessel engine system. This application claims priority to Japanese Patent Application No. 2023-194171, filed with the Japan Patent Office on November 15, 2023, the contents of which are incorporated herein by reference.

[0002] The engine system disclosed in Patent Document 1 includes a power transmission device for transmitting power from an engine installed on a vessel to a propeller of the vessel. The power transmission device includes a reduction gear for reducing the rotation of the engine and outputting the reduced rotation to a propeller shaft.

[0003] Japanese Patent Application Laid-Open No. 2005-195053

[0004] The above reduction gear transmission includes a plurality of gears that mesh with each other, which may result in poor fuel economy for the engine and poor reliability for the power transmission device.

[0005] An object of the present disclosure is to provide a power transmission device and a watercraft engine system that improve reliability and engine fuel efficiency.

[0006] A power transmission device according to at least one embodiment of the present disclosure is configured to transmit power from an engine installed on a watercraft that travels at least one of on water and underwater to a propeller of the watercraft, and includes an input shaft configured to input the power from the engine, an output shaft configured to output the power to the propeller, and a magnetic gear rotating machine that magnetically couples the input shaft and the output shaft, wherein the magnetic gear rotating machine includes: a magnet rotor connected to the input shaft; a pole piece rotor connected to the output shaft; a stator having a stator core extending circumferentially radially outward of the pole piece rotor; and a stator coil arranged in the stator core.

[0007] An underwater vehicle engine system according to at least one embodiment of the present disclosure comprises the above-described power transmission device; the engine installed on the underwater vehicle; the propeller installed on the underwater vehicle; an electrical system electrically connected to the stator coil; and a control device for controlling the power transmission device, the engine, and the electrical system.

[0008] According to the present disclosure, it is possible to provide a power transmission device and a watercraft engine system that have improved reliability and engine fuel efficiency.

[0009] FIG. 1 is a schematic diagram of an underwater vehicle engine system according to one embodiment; FIG. 2 is a schematic diagram showing the internal structure of a magnetic gear rotating machine according to one embodiment; FIG. 3 is a schematic diagram of an electrical system and a control device according to one embodiment; FIG. 4 is a schematic diagram of a clutch control unit of a control device according to one embodiment; FIG. 5 is a schematic diagram of a control device for realizing engine start according to one embodiment; FIG. 6 is a schematic diagram showing changes in engine rotation speed over time at engine start; FIG. 7 is a flowchart showing engine start control processing according to one embodiment; FIG. 8 is a schematic diagram of a control device for realizing normal power generation according to one embodiment; FIG. 9 is a schematic diagram showing changes in propeller rotation speed over time during normal power generation according to one embodiment; FIG. 10 is a flowchart showing normal power generation control processing according to one embodiment; FIG. 11 is a schematic diagram of a control device for realizing regenerative power generation according to one embodiment; FIG. 12 is a schematic diagram showing changes in propeller rotation speed over time during regenerative power generation according to one embodiment; FIG. 13 is a flowchart showing regenerative power generation control processing according to one embodiment; FIG. 14 is a schematic diagram of a control device for realizing berthing power generation operation according to one embodiment; FIG. 15 is a flowchart showing control processing for berthing power generation according to one embodiment; FIG. 16 is a schematic diagram of a control device for realizing propeller rotation control operation according to one embodiment; FIG. 17 is a schematic diagram showing changes in propeller rotation speed over time when propeller rotation control according to one embodiment is executed; FIG. 18 is a flowchart showing propeller rotation control processing according to one embodiment.

[0010] Several embodiments of the present disclosure will be described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure and are merely illustrative examples. For example, expressions expressing relative or absolute arrangements, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such arrangements, but also express relative displacements with a tolerance or angle or distance to the extent that the same function is achieved. For example, expressions expressing the equality of things, such as "same," "equal," and "homogeneous," not only express strict equality, but also express tolerance or differences to the extent that the same function is achieved. For example, expressions expressing shapes such as a square or cylindrical shape not only express shapes such as a square or cylindrical shape in the strict geometric sense, but also express shapes including concave and convex portions, chamfered portions, etc., to the extent that the same effect is achieved. On the other hand, the expressions "comprise," "include," or "have" one component are not exclusive expressions that exclude the existence of other components. Note that similar components may be assigned the same reference numerals and descriptions thereof may be omitted.

[0011] <Overview of Vessel Engine System 1> FIG. 1 is a schematic diagram of a vehicle engine system 1 (hereinafter, sometimes simply referred to as engine system 1) according to one embodiment of the present disclosure. The engine system 1 includes an engine 3 installed in a vehicle such as a ship that travels on water or a submarine that travels both on water and underwater. The engine 3 is, for example, a four-stroke engine. The engine 3 includes a cylinder, a cylinder head with intake and exhaust valves, an injection unit that injects fuel into a combustion chamber surrounded by the cylinder and the cylinder head, a piston disposed in the cylinder, a crankshaft that rotates in conjunction with the piston, and an engine shaft 3a connected to the crankshaft. Note that the engine 3 may also be a two-stroke engine.

[0012] The engine system 1 incorporates a power transmission device 2 configured to transmit power from an engine 3 to a propeller 4 installed on a vessel. The power transmission device 2 includes an input shaft 7 configured to receive power from an engine shaft 3 a of the engine 3, an output shaft 8 configured to output power to a propeller shaft 4 a of the propeller 4, and a magnetic gear rotating machine 5 that magnetically couples the input shaft 7 and the output shaft 8.

[0013] The axes of the input shaft 7, the output shaft 8, and the magnetic gear rotating machine 5 are substantially aligned. In the following description, the axial direction of the above-mentioned axes may be simply referred to as the "axial direction." Furthermore, the circumferential direction and radial direction based on the axis may be simply referred to as the "radial direction" and the "axial direction," respectively. The "radially inner side" refers to the side approaching the axis, and the "radially outer side" refers to the side moving away from the axis.

[0014] 1 , the axial range in which the input shaft 7 is disposed and the axial range in which the output shaft 8 is disposed are separated from each other. The input shaft 7 is solid throughout its entire axial length. Similarly, the output shaft 8 is solid throughout its entire axial length. However, the present disclosure is not limited to this. For example, a configuration may be employed in which a portion of the input shaft 7 is inserted inside the output shaft 8 that is formed into a cylindrical shape (not shown).

[0015] The magnetic gear rotating machine 5 includes a magnet rotor 10 connected to the input shaft 7. The magnet rotor 10 has a rotor core 15 supported by the input shaft 7 and a plurality of magnets 19 supported by the rotor core 15. The rotor core 15 rotates integrally with the input shaft 7. The plurality of magnets 19 are arranged circumferentially on the rotor core 15. Each magnet 19 extends axially. The magnet rotor 10 illustrated in FIG. 1 employs a surface permanent magnet (SPM) configuration in which the plurality of magnets 19 are provided on the surface of the rotor core 15, but the present disclosure is not limited thereto. For example, an interior permanent magnet (IPM) configuration in which the plurality of magnets 19 are embedded in the rotor core 15 may also be employed (see FIG. 2).

[0016] 1 further includes a pole piece rotor 30 connected to the output shaft 8. The pole piece rotor 30 has a plurality of pole pieces 35 arranged in the circumferential direction. Each pole piece 35 is located radially outward of the magnet rotor 10 and extends in the axial direction. The pole pieces 35 are realized by a plurality of electromagnetic steel plates stacked in the axial direction, one or more powder magnetic cores extending in the axial direction, or a combination thereof.

[0017] The pole piece rotor 30 further has a first connecting portion 31 and a second connecting portion 32. The first connecting portion 31 connects one axial end of each pole piece 35 to the input shaft 7 via a bearing B1. The second connecting portion 32 connects the other axial end of each pole piece 35 to the output shaft 8. This allows the pole piece rotor 30 to rotate relative to the magnet rotor 10 and to rotate integrally with the output shaft 8.

[0018] 2, the detailed configuration of the pole piece rotor 30 is illustrated. The pole piece rotor 30 further includes a plurality of non-magnetic bodies 33. Each non-magnetic body 33 extends in the axial direction, and both ends thereof are connected to the first connecting portion 31 and the second connecting portion 32, respectively. The non-magnetic bodies 33 are formed of a material such as fiber reinforced plastic (FRP). The plurality of non-magnetic bodies 33 and the plurality of pole pieces 35 are arranged alternately in the circumferential direction, and each pole piece 35 and each non-magnetic body 33 radially faces the magnet rotor 10 with an inner air gap G1 between them.

[0019] The configuration of the pole piece rotor 30 is not limited to the example shown in FIG. 2 . The pole piece rotor 30 may further include an inner cover and an outer cover arranged to radially sandwich the pole pieces 35 and the non-magnetic material 33. Each of the inner cover and the outer cover is cylindrical and extends circumferentially. At least one of the pole pieces 35 may have a hole that is open in the axial direction, and this hole functions as a ventilation passage through which cooling air can pass. A similar hole may also be formed in at least one of the non-magnetic material 33. Furthermore, the non-magnetic material 33 may not be provided, in which case a gap is formed between two adjacent pole pieces 35.

[0020] Returning to Fig. 1 , the magnetic gear rotating machine 5 further includes a stator 20 disposed radially outward of the plurality of magnetic pole pieces 35. The stator 20 has a stator core 22 extending in the circumferential direction and a plurality of stator coils 27 disposed in the stator core 22. The stator coils 27 are electrically connected to an electric system 6, which is a component of the engine system 1. The transfer of power between the stator coils 27 and the electric system 6 is controlled by a control device 90 incorporated in the engine system 1. The control device 90 in this example is configured to control each of the power transmission device 2, the engine 3, and the electric system 6.

[0021] Referring to FIG. 2 , a detailed configuration of the stator 20 is illustrated. The stator 20 further includes a plurality of teeth 24 protruding radially inward from the stator core 22 and a plurality of stator magnets 29 arranged on the inner circumferential surfaces of the teeth 24. The teeth 24 are spaced apart circumferentially, with a stator coil 27 disposed between adjacent two teeth 24. The stator magnets 29 are arranged circumferentially. Each stator magnet 29 may be attached to the inner circumferential surface of the tooth 24 via adhesive, or to two fingers (not shown) extending radially inward from the inner circumferential surface of the tooth 24, or a combination of these. Regardless of the attachment method used, each of the stator magnets 29 faces a plurality of pole pieces 35 in the radial direction, with an outer air gap G2 between them.

[0022] When the power transmission device 2 illustrated in FIG. 1 transmits power from the input shaft 7 to the output shaft 8, the magnetic gear rotating machine 5 may function as a magnetic gear generator. Its operating principle is as follows: When power is input from the engine 3 to the input shaft 7, the magnet rotor 10 rotates. Electric power is generated in the stator coil 27 due to electromagnetic induction caused by the rotation of the multiple magnets 19. The control device 90 controls the electrical system 6, and the power is supplied to the electrical system 6. At the same time, the magnetic field between the stator 20 and the magnet rotor 10 changes due to a change in the circumferential positional relationship between the multiple magnets 19 and the multiple stator magnets 29. As a result, the multiple pole pieces 35 receive a magnetic force oriented in the circumferential direction. This causes the pole piece rotor 30 to rotate, and power is output from the output shaft 8 to the propeller shaft 4a, causing the vessel to sail. As described above, while the stator coil 27 generates power, the output shaft 8 rotates the propeller 4.

[0023] In the power transmission device 2, the magnetic gear rotating machine 5 may function as a magnetic gear motor. In this case, the output shaft 8 can rotate even if power is not input to the input shaft 7. The operating principle is as follows: The control device 90 controls the current flowing through the stator coil 27 using power supplied to the stator coil 27 from the electrical system 6. A rotating magnetic field is generated in the stator 20, causing the magnet rotor 10 to rotate together with the input shaft 7 (i.e., power can be transmitted from the input shaft 7 to the engine shaft 3a). At the same time, the magnetic field between the stator 20 and the magnet rotor 10 changes due to a change in the circumferential positional relationship between the multiple magnets 19 and the multiple stator magnets 29. As a result, the multiple pole pieces 35 are subjected to a magnetic force oriented in the circumferential direction. This causes the pole piece rotor 30 to rotate, and power is output from the output shaft 8 to the propeller shaft 4a. The rotation of the propeller 4 causes the marine vessel to sail. When motoring as described above is performed, power can be transmitted from the input shaft 7 to the propeller shaft 4a, and the engine 3 can be started.

[0024] In this example, whether the magnetic gear rotating machine 5 functions as a magnetic gear generator or a magnetic gear motor, the power for rotating the propeller 4 is transmitted to the output shaft 8 only from the pole piece rotor 30.

[0025] According to the above configuration, instead of a mechanical transmission including multiple meshing gears, a magnetic gear rotating machine 5 including a magnet rotor 10 and a pole piece rotor 30 spaced apart from each other is disposed between the input shaft 7 and the output shaft 8. This realizes a highly reliable power transmission device 2 that is less prone to breakdowns even over extended sailing times of the navigable vessel. Furthermore, meshing loss caused by meshing multiple gears can be reduced, improving the power transmission efficiency of the power transmission device 2. Therefore, the power transmission device 2 can also improve the fuel efficiency of the engine 3. Furthermore, in this embodiment, the functions of the reducer, generator, and electric motor, which were previously provided separately, can be integrated into the magnetic gear rotating machine 5, thereby reducing the space required for the engine system 1 and eliminating complex maintenance of the engine system 1. Furthermore, the reduced space required for the engine system 1 allows the input shaft 7 and output shaft 8 to be shortened, thereby suppressing torsional vibrations in the engine system 1. Furthermore, with the above configuration, whether the magnetic gear rotating machine 5 functions as a magnetic gear generator or a magnetic gear motor, the pole piece rotor 30 and the magnet rotor 10 are not in contact with each other, so even if a sudden load fluctuation occurs on the propeller 4, for example, when a foreign object in the water strikes the propeller 4 while the vessel is sailing, the magnetic gear rotating machine 5 can prevent step-out. Therefore, the load fluctuation is not transmitted to the engine 3, and the engine 3 can be protected.

[0026] <Additional Configuration of Power Transmission Device 2> With reference to Fig. 1, additional configurations that may be provided in the power transmission device 2 will be described. The power transmission device 2 may be configured to function as a reducer. That is, the magnet rotor 10 may function as a high-speed rotor, and the pole piece rotor 30 may function as a low-speed rotor. Therefore, when the magnetic gear rotating machine 5 functions as a magnetic gear generator, a rotation slower than the rotation input to the input shaft 7 is output from the output shaft 8.

[0027] A specific configuration for the power transmission device 2 to function as a reducer will be described. The number of magnetic poles of the pole pieces 35 of the pole piece rotor 30 is defined as NL, and the number of magnetic pole pairs (number of pole pairs) in the magnet 19 of the magnet rotor 10 is defined as NH. In this case, the ratio of the rotation speed of the pole piece rotor 30 to the rotation speed of the magnet rotor 10 is NH / NL. In this example, the magnetic gear rotating machine 5 is configured so that NH / NL is less than 1. As an example, the number of magnetic pole pairs (number of pole pairs) in the stator magnet 29 of the stator 20 is further defined as NS, and the magnetic gear rotating machine 5 is configured so that NL = NH + NS holds. In this case, NH / NL is less than 1, and the magnet rotor 10 and the pole piece rotor 30 can function as a high-speed rotor and a low-speed rotor, respectively.

[0028] With the above configuration, when the magnetic gear rotating machine 5 functions as a magnetic gear generator using power input to the input shaft 7, it can output a slower rotation from the output shaft 8 to the propeller 4 than the input shaft 7. Note that even when the magnetic gear rotating machine 5 functions as a magnetic gear motor using power supplied from the electrical system 6 to the stator coil 27, the rotation speed of the output shaft 8 can be made lower than the rotation speed of the input shaft 7.

[0029] The technical advantages of the magnetic gear rotating machine 5 functioning as a magnetic gear generator and / or magnetic gear motor as described above are as follows. Conventional controls based on load fluctuations on the propeller 4, such as fuel supply control for the engine 3, are no longer essential. This eliminates the need for precise control of the fuel injection amount based on load fluctuations, contributing to a reduction in fuel consumption. Furthermore, because the rotation speed of the output shaft 8 is lower than that of the input shaft 7, the torque output from the output shaft 8 to the propeller 4 is high. This makes the propeller 4 more robust against load fluctuations. On the other hand, when power is supplied to the stator coil 27, the propeller 4 can be motored, enabling more diverse rotation control of the propeller 4. This allows for more diverse operational control of the underwater vehicle. For example, it is possible to rotate the propeller 4 using both the power of the engine 3 and the rotational force of motoring, to cut off the power transmission path between the engine 3 and the input shaft 7 and rotate the propeller 4 only by motoring, and to switch the direction of rotation of the propeller 4 (details will be described later).

[0030] Referring to Figure 1, the description of additional components of the power transmission device 2 continues. The power transmission device 2 may further include a first clutch 11 disposed between the input shaft 7 and the engine shaft 3a. The first clutch 11 is configured to switch between a power transmission state and a power interruption state under the control of the control device 90. The power transmission state is a state in which the clutch transmits power, and the power interruption state is a state in which the clutch interrupts the transmission of power. The clutch used as the first clutch 11 may be an electromagnetic clutch or a hydraulic clutch.

[0031] Furthermore, the power transmission device 2 may include a second clutch 12 disposed between the output shaft 8 and the propeller shaft 4a. The second clutch 12 is the same type of clutch as the first clutch 11, and is configured to be switched between a power transmission state and a power cut-off state under the control of the control device 90.

[0032] The engine system 1 also includes an engine tachometer 91 for measuring the engine speed, which is the rotation speed of the engine shaft 3 a, and a propeller tachometer 92 for measuring the propeller speed, which is the rotation speed of the propeller shaft 4 a. The measurement results of the engine tachometer 91 and the propeller tachometer 92 are sent to the control device 90.

[0033] The configuration in which the first clutch 11 is provided makes it possible to interrupt the power transmission path between the engine shaft 3 a and the input shaft 7. In this case, it becomes possible to stop the rotating propeller 4 through the generation of electric power by the stator coil 27, and to motor the propeller 4 using the electric power supplied to the stator coil 27. Furthermore, when motoring, it becomes possible to more flexibly control the rotation of the propeller 4. More specifically, it becomes possible to control the rotation speed of the propeller 4 to be lower than when the propeller 4 is driven by the engine 3 alone, and to control the rotation direction of the propeller 4 to be switched (details will be described later).

[0034] As described above, when power is supplied to the stator coil 27, the engine 3 can also be started through motoring of the magnet rotor 10. According to the configuration in which the second clutch 12 is provided, the power transmission path between the output shaft 8 and the propeller 4 can be interrupted at this time. Since the power transmitted from the input shaft 7 to the engine shaft 3a increases, the engine 3 can be easily started. Furthermore, since the engine 3 can be started through motoring, an air line for starting the engine 3 is not required, and the configuration of the engine 3 can be simplified. Furthermore, in the above configuration in which both the first clutch 11 and the second clutch 12 are provided, the first clutch 11 can be placed in a power interruption state and the second clutch 12 can be placed in a power transmission state when the stator coil 27 generates power. At this time, the propeller 4, which is rotating by inertia, can be stopped by generating power through the stator coil 27.

[0035] <Overview of Electrical System 6 and Control Device 90> As illustrated in FIG. 3 , the electrical system 6 includes an inverter 41, a converter 42, a main switchboard 43, a load 44, and a battery 45. The inverter 41 is electrically connected to each of the stator coil 27, the converter 42, and the main switchboard 43. The converter 42 is electrically connected to the battery 45, and the main switchboard 43 is electrically connected to the load 44. The load 44 is one or more electrical devices installed on the underwater vehicle and is configured to operate by consuming supplied power. The battery 45 is an industrial storage battery capable of storing supplied power, such as a lithium-ion battery, alkaline storage battery, nickel-metal hydride battery, or lead-acid battery. Alternatively, the battery 45 may be a flywheel battery or a supercapacitor. The power stored in the battery 45 may be supplied to the stator coil 27 or the load 44.

[0036] At least one of the inverter 41, the converter 42, and the main switchboard 43 is equipped with a switching circuit. The transfer of power between the stator coil 27 and the electrical system 6 is controlled by switching the switching circuit. The switching of the switching circuit is performed by components of the control device 90, such as the motoring control unit 50 and the power generation control unit 70. For example, when the motoring control unit 50 switches the switching circuit, power is supplied from the battery 45 to the stator coil 27 via the inverter 41. At this time, the magnetic gear rotating machine 5 can function as a magnetic gear motor. On the other hand, when the power generation control unit 70 switches the switching circuit, power generated by the stator coil 27 (generated power) is supplied to the load 44 via the inverter 41, or to the battery 45 via the inverter 41 and the converter 42. Furthermore, the supply destination of the power stored in the battery 45 is switched between the stator coil 27 and the load 44 by switching the switching circuit.

[0037] 3, the control device 90 includes a clutch control unit 60 for controlling the first clutch 11 and the second clutch 12. The clutch control unit 60 is configured to send an actuation command and a disengagement command to each of the first clutch 11 and the second clutch 12. The actuation command is a command for switching the clutch from a power disconnection state to a power transmission state, and the disengagement command is a command for switching the clutch from a power transmission state to a power disconnection state.

[0038] 4 illustrates a detailed configuration of the clutch control unit 60. The clutch control unit 60 includes a first actuation control unit 61, a first release control unit 63, a second actuation control unit 62, and a second release control unit 64. The first actuation control unit 61 and the second actuation control unit 62 are configured to send actuation commands to the first clutch 11 and the second clutch 12, respectively. The first release control unit 63 and the second release control unit 64 are configured to send disengagement commands to the first clutch 11 and the second clutch 12, respectively.

[0039] <Engine Start Control> The operation of the engine system 1 when the engine 3 is started will be described with reference to Figures 5 to 7. In this embodiment, when the stopped engine 3 is started, the magnetic gear rotating machine 5 functions as a magnetic gear motor. Power is transmitted from the input shaft 7, which rotates by motoring, to the engine shaft 3a, causing the engine shaft 3a to start rotating. This causes the propeller 4 to start rotating, allowing the navigable vessel to start sailing.

[0040] The first clutch 11 is already in a power transmission state before the engine shaft 3 a starts to rotate. On the other hand, it is preferable that the second clutch 12 is switched to a power transmission state after the engine shaft 3 a starts to rotate. This is because a larger portion of the power generated by the magnetic gear rotating machine 5 through motoring can be used as power for starting the engine 3.

[0041] 5 shows the configuration of a control device 90 involved in such engine start. The control device 90 includes the above-mentioned first operation control unit 61 and second operation control unit 62. In the figure, the first operation control unit 61 is configured to send an operation command to the first clutch 11 before the engine shaft 3a starts to rotate, and the second operation control unit 62 is configured to send an operation command to the second clutch 12 after the engine shaft 3a starts to rotate.

[0042] Furthermore, the motoring control unit 50 of the control device 90 includes a motoring start unit 51 and a motoring stop unit 52. The motoring start unit 51 is configured to control a switching circuit of the electrical system 6 so that power is supplied from the electrical system 6 to the stator coil 27 when an actuation command is input to the first clutch 11. In this example, power for motoring is supplied from the battery 45 to the stator coil 27. The motoring stop unit 52 is configured to stop the supply of power from the electrical system 6 to the stator 20 when the engine speed reaches a threshold value (Sh in FIG. 6 ).

[0043] 6 shows the time-dependent changes in the engine speed, the first clutch 11, and the second clutch 12. In FIG. 6, "Transmission" indicates the "power transmission state" of the clutch, and "Disconnection" indicates the "power disconnection state" of the clutch.

[0044] As shown in the figure, first, the motoring start unit 51 switches the switching circuit to start motoring (at this time, the first clutch 11 is already in a power transmission state). At the same time, fuel is injected into the combustion chamber from the injection unit of the engine 3. The engine shaft 3a starts to rotate. When the engine speed reaches a threshold value (Sh in Figure 6), the engine shaft 3a can continue to rotate against rotational resistance without motoring. The motoring stop unit 52 switches the switching circuit, and motoring of the magnetic gear rotating machine 5 ends. Note that the main rotational resistance of the engine shaft 3a comes from frictional resistance in the cylinder unit composed of the cylinder, piston, etc., and viscous resistance of the oil inside the engine 3.

[0045] After the engine 3 starts, the engine speed increases further as fuel is injected, reaching the idle speed (Ri in FIG. 6 ). While the vessel is waiting to depart, the engine speed is maintained at Ri. Thereafter, as the vessel speed increases in preparation for departure, the second clutch 12 switches to a power transmission state, and the engine shaft 3a and the propeller shaft 4a each increase in speed.

[0046] 7 is a flowchart showing the engine start control process. The control process is executed by a processor constituting the control device 90. In the following, "step" may be abbreviated as "S."

[0047] First, the processor sends an actuation command to the first clutch 11 (S11). The first clutch 11 switches from a power cut-off state to a power transmission state, and the power transmission path between the input shaft 7 and the engine shaft 3a is connected. The processor that executes S11 is an example of the first actuation control unit 61.

[0048] Next, the processor switches the switching circuit of the electrical system 6 so that power is supplied from the electrical system 6 to the stator coil 27 (S13). At this time, power is supplied from the battery 45 to the stator coil 27, and the magnetic gear rotating machine 5 functions as a magnetic gear motor. Power is transmitted from the input shaft 7 to the engine shaft 3a via the first clutch 11. Also, when S13 is executed, fuel injection from the injection unit to the combustion chamber begins. Motoring and fuel supply cause the engine shaft 3a to start rotating. The processor that executes S13 is an example of a motoring start unit 51.

[0049] Next, the processor switches the switching circuit so as to stop the supply of power from the electrical system 6 to the stator 20 (S15). The processor may switch the switching circuit when the engine speed indicated by the measurement result of the engine tachometer 91 reaches a threshold value (Sh in FIG. 6). The processor terminates this control process. Note that even after this control process is terminated, fuel supply continues and the engine speed reaches the idle speed (Ri in FIG. 6). Thereafter, when the navigable vehicle sets sail, the second clutch 12 switches to the power transmission state. The processor that executes the process of switching the second clutch 12 to the power transmission state is an example of the second operation control unit 62.

[0050] According to the above configuration, when the engine 3 is started, power is supplied to the stator coil 27, thereby causing the engine shaft 3a to start rotating. Since the engine intake volume increases immediately when the engine 3 is started by motoring, it is possible to prevent a large amount of incompletely burned gas from being emitted as black smoke when the engine 3 is started. In addition, an air line for starting the engine 3 is no longer necessary, which simplifies the configuration of the engine 3.

[0051] Furthermore, before starting the engine 3 by motoring, the second clutch 12 is maintained in a power-disconnected state, thereby disconnecting the power transmission path between the pole piece rotor 30 and the propeller 4. Because the power transmitted from the input shaft 7 to the engine shaft 3a increases, the engine system 1 can supply the engine 3 with the relatively large power required to start rotating the engine shaft 3a. This allows the engine 3 to start easily. Furthermore, after the engine shaft 3a starts rotating, the power transmission path between the pole piece rotor 30 and the propeller 4 is connected, allowing the propeller 4 to gradually increase its speed.

[0052] <Normal Power Generation Operation> The normal power generation operation of the engine system 1 will be described with reference to Figures 8 to 10. The normal power generation operation is performed while the engine speed is equal to or higher than a specified speed. In this example, engine efficiency varies significantly depending on whether the engine speed is equal to or higher than the specified speed. More specifically, when the engine speed is equal to or higher than the specified speed, engine efficiency is relatively high, and when the engine speed is lower than the specified speed, engine efficiency is relatively low. If the power generation operation is performed while the engine speed is equal to or higher than the specified speed, the engine system 1 can achieve both efficient operation of the engine 3 and power generation. The specified speed may be the same value as the idle speed (Ri) shown in Figure 6.

[0053] Furthermore, in order to perform normal power generation operation according to this embodiment, a power generation condition must be satisfied. The power generation condition is satisfied when the propeller rotation speed is equal to or greater than the required rotation speed input by the pilot of the watercraft. If the power generation condition is not satisfied, normal power generation operation is not performed even if the engine rotation speed is equal to or greater than the specified rotation speed, and motoring is performed instead. For example, if the watercraft experiences high resistance due to a reverse tide or a headwind, the required rotation speed increases due to a decrease in the watercraft speed. In this case, the power generation condition is not satisfied, and motoring is performed. As another example, if foreign matter such as algae becomes entangled in the propeller 4 while the watercraft is sailing, the propeller rotation speed decreases and the power generation condition is no longer satisfied. In this case, motoring is performed. Motoring is performed until the propeller rotation speed reaches or exceeds the required rotation speed (i.e., until the power generation condition is satisfied).

[0054] 8 shows the configuration of a control device 90 for realizing normal power generation operation. The power generation control section 70 of the control device 90 includes a power generation start section 71 and a power generation stop section 72.

[0055] The power generation start unit 71 is configured to control the switching circuit of the electrical system 6 so as to start supplying generated power from the stator coil 27 to the electrical system 6. This control is executed when the power generation condition is met, that is, when the engine speed measured by the engine tachometer 91 is equal to or higher than a specified speed. The generated power may be supplied to the load 44 or to the battery 45. In other words, the power generation control unit 70 may control the electrical system 6 so as to supply the generated power to the load 44, or may control the electrical system 6 so as to supply the generated power to the battery 45. The power generation stop unit 72 is configured to control the switching circuit of the electrical system 6 so as to stop supplying generated power from the stator coil 27 when the power generation condition is no longer met.

[0056] The control device 90 further includes a motoring speed-up control unit 57 for controlling the electrical system 6 after the power generation stop unit 72 has stopped generating power. The motoring speed-up control unit 57 is configured to control the switching circuit so that power for increasing the propeller rotation speed is supplied from the electrical system 6 to the stator coil 27. The control by the motoring speed-up control unit 57 is similar to that of the motoring control unit 50 (see FIG. 3 ).

[0057] FIG. 9 shows the change in propeller rotation speed over time during normal power generation. When the propeller rotation speed reaches the required rotation speed (Rp), it is determined that the power generation conditions are met, and the power generation start unit 71 starts power generation. When the propeller rotation speed falls below the required rotation speed (t = t1), the power generation stop unit 72 stops supplying generated power, and the motoring acceleration control unit 57 starts motoring. The propeller 4 rotates by receiving not only the power input from the engine 3 via the input shaft 7, but also the power generated by motoring. In other words, the propeller 4 rotates by both the power of the engine 3 and the rotational force of motoring. This increases the rotation speed of the propeller 4. Thereafter, when the generated power is again sufficient (t = t2), the control by the motoring acceleration control unit 57 ends, and the power generation start unit 71 resumes power generation control.

[0058] 10 is a flowchart showing the normal power generation control process, which is executed by the processor constituting the control device 90 while the engine speed is equal to or higher than a specified speed.

[0059] First, the processor determines whether the power generation conditions are met based on the measurement result of the propeller tachometer 92 (S21). While the propeller rotation speed measured by the propeller tachometer 92 is less than the required rotation speed (S21: NO), the processor waits. When the measured propeller rotation speed becomes equal to or greater than the required rotation speed, the processor determines that the power generation conditions are met (S21: YES). Thereafter, the processor controls the switching circuit so that generated power is supplied from the stator coil 27 to the electrical system 6 (S23). The generated power may be supplied to either the load 44 or the battery 45. The processor that executes S23 is an example of the power generation start unit 71.

[0060] Next, the processor again determines whether the power generation conditions are satisfied (S25). As long as the measured propeller rotation speed is equal to or greater than the required rotation speed (S25: YES), the processor waits, and the stator coil 27 continues to generate power. When the propeller rotation speed falls below the required rotation speed, the processor determines that the power generation conditions are no longer satisfied (S25: NO). Then, the processor controls the switching circuit of the electrical system 6 to stop the supply of generated power from the stator coil 27 (S27). The processor that executes S27 is an example of the power generation stopping unit 72.

[0061] Next, the processor controls the switching circuit of the electrical system 6 so that power for increasing the propeller rotation speed is supplied to the stator coil 27 (S29). The processor that executes S29 is an example of the motoring acceleration control unit 57. Execution of S29 increases the propeller rotation speed. The processor then proceeds to S21. If it is determined in S21 that the power generation condition is satisfied again (S21: YES), the processor stops the supply of motoring power and resumes the supply of generated power (S23). The control process described above is executed while the marine vessel is sailing.

[0062] The technical advantages of normal power generation operation are as follows. The range of engine speed includes a range where the engine efficiency is relatively high and a range where it is not. In this regard, with the above-described configuration, normal power generation operation is initiated when the engine speed is equal to or higher than a specified speed and the engine efficiency is relatively high. This allows the engine system 1 to operate efficiently.

[0063] In the above embodiment, when the engine efficiency is relatively high and the propeller rotation speed is equal to or higher than the required rotation speed, power generation is started in the stator coil 27. This allows the vessel to travel at a specified speed and generate power while the engine 3 is operating efficiently.

[0064] In the above embodiment, when the propeller rotation speed falls below the required rotation speed, power generation by the stator coil 27 is stopped and motoring is performed. In this way, the propeller rotation speed is controlled while maintaining the engine rotation speed within a rotation speed range that achieves high engine efficiency, allowing the engine system 1 to operate efficiently as a whole. Furthermore, since control for significantly changing the engine rotation speed can be suppressed, fuel injection control of the engine 3 can be simplified compared to conventional methods. Furthermore, load fluctuations in the engine 3 can be reduced, thereby improving the reliability of the engine 3.

[0065] Furthermore, when the power generation starting unit 71 of the power generation control unit 70 controls the stator coil 27 to supply generated power to the load 44 of the electrical system 6, the generated power from the stator coil 27 can be supplied to various devices mounted on the marine vehicle, thereby contributing to the power supply of the marine vehicle.

[0066] Furthermore, when the generated power is supplied from the stator coil 27 to the battery 45 of the electrical system 6 under the control of the power generation starting unit 71 of the power generation control unit 70, the power stored in the battery 45 can be used at any desired timing. More specifically, the power of the battery 45 can be used as power for motoring the magnetic gear rotating machine 5 and / or as power to be supplied to the load 44 of the marine vehicle.

[0067] <Control of Regenerative Power Generation> The regenerative power generation operation of the engine system 1 will be described with reference to Figures 11 to 13. This operation is for generating power while the maritime vessel is decelerating, and differs from the normal power generation operation described above, which is performed while the engine speed is equal to or greater than a specified speed. Furthermore, when regenerative power is being generated, the first clutch 11 switches to a power cut-off state, and the propeller 4 continues to rotate by inertia. The energy required to brake the inertial rotation of the propeller 4 is recovered as generated power, thereby reducing energy loss. As an example, regenerative power is generated when the maritime vessel stops at its destination.

[0068] FIG. 11 shows the configuration of a control device 90 for realizing the operation of generating regenerative power. The control device 90 includes an engine deceleration control unit 95 for inputting a deceleration command to the engine 3 to cause the rotating engine shaft 3a to begin decelerating. When the deceleration command is input to the engine 3, the amount of fuel supplied to the combustion chamber of the engine 3 is reduced, and the engine shaft 3a decelerates. The control device 90 also includes the above-mentioned clutch control unit 60. FIG. 11 shows only the first release control unit 63 of the clutch control unit 60, and the first release control unit 63 illustrated in the same figure is configured to send a disengagement command to the first clutch 11 when a deceleration command is input to the engine 3.

[0069] The control device 90 further includes a regenerative power generation control unit 75. The regenerative power generation control unit 75 is configured to control the electrical system 6 so that generated power (regenerated power) is supplied from the stator coil 27 when a deceleration command is input to the engine 3. More specifically, under the control of the regenerative power generation control unit 75, the regenerative power is supplied from the stator coil 27 to the battery 45. The control of the regenerative power generation control unit 75 is similar to the control of the power generation start unit 71 (see FIG. 8 ), and a detailed description thereof will be omitted here.

[0070] During the period from when the propeller 4 starts to decelerate until it stops, the control device 90 does not send a disengagement command to the second clutch 12, and the second clutch 12 is maintained in a power transmission state. As a result, the rotational energy of the propeller 4 is recovered as electric power energy.

[0071] 12 shows the change in propeller rotation speed over time when regenerative power is being generated. When a deceleration command is input to the engine 3 (t=t3), the propeller rotation speed decreases and the regenerative power generation control unit 75 starts generating regenerative power. This control is executed until the propeller 4 stops.

[0072] 13 is a flowchart showing a process for controlling the generation of regenerative power. This control process is executed by a processor constituting the control device 90. When this control process is executed, the second clutch 12 is maintained in a power transmitting state.

[0073] First, the processor inputs a deceleration command to the engine 3 (S31). The processor that executes S31 is an example of the engine deceleration control unit 95. Next, the processor sends a disengagement command to the first clutch 11 (S33). The first clutch 11 switches from a power transmission state to a power cut-off state, and the propeller 4 rotates by inertia. The processor that executes S33 is an example of the first release control unit 63. Next, the processor controls the switching circuit of the electrical system 6 so that generated power (regenerated power) is supplied from the stator coil 27 (S35). S35 is executed continuously until the propeller rotation speed becomes 0, and then this control process ends. The processor that executes S35 is an example of the regenerative power generation control unit 75.

[0074] The technical advantages of the regenerative power generation operation will now be described. According to the above configuration, when the engine speed of the navigating vessel decreases to stop at the destination, the first clutch 11 enters a power cut-off state, and the power transmission path between the engine 3 and the input shaft 7 is interrupted. Then, the rotating propeller 4 can be decelerated while recovering regenerative power from the stator coil 27. This reduces the energy loss from when the navigating vessel starts to decelerate until it stops, allowing the engine system 1 to operate more efficiently.

[0075] Furthermore, when the engine speed of the vessel is reduced to stop at the destination while sailing, the second clutch 12 is maintained in a power transmission state, so that the rotational force of the propeller 4 can be used to generate electricity in the stator 20.

[0076] Furthermore, the battery 45 can be charged with the regenerative power generated by the stator 20. This makes it possible to use the power stored in the battery 45 at a desired timing to motor the magnetic gear rotating machine 5 and / or to supply power to the load 44 of the navigation vehicle.

[0077] <Power Generation Operation While the Vessel is at Anchorage> The power generation operation of the engine system 1 while the vessel is at anchor will be described with reference to Figures 14 and 15. This operation is for generating power while the vessel is at anchor, and may be performed after the operation for generating regenerative power. During the power generation operation while the vessel is at anchor, power is input from the engine 3 to the power transmission device 2. However, at this time, the second clutch 12 is maintained in a power cut-off state, and power is not transmitted from the output shaft 8 to the propeller 4. Therefore, while the rotation of the input shaft 7 rotates the magnet rotor 10 and the pole piece rotor 30, the propeller 4 does not rotate, and the vessel remains stationary.

[0078] 14 shows the configuration of a control device 90 for realizing an anchored power generation operation. The control device 90 includes a stop determination unit 97 for determining whether the marine vessel has come to a stop. The stop determination unit 97 is configured to acquire the measurement results of at least one of the propeller tachometer 92 and the engine tachometer 91. For example, if the propeller rotation speed measured by the propeller tachometer 92 is less than the first propeller rotation speed and the engine rotation speed measured by the engine tachometer 91 is less than the first engine rotation speed, it is determined that the engine 3 is in a stopped state. The first propeller rotation speed and the first engine rotation speed may be different values ​​or may be the same value (e.g., 0).

[0079] The control device 90 further includes a clutch switching control unit 65. The clutch switching control unit 65 is configured to send an actuation command to the first clutch 11 and a disengagement command to the second clutch 12 when the stop determination unit 97 determines that the engine 3 is in a stopped state. The control of the clutch switching control unit 65 is similar to the control of the clutch control unit 60 (see FIG. 3 ), and a detailed description thereof will be omitted here.

[0080] The control device 90 further includes an anchorage power generation control unit 77. The anchorage power generation control unit 77 is configured to control the electrical system 6 so that generated power is supplied from the stator coil 27 after the clutch switching control unit 65 has executed control. More specifically, the anchorage power generation control unit 77 controls the generated power to be supplied from the stator coil 27 to the battery 45. The control of the anchorage power generation control unit 77 is similar to the control of the power generation start unit 71 (see FIG. 8 ), and a detailed description thereof will be omitted here.

[0081] 15 is a flowchart showing the control process for power generation at anchor. The control process is executed by a processor constituting the control device 90.

[0082] First, the processor determines whether the watercraft has come to a stop (S41). More specifically, if the propeller rotation speed measured by the propeller tachometer 92 is less than the first propeller rotation speed and the engine rotation speed measured by the engine tachometer 91 is less than the first engine rotation speed, the engine 3 is determined to be in a stopped state. The processor waits until the watercraft comes to a stop (S41: NO). For example, while the regenerative power generation control process (see FIG. 13 ) is being executed, the watercraft is decelerating and is not in a stopped state. At this time, the processor waits. If it is determined that the watercraft has come to a stop (S41: YES), the processor proceeds to S43. The processor executing S41 is an example of the stop determination unit 97.

[0083] Next, the processor executes clutch switching control (S43). More specifically, the processor sends an actuation command to the first clutch 11 and a disengagement command to the second clutch 12. The processor that executes S43 is an example of the clutch switching control unit 65. By executing S43, power from the engine 3 can be input to the input shaft 7, while the power transmission path between the output shaft 8 and the propeller 4 is interrupted. Therefore, both the magnet rotor 10 and the pole piece rotor 30 rotate, while the propeller 4 does not rotate.

[0084] Next, the processor controls the electrical system 6 so that generated power is supplied from the stator coil 27 (S45). The processor that executes S45 is an example of the berthing power generation control unit 77. After execution of S45, this control process ends.

[0085] When S45 is executed, a command to increase the engine speed may be input to the engine 3. For example, if the necessary condition for the stop condition to be satisfied in S41 is that the engine speed is less than the first engine speed, the engine speed will be low when the affirmative determination is made in S41, and therefore the command may be necessary to execute power generation.

[0086] In another embodiment, the stop determination unit 97 may determine that the watercraft is stopped as long as the engine speed is less than the first engine speed, regardless of the propeller speed. In this case, the stop determination unit 97 does not need to monitor the measurement results of the propeller tachometer 92.

[0087] <Propeller 4 Rotation Control Operation> The propeller 4 rotation control operation will be described with reference to Figures 16 to 18. In this operation, the propeller 4 rotates in either a first direction or a second direction, allowing the rotation direction of the propeller 4 to be switched. This control is performed, for example, when a berthed vessel moves forward or backward. In this operation, the rotation speed of the propeller 4 can also be controlled through control of the current flow through the stator coil 27, making it possible to broaden the range of values ​​over which the propeller rotation speed is maintained constant while the vessel is sailing (propeller rotation speed range). It is preferable that the engine 3 be operated at a relatively high rotation speed to achieve high engine efficiency. Therefore, the rotation speed of the propeller 4 driven by the engine 3 may be limited to a relatively high range. In contrast, motoring-based rotation control of the propeller 4 does not involve the above-mentioned constraints, allowing for a wider range of propeller rotation speeds.

[0088] 16 shows the configuration of a control device 90 for realizing the rotation control operation of the propeller 4. The motoring control unit 50 of the control device 90 includes a first motoring control unit 53 and a second motoring control unit 54. The first motoring control unit 53 is configured to control the electric system 6 so that a first electric power for rotating the propeller 4 in a first direction is supplied from the electric system 6 to the stator coil 27. The second motoring control unit 54 is configured to control the electric system 6 so that a second electric power for rotating the propeller 4 in a second direction is supplied from the electric system 6 to the stator coil 27.

[0089] Whether the propeller 4 rotates in the first direction or the second direction is determined by the direction of current in each of the multiple stator coils 27 and the order in which power is supplied to the multiple stator coils 27. The control of each of the first motoring control unit 53 and the second motoring control unit 54 is similar to the control of the motoring start unit 51 (see FIG. 5 ).

[0090] 17 shows the change over time in the propeller rotation speed when rotation control of the propeller 4 is executed. When the first motoring control unit 53 controls the electric system 6, the propeller rotation speed takes a positive value (t4≦t≦t5), and when the second motoring control unit 54 controls the electric system 6, the propeller rotation speed takes a negative value (t6≦t≦t7).

[0091] 18 is a flowchart showing the rotation control process for the propeller 4. This control process is executed by a processor constituting the control device 90. When this control process is executed, the first clutch 11 and the second clutch 12 are both in a power transmitting state, and the engine 3 is in operation.

[0092] First, the processor controls the stator core 22 so that the propeller 4 rotates in a first direction (S51). Then, the processor controls the stator core 22 so that the propeller 4 rotates in a second direction (S53). After execution of S53, this control process ends. The processor that executes S51 is an example of the first motoring control unit 53, and the processor that executes S53 is an example of the second motoring control unit 54.

[0093] The above configuration allows the vessel to move forward and backward, making it possible to operate the vessel more flexibly. For example, a vessel at anchor can move slightly forward or backward at low speed. In addition, since a reversing device for reversing the propeller 4 is not required, the engine system 1 can be simplified.

[0094] <Others> The control device 90 (see FIG. 1) described above is configured by a computer and includes a processor, memory (storage medium), and an external communication interface. The processor is a CPU, GPU, MPU, DSP, or a combination thereof. The processor according to other embodiments may be realized by an integrated circuit such as a PLD, ASIC, FPGA, or MCU. The memory is configured to temporarily or non-temporarily store various data and is realized by at least one of a RAM, a ROM, and a flash memory, for example. The processor executes various control processes according to instructions from a program loaded into the memory.

[0095] <Summary> The contents described in the above-described embodiments can be understood, for example, as follows.

[0096] 1) A power transmission device (2) according to at least one embodiment of the present disclosure is a power transmission device (2) configured to transmit power from an engine (3) installed on a watercraft that travels at least one of on water and underwater to a propeller (4) of the watercraft, and includes: an input shaft (7) configured to input the power from the engine; an output shaft (8) configured to output the power to the propeller; and a magnetic gear rotating machine (5) that magnetically couples the input shaft and the output shaft, wherein the magnetic gear rotating machine includes: a magnet rotor (10) connected to the input shaft; a pole piece rotor (30) connected to the output shaft; and a stator (20) having a stator core (22) extending circumferentially radially outward of the pole piece rotor; and a stator coil (27) arranged in the stator core.

[0097] According to the configuration 1) above, instead of a mechanical transmission including multiple gears that mesh with each other, a magnetic gear rotating machine including a magnet rotor and a magnetic pole piece rotor that are spaced apart is disposed between the input shaft and the output shaft. This realizes a highly reliable power transmission device that is less likely to break down even when the cruising time of the vessel is long. Furthermore, since meshing loss caused by multiple gears meshing can be reduced, the power transmission efficiency of the power transmission device is improved. As a result, the power transmission device can also improve the fuel efficiency of the engine.

[0098] 2) In some embodiments, in the power transmission device described in 1) above, the magnetic gear rotating machine is configured to use the power input from the engine to the input shaft to output a slower rotation from the output shaft to the propeller than the input shaft and to generate electricity in the stator coil, and / or to rotate the propeller using the power supplied to the stator coil.

[0099] The configuration described in 2) above eliminates the need for precise control of the fuel supply to the engine in response to propeller load fluctuations, contributing to a reduction in fuel consumption. Furthermore, because the rotation speed of the output shaft is lower than that of the input shaft, the torque output from the output shaft to the propeller is high. This makes the propeller more resistant to load fluctuations. On the other hand, when power is supplied to the stator coil, the propeller can be motored, allowing for more diverse propeller rotation control. This allows for more diverse operational control of the watercraft. For example, it is possible to rotate the propeller using both engine power and motoring torque, to cut off the power transmission path between the engine and the input shaft and rotate the propeller only by motoring, and to switch the propeller rotation direction.

[0100] 3) In some embodiments, the power transmission device according to 2) above further comprises a first clutch (11) disposed between the input shaft and the engine shaft (3a) of the engine.

[0101] According to the configuration 3) above, the power transmission path between the engine shaft and the input shaft can be interrupted. In this case, it is possible to stop the rotating propeller by generating electric power using the stator coil, and to motor the propeller using the electric power supplied to the stator coil. This allows for more flexible control of the propeller rotation during motoring. More specifically, it is possible to control the propeller rotation speed to be lower than when the propeller is driven by the engine alone, and to control the propeller rotation direction.

[0102] 4) In some embodiments, the power transmission device according to 2) or 3) above further comprises a second clutch (12) disposed between the output shaft and the propeller shaft (4a) of the propeller.

[0103] When power is supplied to the stator coil, the engine can also be started through motoring of the magnet rotor. According to the configuration of 4) above, the power transmission path between the output shaft and the propeller can be cut off at this time. Since the power transmitted from the input shaft to the engine shaft increases, the engine can be started easily. Furthermore, since the engine can be started through motoring, an air line for starting the engine is not required, and the engine configuration can be simplified. Furthermore, when the first clutch described above is provided, the first clutch can be put into a power cut-off state and the second clutch can be put into a power transmission state when power is generated by the stator coil. In this case, the propeller rotating by inertia can be stopped by generating power by the stator coil.

[0104] 5) A watercraft engine system (1) according to at least one embodiment of the present invention comprises: a power transmission device (2) according to any one of 1) to 4) above; an engine (3) installed on the watercraft; a propeller (4) installed on the watercraft; an electrical system (6) electrically connected to the stator coil; and a control device (90) for controlling the power transmission device, the engine, and the electrical system.

[0105] The configuration 5) above provides the same technical advantages as the configuration 1).

[0106] 6) In some embodiments, in the underwater vehicle engine system described in 5) above, the power transmission device further includes a first clutch (11) arranged between the input shaft and an engine shaft (3a) of the engine, and the control device includes: a first operation control unit (61) for sending an operation command to the first clutch to switch from a power cut-off state to a power transmission state when the engine starts; and a motoring control unit (50) for controlling the electrical system so that power is supplied from the electrical system to the stator coil when the operation command is input to the first clutch.

[0107] According to the configuration of 6) above, when the engine is started, power is supplied to the stator coil, which causes the engine shaft to begin rotating. Since the engine intake volume increases immediately when the engine is started by motoring, it is possible to prevent a large amount of incompletely burned gas from being emitted as black smoke when the engine is started. Furthermore, an air line for starting the engine is no longer necessary, simplifying the engine configuration.

[0108] 7) In some embodiments, in the underwater vehicle engine system described in 6) above, the power transmission device further includes a second clutch (12) arranged between the output shaft and the propeller shaft (4a) of the propeller, and the control device further includes a second actuation control unit (62) for sending the actuation command to the second clutch after the engine shaft starts to rotate.

[0109] According to the configuration of 7) above, before starting the engine by motoring, the second clutch is maintained in a power-disconnected state, and the power transmission path between the pole piece rotor and the propeller is interrupted. This increases the power transmitted from the input shaft to the engine shaft, making it easier to start the engine. Furthermore, after the engine shaft begins to rotate, the power transmission path between the pole piece rotor and the propeller is connected, allowing the propeller to gradually increase speed.

[0110] 8) In some embodiments, the underwater vehicle engine system described in 6) or 7) above further includes an engine tachometer (91) for measuring the engine speed of the engine, and the control device further includes a power generation control unit (70) for controlling the electrical system so that generated power is supplied from the stator coil when the engine speed measured by the engine tachometer becomes equal to or exceeds a specified speed.

[0111] Generally, the range of engine speeds includes a range where the engine efficiency is relatively high and a range where it is not. In this regard, with the configuration of 8) above, when the engine speed is equal to or higher than the specified speed and the engine efficiency is relatively high, the stator coil can supply generated power to the electrical system. This allows the aircraft engine system to operate efficiently.

[0112] 9) In some embodiments, the underwater vehicle engine system described in 8) above further includes a propeller tachometer (92) for measuring the propeller rotation speed of the propeller, and the power generation control unit includes a power generation start unit (71) for starting the supply of the generated power from the stator coil to the electrical system when a power generation condition is satisfied in which the propeller rotation speed measured by the propeller tachometer is equal to or greater than a required rotation speed when the engine rotation speed measured by the engine tachometer is equal to or greater than the specified rotation speed.

[0113] According to the configuration of 9) above, when the engine efficiency is relatively high and the propeller rotation speed is equal to or higher than the required rotation speed, power generation by the stator coil is started, thereby making it possible to run the watercraft at a specified speed and generate power under conditions where the engine is operating efficiently.

[0114] 10) In some embodiments, in the underwater vehicle engine system described in 9) above, the power generation control unit further includes a power generation stopping unit (72) for stopping the supply of generated power from the stator coil when the power generation condition is no longer satisfied in a case where the engine speed measured by the engine tachometer is equal to or greater than the specified speed, and the control device further includes a motoring speed increase control unit (57) for controlling the electrical system so that power for increasing the propeller speed is supplied to the stator coil after the generated power is stopped by the power generation stopping unit.

[0115] According to the configuration of 10) above, when the propeller rotation speed falls below the required rotation speed, power generation by the stator coil is stopped and motoring is performed. The propeller rotation speed increases, and the power generation condition is eventually met again. In this way, the propeller rotation speed is controlled while maintaining the engine rotation speed within a rotation speed range that achieves high engine efficiency, allowing the aircraft engine system as a whole to operate efficiently. Furthermore, since control to significantly change the engine rotation speed can be suppressed, engine fuel injection control can be simplified compared to conventional systems. Furthermore, load fluctuations in the engine can be reduced, improving engine reliability.

[0116] 11) In some embodiments, in the underwater vehicle engine system described in any one of 6) to 10) above, the control device further includes: an engine deceleration control unit (95) for inputting a deceleration command to the engine so that the rotating engine shaft begins to decelerate; a first release control unit (63) for sending a disconnection command to the first clutch to switch from the power transmission state to the power cut-off state when the deceleration command is input to the engine; and a regenerative power generation control unit (75) for controlling the electrical system so that generated power is supplied from the stator coil when the deceleration command is input to the engine.

[0117] According to the configuration of 11) above, when the engine speed of the navigable vessel decreases to stop at the destination, the first clutch enters a power cut-off state, cutting off the power transmission path between the engine and the input shaft. The rotating propeller can then be decelerated while recovering generated power as regenerative power from the stator coil. This reduces the energy loss from when the navigable vessel starts to decelerate until it stops, allowing the navigable vessel engine system to operate more efficiently.

[0118] 12) In some embodiments, in the underwater vehicle engine system described in 11) above, the power transmission device further includes a second clutch (12) disposed between the output shaft and the propeller shaft (4a) of the propeller, and the control device is configured to maintain the second clutch in the power transmission state until the rotating propeller begins to decelerate and then stops.

[0119] According to the configuration of 12) above, when the engine speed of the vessel is reduced so that the vessel can stop at its destination while sailing, the second clutch is maintained in a power transmission state, so that the rotational force of the propeller can be used to generate electricity in the stator.

[0120] 13) In some embodiments, in the underwater vehicle engine system described in 12) above, the electrical system includes a battery (45), and the regenerative power generation control unit is configured to control the electrical system so that the generated power is supplied from the stator coil to the battery.

[0121] According to the configuration of 13) above, the battery can be charged with the power generated as regenerative power in the stator, which makes it possible to use the power stored in the battery at a desired timing to motor the magnetic gear rotating machine and / or to supply power to the load of the underwater vehicle.

[0122] 14) In some embodiments, in the underwater vehicle engine system described in any one of 8) to 10) above, the power generation control unit is configured to control the electrical system so that the generated power is supplied from the stator coil to a load (44) of the electrical system.

[0123] According to the configuration of 14) above, the generated electric power produced by the stator coil can be supplied to various devices mounted on the watercraft, thereby contributing to the power supply of the watercraft.

[0124] 15) In some embodiments, the underwater vehicle engine system is described in any one of 8) to 10) above, wherein the electrical system includes a battery (45), and the power generation control unit is configured to control the electrical system so that the generated power is supplied from the stator coil to the battery.

[0125] The configuration 15) above provides the same technical advantages as the configuration 13).

[0126] 16) In some embodiments, the underwater vehicle engine system described in any of 6) to 15) above further includes at least one of a propeller tachometer (92) for measuring the propeller rotation speed of the propeller or an engine tachometer (91) for measuring the engine rotation speed of the engine, and the control device includes: a stop determination unit (97) for determining whether the underwater vehicle has come to a stop based on at least one of the propeller tachometer or the engine tachometer; a clutch switching control unit (65) configured to, when it is determined that the underwater vehicle has come to a stop, send a disconnection command to the second clutch to switch from the power transmission state to the power cut-off state, and send the operation command to the first clutch; and an anchorage power generation control unit (77) for controlling the electrical system so that generated power is supplied from the stator coil after control is performed by the clutch switching control unit.

[0127] According to the configuration of 16) above, the vessel engine system can generate electricity even while the vessel is at anchor.

[0128] 17) In some embodiments, in the underwater vehicle engine system described in any one of 5) to 16) above, the control device further includes: a first motoring control unit (53) for controlling the electrical system so that a first electric power for rotating the propeller in a first direction is supplied from the electrical system to the stator coil; and a second motoring control unit (54) for controlling the electrical system so that a second electric power for rotating the propeller in a second direction is supplied from the electrical system to the stator coil.

[0129] The configuration of 17) above allows the vessel to move forward and backward, making it possible to operate the vessel more flexibly. For example, a vessel at anchor can move slightly forward or backward at low speed. In addition, since a reversing device for reversing the propeller is not required, the vessel engine system can be simplified.

[0130] REFERENCE SIGNS LIST 1: Vehicle engine system (engine system) 2: Power transmission device 3: Engine 3a: Engine shaft 4: Propeller 4a: Propeller shaft 5: Magnetic gear rotating machine 6: Electrical system 7: Input shaft 8: Output shaft 10: Magnet rotor 11: First clutch 12: Second clutch 15: Rotor core 19: Magnet 20: Stator 22: Stator core 24: Teeth 27: Stator coil 29: Stator magnet 30: Pole piece rotor 31: First connecting portion 32: Second connecting portion 33: Non-magnetic material 35: Pole piece 41: Inverter 42: Converter 43: Main switchboard 44: Load 45: Battery 50: Motoring control unit 51: Motoring start unit 52: Motoring stop section 53: First motoring control section 54: Second motoring control section 57: Motoring acceleration control section 60: Clutch control section 61: First operation control section 62: Second operation control section 63: First release control section 64: Second release control section 65: Clutch switching control section 70: Power generation control section 71: Power generation start section 72: Power generation stop section 75: Regenerative power generation control section 77: Berthing power generation control section 90: Control device 91: Engine tachometer 92: Propeller tachometer 95: Engine deceleration control section 97: Stop determination section B1: Bearing G1: Inner air gap G2: Outer air gap

Claims

1. A power transmission device configured to transmit power from an engine installed on a vessel that travels at least either on water or underwater to a propeller of the vessel, comprising: an input shaft configured to input the power from the engine; an output shaft configured to output the power to the propeller; and a magnetic gear rotating machine that magnetically couples the input shaft and the output shaft, wherein the magnetic gear rotating machine includes: a magnet rotor connected to the input shaft; a pole piece rotor connected to the output shaft; and a stator having a stator core extending circumferentially radially outside the pole piece rotor and a stator coil arranged in the stator core.

2. The power transmission device according to claim 1, wherein the magnetic gear rotating machine is configured to use the power input from the engine to the input shaft to output slower rotation from the output shaft to the propeller than the input shaft and to generate electricity in the stator coil, and / or to rotate the propeller using power supplied to the stator coil.

3. The power transmission device according to claim 2, further comprising a first clutch disposed between the input shaft and an engine shaft of the engine.

4. The power transmission device according to claim 2 or 3, further comprising a second clutch disposed between the output shaft and a propeller shaft of the propeller.

5. A watercraft engine system comprising: a power transmission device according to any one of claims 1 to 3; an engine installed on the watercraft; a propeller installed on the watercraft; an electrical system electrically connecting the stator coil; and a control device for controlling the power transmission device, the engine, and the electrical system.

6. The underwater vehicle engine system of claim 5, wherein the power transmission device further includes a first clutch disposed between the input shaft and an engine shaft of the engine, and the control device includes: a first operation control unit for sending an operation command to the first clutch to switch from a power cut-off state to a power transmission state when the engine starts; and a motoring control unit for controlling the electrical system so that power is supplied from the electrical system to the stator coil when the operation command is input to the first clutch.

7. The underwater vehicle engine system described in claim 6, wherein the power transmission device further includes a second clutch disposed between the output shaft and a propeller shaft of the propeller, and the control device further includes a second operation control unit for sending the operation command to the second clutch after the engine shaft starts to rotate.

8. The underwater vehicle engine system of claim 6, further comprising an engine tachometer for measuring an engine speed of the engine, wherein the control device further includes a power generation control unit for controlling the electrical system so that generated power is supplied from the stator coil when the engine speed measured by the engine tachometer becomes equal to or higher than a specified speed.

9. The underwater vehicle engine system of claim 8, further comprising a propeller tachometer for measuring the propeller rotation speed of the propeller, wherein the power generation control unit includes a power generation start unit for starting the supply of the generated power from the stator coil to the electrical system when a power generation condition is satisfied in which the propeller rotation speed measured by the propeller tachometer becomes equal to or greater than a required rotation speed when the engine rotation speed measured by the engine tachometer is equal to or greater than the specified rotation speed.

10. The underwater vehicle engine system of claim 9, wherein the power generation control unit further includes a power generation stopping unit for stopping the supply of generated power from the stator coil when the power generation condition is no longer satisfied when the engine speed measured by the engine tachometer is equal to or higher than the specified speed, and the control device further includes a motoring acceleration control unit for controlling the electrical system so that power for increasing the propeller speed is supplied to the stator coil after the generated power is stopped by the power generation stopping unit.

11. The underwater vehicle engine system of claim 6, wherein the control device further includes: an engine deceleration control section for inputting a deceleration command to the engine to cause the rotating engine shaft to begin decelerating; a first release control section for sending a disconnection command to the first clutch to switch from the power transmission state to the power cut-off state when the deceleration command is input to the engine; and a regenerative power generation control section for controlling the electrical system so that generated power is supplied from the stator coil when the deceleration command is input to the engine.

12. The underwater vehicle engine system according to claim 11, wherein the power transmission device further includes a second clutch disposed between the output shaft and a propeller shaft of the propeller, and the control device is configured to maintain the second clutch in the power transmission state until the rotating propeller starts to decelerate and then stops.

13. The underwater vehicle engine system according to claim 12, wherein the electrical system includes a battery, and the regenerative power generation control unit is configured to control the electrical system so that the generated power is supplied from the stator coil to the battery.

14. The aircraft engine system according to claim 8, wherein the power generation control unit is configured to control the electrical system so that the generated power is supplied from the stator coil to a load in the electrical system.

15. The underwater vehicle engine system according to claim 8, wherein the electrical system includes a battery, and the power generation control unit is configured to control the electrical system so that the generated power is supplied from the stator coil to the battery.

16. The underwater vehicle engine system of claim 6, further comprising at least one of a propeller tachometer for measuring the propeller rotation speed of the propeller or an engine tachometer for measuring the engine rotation speed of the engine, wherein the control device includes: a stop determination unit for determining whether the underwater vehicle has come to a stop based on at least one of the propeller tachometer or the engine tachometer; a clutch switching control unit configured to, when it is determined that the underwater vehicle has come to the stop state, send a decoupling command to the second clutch to switch from the power transmission state to the power cut-off state and send the operation command to the first clutch; and an anchorage power generation control unit for controlling the electrical system so that generated power is supplied from the stator coil after control is executed by the clutch switching control unit.

17. The underwater vehicle engine system of claim 5, wherein the control device further includes: a first motoring control unit for controlling the electrical system so that a first electric power for rotating the propeller in a first direction is supplied from the electrical system to the stator coil; and a second motoring control unit for controlling the electrical system so that a second electric power for rotating the propeller in a second direction is supplied from the electrical system to the stator coil.

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