JP7405705B2 - ship - Google Patents

Description

The present invention relates to a ship equipped with a contra-rotating marine propeller.

A counter-rotating propeller is a propeller in which two propellers are arranged coaxially in front and behind each other and rotate in opposite directions. Counter-rotating propellers are mainly used in aircraft because they can offset counter torque and have excellent propulsion efficiency because they can use the swirling flow behind the propeller in the front to propel the rear propeller.

On the other hand, the application of counter-rotating propellers to ships has not progressed as much as to aircraft. The main reason for this is that the drive mechanism tends to be complicated and there are problems with mechanical reliability.
For example, in a known counter-rotating propeller, a hollow drive shaft that drives one propeller is provided around a drive shaft that drives the other propeller (Patent Document 1). In such a structure, the structure around the drive shaft becomes complicated and there are problems in terms of maintenance and management. In addition, since one drive shaft is placed inside the other hollow shaft, if a problem such as eccentricity or deflection occurs in either drive shaft, the two drive shafts will come into contact with each other and both propellers will fail at the same time. There is a risk that Therefore, when used in ships such as ocean-going ships, where there is a high possibility of drifting or being lost if the propeller fails, additional measures must be taken in terms of redundancy.

On the other hand, there are counter-rotating propellers that improve reliability by separating the power transmission mechanisms of the two propellers to ensure redundancy. For example, there is a structure in which a sub-propeller at the rear in the ship's length direction is provided as a pod propulsion device at the rear of the main propeller (Patent Document 2). There is also a structure in which a sub-propeller at the rear in the vessel length direction is provided on a rudder valve of a fixed rudder plate, and the sub-propeller is driven by a motor inside the rudder valve (Patent Document 3).

Japanese Patent Application Publication No. 2004-168222 Japanese Patent Application Publication No. 2011-025816 Japanese Patent Application Publication No. 2014-019199

The structures of Patent Documents 2 and 3 have excellent redundancy in that the power transmission mechanisms of the two propellers are separated, and even if one propeller fails and does not operate, navigation is possible using the other propeller.
However, in Patent Documents 2 and 3, if the thrust of the rear propeller is made to be the same as that of other propellers driven by the main engine, a large motor that is difficult to mount on a conventional pod or fixed rudder is required.
Therefore, the pod that houses the motor and the rudder also need to be larger, and a reinforcing structure is required to cope with the increased weight that comes with the larger size, making the structure more complex.
Therefore, even if the power transmission mechanism is separated to ensure redundancy, the structure ends up becoming more complicated to accommodate the larger motor, resulting in a structure that poses problems in terms of maintenance and management. Additionally, if there was no space to install a larger motor, a counter-rotating propeller could not be used.
The present invention has been made in view of the above problems, and an object thereof is to provide a counter-rotating propeller that has a simpler structure and superior reliability than conventional propellers.

The ship of the present invention includes a main propeller that is rotatably provided at the stern of the ship about an axis facing the ship's ship's ship's ship's ship's ship's ship's ship's ship's ship's stern direction, and to which the power of the main engine is transmitted; A ship equipped with a counter-rotating propeller for a ship, including a sub-propeller that rotates in the opposite direction to the main propeller, the sub-propeller being driven by an electric motor in a rudder valve of a movable rudder disposed behind the main propeller in the ship's direction. and a sub-propeller boss having an outer shape constituting the front end in the longitudinal direction of the rudder valve, and protruding in the radial direction of the sub-propeller boss, and having a diameter of 50% or more and 70% or less of the diameter of the propeller blade of the main propeller. It is equipped with a sub-propeller blade , is connected to the power shaft of the main engine, and when power is transmitted from the power shaft, it regenerates and generates electricity to drive the electric motor, and when the power is supplied, it starts powering. a regenerative motor that assists in driving the main engine by transmitting power to the power shaft; and an inboard generator that is a driving power source for inboard equipment other than the main engine and that supplies power to the electric motor and the regenerative motor. , a ship comprising the main engine, the regenerative motor, and a control unit that controls driving of the inboard generator, wherein the control unit regeneratively drives the regenerative motor with the power of the main engine, and uses only regenerative electric power. a low-speed sailing mode in which the electric motor is driven; and a high-speed/rough weather sailing mode in which the regenerative motor is powered by the power of the inboard generator to assist in driving the main engine, and the electric motor is driven by the power of the inboard generator. It is characterized in that one of the navigation modes is selected depending on the magnitude of the output necessary for navigation, and control is performed to drive the auxiliary propeller .

In this configuration, the auxiliary propeller of the counter-rotating propeller is made smaller in diameter and integrated with the rudder valve of the movable rudder, and by turning with steering, a part of the swirling flow downstream of the propeller of the main propeller is generated without affecting the steering. This increases the propulsion efficiency by using it as a rudder valve.
In other words, the auxiliary propeller is not one of the propellers in a counter-rotating propeller, but rather an auxiliary propeller that conditionally rotates in the opposite direction to assist the main propeller, unlike a conventional counter-rotating propeller that generates the same amount of thrust with two propellers. It has a completely different structure and function.
Therefore, the counter-rotating propeller of the present invention does not need to increase the size of the motor that drives the auxiliary propeller, can be easily applied to ships equipped with conventional rudder valves, and has a simple structure and excellent reliability.

According to the present invention, it is possible to provide a counter-rotating propeller that has a simpler structure and superior reliability than conventional propellers.

FIG. 1 is a side sectional view of the stern and the vicinity showing an outline of the ship according to the present embodiment. FIG. 2 is a functional block diagram of FIG. 1, in which solid lines indicate power lines and broken lines indicate signal lines. 2 is an enlarged view of the vicinity of the contra-rotating propeller in FIG. 1. FIG. In FIG. 1, it is a diagram showing the supply of electric power during a low-speed navigation mode. FIG. 2 is a diagram illustrating the supply of electric power during a medium-speed navigation mode in FIG. 1 . FIG. 2 is a diagram illustrating power supply during high-speed/rough weather navigation mode in FIG. 1 . FIG. 2 is a flow diagram showing a method for navigating a ship according to the present embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.
First, the configuration of a ship 1 according to this embodiment will be explained with reference to FIGS. 1 to 3.
As shown in FIGS. 1 to 3, the ship 1 includes a hull 5, a rudder 31, a main engine 6, a counter-rotating propeller 3, an electric motor 17, a regenerative motor 11, an inboard generator 13, a switching circuit 15, and a control section 61. .

The hull 5 is a structure serving as the hull of the ship 1, and is configured to surround the inside of the ship with a bottom, side walls, and an exposed deck. The specific hull shape, hull structure, arrangement of watertight bulkheads, etc. are appropriately designed depending on the purpose of the ship 1. For example, in FIG. 1, a transom stern is illustrated as the stern structure, but a cruiser stern or a counterstern may also be used.

The rudder 31 is an underwater board that rotates about the Z direction, which is a vertical direction, when changing the course of the ship 1 . In FIG. 1, a so-called mariner type structure is illustrated as the rudder 31, but a hanging rudder type or a high-lift rudder may also be used. The rudder 31 includes a fixed rudder 33, a movable rudder 35, and a rudder valve 37.

The fixed rudder 33 is a member that fixes other members constituting the rudder 31 to the hull 5, and is a member that does not rotate. In the case of the Mariner type, the fixed rudder 33 is also called a rudder horn. The fixed rudder 33 in FIG. 1 is a plate-like member that projects downward from the stern bottom of the hull 5, and the side surface, which is the main surface of the plate, is parallel to the vertical Z direction and the ship's length direction, which is the X direction. .
The fixed rudder 33 includes fixed parts 33a and 33b that protrude from the stern end toward the stern. The fixed parts 33a and 33b are plate-shaped members that rotatably hold the movable rudder 35, and the rudder stock 36, which is a rotation shaft, is inserted through the fixed part 33a in the Z direction.

The movable rudder 35 is a plate-shaped member that is provided at the rear end of the fixed rudder 33 in the bow and stern direction and is rotatable about the axis of the rudder stock 36.
An insertion plate part 35a is provided at the front end of the upper end of the movable rudder 35 in the bow direction to be inserted between the fixed part 33a and the fixed part 33b, and the rudder stock 36 is inserted through the insertion plate part 35a and connected to the fixed part 33a. be done. The fixed part 33b is connected to the insertion plate part 35a by a pintle (not shown) so that the movable rudder 35 can rotate about the Z direction as a central axis.
The movable rudder 35 rotates as the power of the rudder stock 36 is transmitted.
The rudder valve 37 is a bulge protruding from both side surfaces and the front end of the movable rudder 35, and has a spindle-shaped outer shape when viewed from the side in FIG. 1, that is, from the Y direction, which is the width direction of the ship. Specifically, the rudder valve 37 has a cylindrical shape extending in the X direction, which is the ship's ship direction, and has a tapered shape at both ends. The rudder valve 37 is circular when viewed from the X direction. The rudder valve 37 is provided to reduce the flow rate of water flowing into the counter-rotating propeller 3 to improve propulsion efficiency. The outer shape and dimensions of the rudder valve 37 are set within a range that can improve propulsion efficiency and does not interfere with steering.

The main engine 6 is an engine that generates propulsive force for the ship 1, and in FIG. 1, it is an engine that drives at least one of the counter-rotating propellers 3.
Although the main engine 6 is a diesel engine located near the stern in FIG. 1, it may be a steam turbine as long as it can drive at least one of the counter-rotating propellers 3.
The main engine 6 in FIG. 1 has two power shafts, and has a structure in which power can be extracted from two places. Specifically, the main engine 6 includes a main propeller shaft 21 provided at the end on the stern side and a main motor shaft 25 provided at the end on the bow side. The main propeller shaft 21 and the main motor shaft 25 have a structure in which power is transmitted to each other.

The counter-rotating propeller 3 is a propulsion device that propels the ship 1 by rotating. The counter-rotating propeller 3 includes a main propeller 7 and a sub-propeller 9.

The electric motor 17 is a motor that drives the auxiliary propeller 9 in the ship 1, and is disposed within the rudder valve 37. As shown in FIG. 3, an electric motor shaft 17a, which is a drive shaft of the electric motor 17, is provided to protrude toward the bow side in the X direction, which is the ship's ship direction. The rating of the electric motor 17 is set according to the output of the counter-rotating propeller 3. As the drive method for the electric motor 17, any known method can be used as appropriate as long as it can drive the auxiliary propeller 9. However, in consideration of ease of controlling the rotation speed and efficiency, a synchronous motor is preferable, and a permanent magnet synchronous motor (PM) is preferable. Permanent magnet (synchronous motor) is more preferable.

The regenerative motor 11 is a motor that regenerates power when the power of the main engine 6 is transmitted, and assists the drive of the main engine 6 by running with power when the power is supplied.
The regenerative motor 11 is connected to the main engine 6 via the main engine motor shaft 25, which is the power shaft of the main engine 6, and gears 27, 29. When the main engine 6 is driven in the absence of power supply, the power of the main engine 6 is transferred to the main engine 6. The power is transmitted via the motor shaft 25 and gears 27 and 29 to generate regenerative power. The generated electric power is supplied to the electric motor 17 to drive the electric motor 17. When the regenerative motor 11 is powered, it transmits power to the main engine motor shaft 25 via the gears 27 and 29 to assist in driving the main engine 6.
As the regenerative motor 11, a known drive system can be used as appropriate as long as it is capable of regeneration and power running and can assist in driving the main engine 6, but like the electric motor 17, a synchronous motor is preferable, and a PM synchronous motor is more preferable.

The inboard generator 13 is a generator that generates electric power for driving the inboard devices 23 in the ship 1 other than the counter-rotating propeller 3, and can be exemplified by a diesel generator. Examples of the onboard equipment 23 include lighting and air conditioning inside the ship, or, if the ship 1 is a cargo ship, a crane fixed to the ship's hull 5 and used for loading/unloading cargo.
However, the inboard generator 13 of this embodiment is configured to use part of the electric power to supplement the propulsive force of the counter-rotating propeller 3. Therefore, the power line of the inboard generator 13 is connected to the electric motor 17 and may serve as a driving power source for the electric motor 17. Further, the power line of the inboard generator 13 is also connected to the regenerative motor 11, and may serve as a driving power source when the regenerative motor 11 runs under power.

The switching circuit 15 is an inverter device that adjusts the voltage and frequency when supplying electric power generated by the inboard generator 13 and regenerative motor 11 to the electric motor 17. The switching circuit 15 is also an inverter device that adjusts the voltage and frequency when supplying the electric power generated by the inboard generator 13 to the regenerative motor 11. The switching circuit 15 is provided in the middle of the power line connecting the inboard generator 13 or the regenerative motor 11 and the electric motor 17, and in the middle of the power line connecting the inboard generator 13 and the regenerative motor 11. As the switching circuit 15, a known inverter can be used as long as it can control the voltage and frequency of the electric power supplied to the electric motor 17 and the regenerative motor 11 within a desired range. For example, when the electric motor 17 and the regenerative motor 11 are PM synchronous motors, the switching circuit 15 uses a variable voltage variable frequency (VVVF) controlled inverter.

The main propeller 7 is a propeller to which the power of the main engine 6 is directly transmitted. Concatenated. As shown in FIG. 3, the main propeller 7 includes a main propeller boss 41 and main propeller blades 43.

The main propeller boss 41 is an outer cylindrical part of the main propeller 7, and the stern end of the main propeller shaft 21 is connected and fixed with a key (not shown) to transmit power, and rotates around the axis by the transmitted power. do.
The main propeller blades 43 are a plurality of blade-shaped plates protruding from the outer periphery of the main propeller boss 41 in the radial direction. The number and diameter D1 of the main propeller blades 43 are appropriately set according to the thrust required for the main propeller 7 and the installation space. Note that the "diameter of the main propeller blade 43" herein means twice the radial distance from the rotation center C of the main propeller shaft 21, which is the rotation axis, to the radial tip of the main propeller blade 43.

The auxiliary propeller 9 is a propeller that is arranged coaxially behind the main propeller 7 in the longitudinal direction and rotates in the opposite direction to the main propeller 7. The term "aft in the ship's direction" as used herein means that the auxiliary propeller 9 is located further from the bow than the main propeller 7 in the ship's ship direction.
The secondary propeller 9 improves propulsion efficiency by using the swirling flow after the propeller of the main propeller 7 as a propulsion force, and also counter-torques the rotation of the main propeller 7 by rotating in the opposite direction to the main propeller 7. It has a countervailing effect.
As shown in FIG. 3, the sub-propeller 9 includes a sub-propeller boss 51 and a sub-propeller blade 53.

The auxiliary propeller boss 51 is an outer cylindrical portion of the auxiliary propeller 9, and the end of the bow side of the electric motor shaft 17a, which is the drive shaft of the electric motor 17, is connected and fixed with a key (not shown) to transmit power. It rotates around its axis with the power generated.

In this structure, the main propeller shaft 21, which is the drive shaft of the main propeller 7, and the electric motor shaft 17a, which is the drive shaft of the auxiliary propeller 9, are separated from each other and are spaced apart from each other in the axial direction and face each other, but they are opposed to each other in the radial direction. do not. Therefore, the main propeller shaft 21 and the electric motor shaft 17a do not interfere with each other, so even if a problem such as eccentricity or deflection occurs in one, there is a low possibility that the main propeller 7 and the auxiliary propeller 9 will fail at the same time due to contact with the other.

Further, in this structure, the sub-propeller 9 is provided on the movable rudder 35. Providing the secondary propeller 9 on the fixed rudder 33 increases the size of the fixed rudder 33 and reduces the area of the movable rudder 35. However, in this structure, the secondary propeller 9 is integrated with the movable rudder 35, so the fixed rudder It is easy to secure the area of the movable rudder 35 without increasing the size of the rudder 33. Therefore, the auxiliary propeller 9 is unlikely to have an adverse effect on maneuverability such as turning performance.

Furthermore, as shown in FIG. 3, the sub-propeller boss 51 has an external shape that constitutes a part of the rudder valve 37. Specifically, the rudder valve 37 has a cylindrical shape extending in the X direction when viewed from the side, and has a tapered shape at both ends. The sub-propeller boss 51 in FIG. 3 constitutes the front end of the rudder valve 37 in the longitudinal direction, and therefore has a conical shape that tapers from the stern side to the bow side. The front end in the ship's ship direction means the end on the bow side in the ship's ship direction.
By making the sub-propeller boss 51 a part of the rudder valve 37 in this way, the sub-propeller 9 can also function as the rudder valve 37, which is even more advantageous in terms of propulsion efficiency.

The auxiliary propeller blades 53 are a plurality of blade-shaped plates that protrude from the outer periphery of the auxiliary propeller boss 51 in the radial direction. The number of sub-propeller blades 53 is appropriately set depending on the required propulsive force. However, the diameter D2 of the auxiliary propeller blade 53 is shorter than the diameter D1 of the main propeller blade 43 of the main propeller 7. The "diameter of the auxiliary propeller blade 53" herein means twice the radial distance from the rotation center C of the electric motor shaft 17a, which is the rotating shaft, to the tip of the auxiliary propeller blade 53.
The reason why the diameter D2 of the auxiliary propeller blade 53 is made shorter than the diameter D1 of the main propeller blade 43 of the main propeller 7 will be explained.

In order to avoid complicating the structure of the propulsion mechanism and reducing reliability due to the provision of the contra-rotating propeller 3, the ship 1 is provided with an auxiliary propeller 9 on the movable rudder 35, and driven by an electric motor 17 within the movable rudder 35. The drive shafts of the main propeller 7 and the sub-propeller 9 are separated.
On the other hand, in the conventional counter-rotating propeller 3, the diameters of the main propeller 7 and the sub-propeller 9 are approximately the same, and the propulsive force is also approximately the same. Therefore, in the structure of the ship 1, if the main propeller 7 and the sub-propeller 9 are made to have the same diameter and the same propulsive force, the electric motor 17 will become larger, and the rudder 31 will also become larger and heavier, which will support the weight of the rudder 31. The structure etc. to be used becomes complicated.
Although the structure in which the drive shafts of the main propeller 7 and the auxiliary propeller 9 are separated is well known, the reason why counter-rotating propellers are reluctant to be applied to existing ships is because the drive shafts are separated to ensure redundancy. This is because the problem of increasing the size of the device arises, and the structure becomes complicated.

In contrast, the present inventor considered that in a counter-rotating propeller for a ship, it is not necessary for two propellers to generate the same level of propulsive force. The reason is as follows. First of all, it is important for counter-rotating propellers for aircraft to offset counter torque. This is because an aircraft performs a roll motion when changing course, and unless counter torque is taken into consideration, the aircraft will always continue to roll in one direction, making it difficult to fix the course. On the other hand, for ships, the propulsion resistance due to water is much greater than that from air, so counter torque offset is not as important as for aircraft.

In addition, the contra-rotating propeller improves propulsion efficiency by recovering the energy of the swirling flow behind the main propeller 7, which is the propeller in the front of the propeller, by the auxiliary propeller 9, which is the propeller in the rear of the propeller. Therefore, even if the energy of the swirling flow is not completely recovered, propulsion efficiency can be increased even if only a portion of it is recovered.

Furthermore, if the electric motor 17 is provided inside the rudder valve 37 and the sub-propeller 9 has an external shape that acts as the rudder valve 37, the propulsion efficiency can be increased as the rudder valve 37 even if the energy of the swirling flow is not completely recovered. .
Further, if only a part of the energy of the swirling flow is recovered, it is not necessary to always arrange the sub-propeller 9 on the same axis as the main propeller 7, so the sub-propeller 9 is provided on the movable rudder 35 and the rudder 31 is It doesn't matter if it turns when cut. In this case, depending on the steering angle, the auxiliary propeller 9 may come into contact with the main propeller 7, but by increasing the distance between the main propeller 7 and the auxiliary propeller 9 in the axial direction, contact can be prevented.
Furthermore, if it is not necessary to always arrange the auxiliary propeller 9 on the same axis as the main propeller 7, a hollow drive shaft for driving one propeller is provided around the drive shaft for driving the other propeller, as in the prior art. There's no need. Therefore, the drive shafts of the main propeller 7 and the sub-propeller 9 can be separated to ensure redundancy.

Based on the above findings, the inventor of the present invention separated the drive shaft of the auxiliary propeller 9 from the main propeller 7, made it smaller in diameter, and integrated it with the rudder valve 37, thereby absorbing only a portion of the energy of the swirling flow downstream of the propeller. It was found that propulsion efficiency can be sufficiently increased even when recovering
It has been found that this makes it possible to increase propulsion efficiency without increasing the size of the electric motor 17, and to realize a counter-rotating propeller for ships that has a simpler structure and superior reliability than before.
Note that in this structure, the drive shafts of the main propeller 7 and the auxiliary propeller 9 are separated, so even if one propeller stops, the other propeller does not stop. In this respect, it has greater redundancy than conventional counter-rotating propellers in which a hollow drive shaft driving one propeller is arranged around a drive shaft driving the other propeller.
Furthermore, in this structure, the main propeller 7 bears most of the thrust, and the ship 1 can sail normally with just the thrust of the main propeller 7, but the main propeller 7 is not a counter-rotating propeller. It can have the same structure as the propeller of a known single-shaft ship. In this case, the possibility that normal navigation will become impossible due to a malfunction is extremely low, as is the case with known single-shaft ships.
The above is an explanation of the reason why the diameter D2 of the auxiliary propeller blade 53 is made shorter than the diameter D1 of the main propeller blade 43 of the main propeller 7.

However, if the diameter D2 is less than 50% of the diameter D1, the energy of the swirling flow that can be recovered by the auxiliary propeller 9 will be significantly reduced, and the effect of improving the propulsion efficiency will not be obtained. Therefore, the diameter D2 of the auxiliary propeller blade 53 is set to be 50% or more of the diameter D1 of the main propeller blade 43 of the main propeller 7. From the viewpoint of ensuring recoverable energy, the diameter D2 is preferably at least 55% of the diameter D1, more preferably at least 58%.

Furthermore, if the diameter D2 exceeds 70% of the diameter D1, the electric motor 17 that is large enough to be housed in the rudder valve 37 will not have enough power to rotate the secondary propeller blades 53, so the propulsion efficiency will improve even though the weight increases. It disappears.
Therefore, the diameter D2 of the auxiliary propeller blade 53 is set to 70% or less of the diameter D1 of the main propeller blade 43.
Further, from the viewpoint of suppressing an increase in the weight of the auxiliary propeller 9, the diameter D2 is preferably 65% or less of the diameter D1, and more preferably 62% or less.

In this way, the contra-rotating propeller 3 has the sub-propeller blade 53 reduced in diameter, is integrated with the rudder valve 37 of the movable rudder 35, and is independently driven by the electric motor 17 within the rudder valve 37.
In this configuration, the auxiliary propeller 9 of the counter-rotating propeller 3 is made smaller in diameter and integrated with the rudder valve 37 of the movable rudder 35, so that it rotates with the steering so that it is part of the swirling flow of the main propeller 7 without affecting the steering. The rudder valve 37 increases the propulsion efficiency.
In other words, the auxiliary propeller 9 is not one of the propellers of the counter-rotating propeller 3, but rather an auxiliary propeller that rotates in the opposite direction conditionally to assist the main propeller 7.
Therefore, the counter-rotating propeller 3 has a simpler structure and superior reliability than the conventional propeller.

As shown in FIG. 3, the secondary propeller blades 53 are preferably swept-back blades. The swept wing here means a wing shape in which the protruding direction faces not only the radial direction but also the rear in the longitudinal direction.
By making the auxiliary propeller blade 53 a swept blade, when the rudder 31 is turned, the auxiliary propeller blade 53 does not come into contact with the main propeller blade 43 if the rudder angle is within the swept angle. Furthermore, the axial separation distance between the main propeller boss 41 and the auxiliary propeller boss 51 can be shortened while maintaining the distance between the auxiliary propeller blade 53 and the main propeller blade 43 compared to the case where the auxiliary propeller blade 53 is not a swept-back blade.

Here, the swept angle of the swept blades is an acute angle α of the angles formed by the sub propeller blades 53 with respect to an imaginary line L parallel to the radial direction of the electric motor shaft 17a, as shown in FIG. It is preferable that the sweepback angle is greater than or equal to the maximum rudder angle required by the vessel 1. Thereby, when the rudder 31 is turned, it is possible to secure a rudder angle at which the auxiliary propeller blade 53 does not come into contact with the main propeller blade 43.

The output of the electric motor 17 may be smaller than the output of the main engine 6 since the sub propeller 9 only needs to be able to recover a part of the swirling flow of the main propeller 7. Therefore, the output burden rate of the sub-propeller 9 may be less than 50%. The output load rate here is the value obtained by dividing the output of the electric motor 17 by the sum of the output of the main engine 6 and the output of the electric motor 17, multiplied by 100.
The output burden rate commensurate with the reduction in the diameter of the secondary propeller 9 is preferably 25% or less, more preferably 22% or less.
In addition, in order to fully obtain the effect of improving propulsion efficiency by providing the sub-propeller 9, the output load ratio is preferably 5% or more, more preferably 8% or more.

The output burden rate of the electric motor 17 may vary depending on the ship speed.
For example, the rating of the electric motor 17 may be set to a value corresponding to the output load rate at a predetermined speed less than the maximum speed of the ship 1.
Specifically, the rating may be such that the output burden rate at a predetermined ship speed V below the maximum ship speed is 5% or more and 25% or less. In this case, when the ship 1 travels at a speed exceeding the ship speed V, a larger output is required for propulsion, but the electric motor 17 cannot output more than the rated output. Therefore, at a boat speed exceeding the boat speed V, the output of the electric motor 17 is fixed at the rated value, and the insufficient output is compensated for by increasing the output of the main propeller 7 side. Therefore, at a ship speed exceeding ship speed V, the output burden rate of the electric motor 17 decreases as the ship speed increases.

In this way, when the output of the electric motor 17 based on the output load rate is equal to or higher than the rated value, the electric motor 17 is driven at the rated value, and by increasing the output load rate of the main engine 6, the electric motor 17 can be downsized without greatly reducing the propulsion efficiency.

As shown in FIG. 2, the control unit 61 is a computer that controls the operations of the main engine 6, the electric motor 17, the switching circuit 15, and the inboard generator 13, and is electrically connected to the main engine 6 and the switching circuit 15.
Specifically, the control unit 61 selects one of three navigation modes: a low-speed navigation mode, a medium-speed navigation mode, and a high-speed navigation mode, depending on the magnitude of the output required for navigation of the ship 1. control the navigation. The three navigation modes will be explained below.

The low-speed navigation mode is a navigation mode used in an output range where the output required for navigation is the smallest, and specifically used during low-speed navigation on a clear day. As shown in FIG. 4, in the low-speed navigation mode, the regenerative motor 11 is regeneratively driven by the power of the main engine 6, and the electric motor 17 is driven only by the regenerated power. Specifically, the control unit 61 does not supply driving power to the regenerative motor 11 , but controls a clutch (not shown) or the like so that the power of the main engine 6 is transmitted to the regenerative motor 11 via the main engine motor shaft 25 , and controls the gear 27 . , 29 connect the main engine motor shaft 25 and the regenerative motor 11.

In this state, the regenerative motor 11 does not power because there is no power supply, but performs regenerative power generation using the power of the main engine 6, and transmits the generated power to the switching circuit 15. Under the control of the control unit 61, the switching circuit 15 converts the transmitted power into a frequency and voltage necessary for driving the electric motor 17, supplies the converted electric power to the electric motor 17, and rotates the auxiliary propeller 9.
Note that the main propeller 7 is rotated by the driving force transmitted to the main engine 6 via the main propeller shaft 21. The output of the main engine 6 is controlled by a control section 61.
In the low-speed navigation mode, the main engine 6 also serves as the power source for the main propeller 7 and the auxiliary propeller 9. Therefore, it is advantageous for low-speed navigation that does not require high power.

Medium-speed sailing mode is a sailing mode used when higher output is required than slow-speed sailing mode. Specifically, it is faster than slow-speed sailing mode, but sails at a much slower speed than the maximum ship speed on clear skies. It is in navigation mode.
As shown in FIG. 5, the medium-speed cruise mode is the same as the low-speed cruise mode in that the regenerative motor 11 is regeneratively driven by the power of the main engine 6. However, this differs from the low-speed cruise mode in that not only the regenerated power but also the power of the inboard generator 13 is used to drive the electric motor 17.

Specifically, the control unit 61 does not supply drive power to the regenerative motor 11 as in the low-speed cruise mode, causes the main engine 6 to generate regenerative power, and transmits the generated power to the switching circuit 15. Furthermore, the control unit 61 causes a part of the electric power from the inboard generator 13 to be transmitted to the switching circuit 15 . Under the control of the control unit 61, the switching circuit 15 converts the transmitted power into power having a frequency and voltage necessary for driving the electric motor 17, supplies the converted electric power to the electric motor 17, and rotates the auxiliary propeller 9.
Note that the main propeller 7 is rotated by the driving force transmitted to the main engine 6 via the main propeller shaft 21 similarly to the low-speed cruise mode. The output of the main engine 6 is controlled by a control section 61.
In the medium-speed navigation mode, not only the main engine 6 but also the inboard generator 13 are used as the power source for the auxiliary propeller 9. Therefore, it is more advantageous in navigation that requires high power than in low-speed navigation mode.

The high-speed/rough weather navigation mode is a navigation mode when the highest output is required when the ship 1 is navigating, and specifically, it is a navigation mode when the ship 1 is navigating near the maximum speed or in rough weather.
As shown in FIG. 6, in the high speed/rough weather navigation mode, the regenerative motor 11 is powered by the power of the inboard generator 13 to assist in driving the main engine 6, and the electric motor 17 is driven by the power of the inboard generator 13.
Specifically, the control unit 61 transmits a portion of the electric power of the inboard generator 13 to the switching circuit 15, and further controls the switching circuit 15 to send a portion of the electric power of the inboard generator 13 to the electric motor 17 and the regenerative motor. 11 is supplied. The switching circuit 15 converts a part of the electric power supplied from the inboard generator 13 into electric power with a frequency and voltage necessary for driving the electric motor 17 and supplies the converted electric power to the electric motor 17 to rotate the auxiliary propeller 9. Further, a part of the electric power supplied from the inboard generator 13 is converted into electric power having a frequency and voltage necessary for powering the regenerative motor 11, and is supplied to the regenerative motor 11, thereby causing the regenerative motor 11 to power. The powered regenerative motor 11 rotates the main engine motor shaft 25 via the gears 27 and 29, thereby transmitting power to the main propeller shaft 21 and assisting the main engine 6 to drive the main propeller 7. Note that in the high speed/rough weather navigation mode, the main engine 6 does not drive the electric motor 17, but only drives the main propeller 7.

In the high-speed/rough weather navigation mode, only the inboard generator 13 is used as a power source for the auxiliary propeller 9. Further, the regenerative motor 11 is used to assist in driving the main propeller 7. Therefore, the output of the main propeller 7 and the auxiliary propeller 9 is the largest compared to other navigation modes. Therefore, it is more advantageous in navigation that requires higher power than the medium-speed navigation mode.

The control unit 61 controls driving the sub propeller 9 by selecting one of the three navigation modes depending on the magnitude of the output. Specifically, first, the output range from the minimum value to the maximum value of the output necessary for navigation of the ship 1 is divided into three parts and stored in advance in a storage part (not shown) of the control part 61. Next, the control unit 61 refers to the storage unit when the ship 1 is navigating, and selects the low-speed navigation mode when the output required for navigation is in the minimum output range, and selects the medium-speed navigation mode when the output required for navigation is in the second smallest output range. and select high speed/rough weather navigation mode for the largest power range.
In this configuration, in the output range where the output required during navigation is minimum, the sub-propeller 9 is driven only by the regenerative power obtained by the main engine 6 driving the regenerative motor 11 in the low-speed navigation mode. In the second smallest output range, the power of the inboard generator 13 is also used to drive the auxiliary propeller 9 in medium speed navigation mode. In the largest output range, the inboard generator 13 powers the regenerative motor 11 to assist the main engine 6 in high speed/rough weather navigation mode.

In this way, by using the inboard generator 13 and the regenerative motor 11 as a power source for navigation according to the output required for navigation, the thrust necessary for navigation can be maintained even when the auxiliary propeller 9 is downsized. Furthermore, since the inboard generator 13 supplies part of the electric power necessary for navigation, the main engine 6 can be made smaller.

The navigation mode may be selected with reference to the ship speed, wave height, and wind speed.
For example, the control unit 61 determines the speed ranges in which the ship 1 can navigate in three speed ranges corresponding to the three navigation modes, that is, three power ranges, and sets the ship speed of the ship 1 in descending order of low speed range, medium speed range, and high speed range. The speed range can be divided into three speed ranges. In this case, if the ship speed during navigation is in the low speed range, select the low speed sailing mode, if the ship speed is in the medium speed range, select the medium speed sailing mode, and if the ship speed is in the high speed range, select the high speed/rough weather sailing mode. . The ship speed may be actually measured, or the target ship speed set by the control unit 61 may be used as the ship speed.
However, if you select a navigation mode based only on the ship's speed, the resistance from waves will increase, such as during rough weather, and there is a possibility that the output will be insufficient when high output is required even at low speeds.
Therefore, when the weather is rough, specifically when the wave height and wind speed exceed predetermined values, it is preferable to select the high speed/rough weather navigation mode regardless of the ship speed. Wave height and wind speed may be measured, or information may be obtained from a weather observatory.
In this configuration, the faster the boat speed is, the higher the output is selected, and in the case of rough weather, the sailing mode is selected that provides the maximum output regardless of the boat speed.
Therefore, it is possible to select the optimal navigation mode that maintains the necessary and sufficient output for navigation depending on the ship's speed and weather conditions.

There does not necessarily have to be three navigation modes. Two is fine. For example, the control unit 61 may prepare only two navigation modes, a low-speed navigation mode and a high-speed/rough weather navigation mode, and select one of the navigation modes depending on the magnitude of the output required for navigation.
Specifically, the control unit 61 selects the low-speed navigation mode when the output required for navigation of the vessel 1 is below a predetermined boundary output, and selects the high-speed/rough weather navigation mode when the output exceeds the boundary output. Good too.
Alternatively, the control unit 61 may select the low-speed navigation mode when the speed of the ship 1 is less than or equal to a predetermined boundary speed, and select the high-speed/rough weather navigation mode when the speed exceeds the threshold speed. In this case, if the wave height and wind speed exceed predetermined values, the high speed/rough weather navigation mode may be selected regardless of the ship speed.

Even in the same navigation mode, the control unit 61 may increase the power supplied to the electric motor 17 as the required output increases.
Specifically, the power supplied to the electric motor 17 may be increased as the boat speed increases in the same navigation mode. The reason is as follows.
For example, if the ship continues to sail with the same power in the same low-speed sailing mode, there is a possibility that the ship's power will be insufficient at a ship speed near the boundary with the medium-speed sailing mode. In order to avoid insufficient power, if the output in low-speed navigation mode is fixed to the output corresponding to the ship speed near the boundary with medium-speed navigation mode, the output will be excessive at ship speeds slower than the boundary with medium-speed navigation mode. becomes.
In such a case, even in the same sailing mode, as the ship speed increases, the power required to drive the sub-propeller 9 increases, thereby reducing the output required to drive the sub-propeller 9 when the ship speed is near the boundary between different sailing modes. It can prevent shortages and excesses.

Note that the control unit 61 may rotate the auxiliary propeller 9 only during navigation in a low speed range. Specifically, power is supplied from the regenerative motor 11 or the inboard generator 13 to the electric motor 17 only when the ship speed is below a predetermined lower limit ship speed and the wave height and wind speed do not exceed predetermined values. However, it is not necessary to supply power in the medium speed range, high speed range, or in stormy weather. The lower limit ship speed is, for example, the upper limit of ship speed in a low speed range. The case where the wave height and wind speed do not exceed predetermined values is the case when the weather is not stormy.
In this case, only the main propeller 7 is driven in the medium-speed range, high-speed range, and in rough weather, and the sub-propeller 9 only functions as the rudder valve 37, so the propulsive efficiency improvement effect as a counter-rotating propeller is less effective in the low-speed range. Can only be obtained while sailing. However, the power sources and power transmission mechanisms such as the electric motor 17, the main engine 6, and the inboard generator 13 can be downsized. Further, since only one of the regenerative motor 11 and the inboard generator 13 needs to be the power source for the electric motor 17, the power transmission mechanism and the power transmission mechanism can be simplified, and mechanical reliability is also improved. Therefore, it is advantageous for ships that mainly navigate in low-speed navigation mode. Note that when the sub-propeller 9 is rotated only during navigation in a low-speed range, the power supply that supplies power to the sub-propeller 9 may be the inboard generator 13 instead of the regenerative motor 11.

As described above, the sub-propeller 9 in this embodiment may not rotate depending on the navigation conditions. Therefore, the auxiliary propeller 9 is an auxiliary propeller that conditionally rotates in the opposite direction to assist the main propeller 7, rather than one side of a counter-rotating propeller. From this point as well, it can be seen that the counter-rotating propeller 3 of this embodiment has a completely different structure from a conventional counter-rotating propeller in which two propellers have an equivalent structure.
The above is the description of the structure of the ship 1 including the counter-rotating propeller 3 in this embodiment.

Next, an example of the navigation procedure of the ship 1 according to the present embodiment will be explained with reference to FIG.
First, the control unit 61 acquires the wave height, wind speed, and ship speed when the ship 1 is sailing (S1 in FIG. 7).
Next, the control unit 61 determines whether or not it is stormy weather based on the wave height and wind speed, and if it is not stormy weather, the process proceeds to S3, and if it is stormy weather, the process proceeds to S4 (S2 in FIG. 7). Specifically, the relationship between wave height and wind speed and the output necessary for navigation is determined in advance and stored in the control unit 61, and in the case of wave height and wind speed that require the output required for navigation in high-speed/rough weather navigation mode. It can be determined that the weather is stormy.

If it is determined in S3 that the weather is not rough, the control unit 61 determines which of the three ship speed ranges the ship speed belongs to. In the case of a high speed range, the process proceeds to S4, in the case of a medium speed area, the process proceeds to S5, and in the case of a low speed area, the process proceeds to S6 (S3 in FIG. 7).
If it is determined in S2 that the weather is rough, and if it is determined that the ship speed is in the high speed range in S3, the control unit 61 selects the high speed/rough weather navigation mode and navigates the ship 1 (S4 in FIG. 7).
If it is determined in S3 that the ship speed is in the medium speed range, the control unit 61 selects the medium speed navigation mode and navigates the ship 1 (S5 in FIG. 7).
If it is determined in S3 that the ship speed is in the low speed range, the control unit 61 selects the low speed navigation mode and navigates the ship 1 (S6 in FIG. 7).
The above is an explanation of an example of the navigation procedure of the ship 1 according to the present embodiment.

In this way, the present embodiment reduces the diameter of the auxiliary propeller 9 of the counter-rotating propeller 3 and integrates it with the rudder valve 37 of the movable rudder 35 to allow turning during steering while also controlling part of the swirling flow of the main propeller 7. The rudder valve 37 increases the propulsion efficiency.
Therefore, there is no need to increase the size of the electric motor 17 that drives the auxiliary propeller 9, and the present invention can be easily applied to a ship equipped with a conventional rudder valve, and has a simple structure and excellent reliability.

Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the embodiments. It is natural for those skilled in the art to come up with various modifications and improvements within the scope of the technical idea of the present invention, and these are also included in the present invention.

1: Ship 3: Counter-rotating propeller 5: Hull 6: Main engine 7: Main propeller 9: Sub-propeller 11: Regenerative motor 13: Inboard generator 15: Switching circuit 17: Electric motor 17a: Electric motor shaft 21: Main propeller shaft 23: Inboard equipment 25: Main engine motor shaft 27, 29: Gear 31: Rudder 33: Fixed rudder 33a, 33b: Fixed part 35: Movable rudder 35a: Insertion plate part 36: Rudder stock 37: Rudder valve 41: Main propeller boss 43 : Main propeller blade 51 : Sub-propeller boss 53 : Sub-propeller blade 61 : Control section

Claims (8)

A main propeller, which is rotatably provided at the stern of the ship around an axis facing the ship's ship's ship's direction, and to which the power of the main engine is transmitted; and a main propeller, which is placed coaxially behind the main propeller in the ship's ship's direction and rotates in the opposite direction to the main propeller. A ship equipped with a counter-rotating propeller for ships equipped with an auxiliary propeller,
The auxiliary propeller is driven by an electric motor in a rudder valve of a movable rudder disposed rearward in the longitudinal direction of the main propeller, and has a auxiliary propeller boss having an external shape that constitutes a front end in the longitudinal direction of the rudder valve, and A sub-propeller blade is provided that protrudes in the radial direction and has a diameter of 50% or more and 70% or less of the diameter of the propeller blade of the main propeller,
It is connected to the power shaft of the main engine, and when power is transmitted from the power shaft, it regenerates and generates electricity to drive the electric motor, and when power is supplied, it runs and transmits power to the power shaft. a regenerative motor that assists in driving the main engine;
an inboard generator that is a driving power source for inboard equipment other than the main engine and supplies power to the electric motor and the regenerative motor;
A ship comprising the main engine, the regenerative motor, and a control unit that controls driving of the inboard generator,
The control unit includes:
a low-speed navigation mode in which the regenerative motor is regeneratively driven by the power of the main engine and the electric motor is driven only with the regenerated power;
Sailing in any one of a high-speed sailing mode and a rough-weather sailing mode in which the regenerative motor is powered by the power of the inboard generator to assist in driving the main engine, and the electric motor is driven by the power of the inboard generator. 1. A ship characterized in that the auxiliary propeller is controlled to be selectively driven depending on the magnitude of the output required for the auxiliary propeller. The control unit includes:
The vessel according to claim 1, wherein the low-speed navigation mode is selected when the output required for navigation of the vessel is below a predetermined boundary output, and the high-speed/rough weather navigation mode is selected when the output exceeds the boundary output. . The control unit includes:
Selecting the low-speed navigation mode when the ship speed of the ship is below a predetermined boundary ship speed, and selecting the high-speed/rough weather navigation mode when the ship speed exceeds the boundary ship speed,
The ship according to claim 1, wherein the high speed/rough weather navigation mode is selected regardless of ship speed when wave height and wind speed exceed predetermined values. A main propeller, which is rotatably provided at the stern of the ship around an axis facing the ship's ship's ship's direction, and to which the power of the main engine is transmitted; and a main propeller, which is placed coaxially behind the main propeller in the ship's ship's direction and rotates in the opposite direction to the main propeller. A ship equipped with a counter-rotating propeller for ships equipped with an auxiliary propeller,
The auxiliary propeller is driven by an electric motor in a rudder valve of a movable rudder disposed rearward in the longitudinal direction of the main propeller, and has a auxiliary propeller boss having an external shape that constitutes a front end in the longitudinal direction of the rudder valve, and A sub-propeller blade is provided that protrudes in the radial direction and has a diameter of 50% or more and 70% or less of the diameter of the propeller blade of the main propeller,
It is connected to the power shaft of the main engine, and when power is transmitted from the power shaft, it regenerates and generates electricity to drive the electric motor, and when power is supplied, it runs and transmits power to the power shaft. a regenerative motor that assists in driving the main engine;
an inboard generator that is a driving power source for inboard equipment other than the main engine and supplies power to the electric motor and the regenerative motor;
A ship comprising the main engine, the regenerative motor, and a control unit that controls driving of the inboard generator,
The control unit includes:
a low-speed navigation mode in which the regenerative motor is regeneratively driven by the power of the main engine and the electric motor is driven only with the regenerated power;
a medium-speed navigation mode in which the regenerative motor is regeneratively driven by the power of the main engine, and the electric motor is driven by the regenerative power and the power of the inboard generator;
Sailing in any one of a high-speed sailing mode and a rough-weather sailing mode in which the regenerative motor is powered by the power of the inboard generator to assist in driving the main engine, and the electric motor is driven by the power of the inboard generator. 1. A ship characterized in that the auxiliary propeller is controlled to be selectively driven depending on the magnitude of the output required for the auxiliary propeller. The control unit includes:
The output range from the minimum value to the maximum value of the output required for navigation of the vessel is divided into three, and the low speed navigation mode is selected when the output required by the vessel during navigation is in the minimum output range. 5. The ship according to claim 4 , wherein the medium-speed sailing mode is selected in the case of the second smallest power range, and the high-speed/rough weather sailing mode is selected in the case of the largest power range. The control unit includes:
The speed of the ship is divided into three speed ranges: a low speed range, a medium speed range, and a high speed range, in descending order of speed,
Selecting the low speed navigation mode when the ship speed is in the low speed range, selecting the medium speed sailing mode when the ship speed is in the medium speed range, and selecting the high speed/rough weather sailing mode when the ship speed is in the high speed range,
The ship according to claim 4 , wherein the high speed/rough weather navigation mode is selected regardless of ship speed when wave height and wind speed exceed predetermined values. The marine vessel according to any one of claims 1 to 6, wherein the control unit increases the electric power supplied to the electric motor as the vessel speed increases in the same navigation mode. A main propeller, which is rotatably provided at the stern of the ship around an axis facing the ship's ship's ship's direction, and to which the power of the main engine is transmitted; and a main propeller, which is placed coaxially behind the main propeller in the ship's ship's direction and rotates in the opposite direction to the main propeller. A ship equipped with a counter-rotating propeller for ships equipped with an auxiliary propeller,
The auxiliary propeller is driven by an electric motor in a rudder valve of a movable rudder disposed rearward in the longitudinal direction of the main propeller, and has a auxiliary propeller boss having an external shape that constitutes a front end in the longitudinal direction of the rudder valve, and In a ship equipped with a sub-propeller blade that protrudes in the radial direction and has a diameter of 50% or more and 70% or less of the diameter of the propeller blade of the main propeller,
A ship comprising a control unit that drives the sub-propeller only when the speed of the ship is below a predetermined lower limit ship speed and the wave height and wind speed do not exceed predetermined values.

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