Ship and ship navigation method

Abstract

To provide a ship capable of reducing fuel consumption rate.SOLUTION: A ship comprises multiple main engines with the same rated rotation speed, a variable pitch propeller driven by the multiple main engines and with multiple blades capable of changing their pitch, and a reduction gear capable of transmitting each power of the multiple main engines to the variable pitch propeller. The reduction gear is configured that the reduction ratios of one main engine and the other main engine to the variable pitch propeller are different from each other when the variable pitch propeller is driven by at least two main engines among the multiple main engines. The variable pitch propeller is driven by the main engine with the larger reduction ratio to the variable pitch propeller among one main engine and the other main engine when the variable pitch propeller is driven by one main engine among the multiple main engines.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a ship and a method for navigation of a ship. [Background technology]

[0002] Patent Document 1 discloses a multi-engine single-screw ship propulsion system that includes a propeller for propelling a ship and multiple main engines (engines) that drive the propeller. In such a multi-engine single-screw ship propulsion system, the multiple main engines are connected to the propeller via a reduction gear. A clutch is provided between each main engine and the propeller, and is configured to be able to interrupt the transmission of driving force between each main engine and the propeller. This type of multi-engine single-screw ship propulsion system can switch between a navigation mode in which the propellers are driven by multiple main engines and a navigation mode in which the propellers are driven by only some of the multiple main engines by engaging and disengaging the clutch. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-154817 Summary of the Invention [Problem to be solved by the invention]

[0004] It is known that the fuel consumption rate and combustion state of a main engine for a ship such as that described in Patent Document 1 deteriorates as the load decreases. Also, a main engine for a ship is efficient when operated at a preset rated speed, and the efficiency decreases when operated at a speed lower than the rated speed. Furthermore, the pitch (blade angle) of the propeller blades is set so that the propulsion efficiency is high when the main engine is operated at the rated speed.

[0005] In the above-mentioned ship navigation schedule, two different sailing speeds may be set. For example, when multiple main engines are used and an attempt is made to change from a higher first sailing speed to a lower second sailing speed, the load of each main engine decreases, resulting in a deterioration in fuel consumption. In contrast, when the ship is navigated at the second sailing speed, if the propellers are driven only by some of the main engines, the decrease in the load of some of the main engines can be suppressed. However, when the blade pitch is constant, if the propellers are driven only by some of the main engines, a torque shortage occurs in some of the main engines. Therefore, it is necessary to use a variable pitch propeller that can change the blade pitch and reduce the blade pitch so that the main engine does not experience a torque shortage. However, when the blade pitch is reduced, the propeller efficiency decreases, resulting in a problem of a deterioration in the fuel consumption rate of the main engine.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a ship and a method for sailing a ship that can improve fuel consumption rate. [Means for solving the problem]

[0007] In order to solve the above problems, a ship according to the present disclosure includes a plurality of main engines, a controllable pitch propeller, and a reduction gear. The main engines have the same rated rotation speed. The controllable pitch propeller is rotationally driven by the main engines and includes a plurality of blades whose pitch is variable. The reduction gear is capable of transmitting the power of each of the main engines to the controllable pitch propeller. The reduction gear is configured such that, when the controllable pitch propeller is driven by at least two of the main engines, one of the main engines and the other of the main engines have different reduction ratios to the controllable pitch propeller. When the controllable pitch propeller is driven by one of the main engines, the reduction gear drives the controllable pitch propeller by the main engine having a larger reduction ratio to the controllable pitch propeller between the one of the main engines and the other of the main engines.

[0008] A method for sailing a ship according to the present disclosure is a method for sailing a ship as described above. The method for sailing a ship includes a course for sailing at a first sailing speed and a course for sailing at a second sailing speed lower than the first sailing speed. In the course for sailing at the first sailing speed, power of the first main engine and the second main engine is transmitted to the controllable pitch propeller, and the ship sails at the first sailing speed. In the course for sailing at the second sailing speed, power of only the second main engine is transmitted to the controllable pitch propeller, and the ship sails at the second sailing speed lower than the first sailing speed. Effect of the Invention

[0009] According to the ship and ship navigation method disclosed herein, the fuel consumption rate can be improved. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a side view of a marine vessel according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to the first embodiment of the present disclosure. [Diagram 3]FIG. 2 is a diagram showing a state in which power from a first main engine and a second main engine is transmitted to a controllable pitch propeller in a marine vessel according to an embodiment of the present disclosure. [Figure 4] FIG. 11 is a diagram showing a state in which only the power of the second main engine is transmitted to a controllable pitch propeller in a marine vessel according to an embodiment of the present disclosure. [Diagram 5] FIG. 1 is a diagram illustrating an example of marine characteristics of a ship according to an embodiment of the present disclosure. [Figure 6] FIG. 11 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to a second embodiment of the present disclosure. [Figure 7] FIG. 13 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to a third embodiment of the present disclosure. [Figure 8] FIG. 13 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to a modified example of the third embodiment of the present disclosure. [Figure 9] FIG. 11 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to another first modified example of the embodiment of the present disclosure. [Figure 10] FIG. 11 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to another second modified example of the embodiment of the present disclosure. [Figure 11] FIG. 13 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to another third modified example of the embodiment of the present disclosure. [Figure 12] FIG. 13 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to another fourth modified example of the embodiment of the present disclosure. [Figure 13] FIG. 13 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to another fifth modified example of the embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First Embodiment Hereinafter, a ship and a ship navigation method according to an embodiment of the present disclosure will be described with reference to FIGS. (Vessel configuration) 1, the ship 1 includes at least a hull 2, a controllable pitch propeller 20, and a propulsion unit 9. The type of the ship 1 is not limited to a specific one. Examples of the type of the ship 1 include a ferry, a RORO ship (Roll-on / Roll-off ship), and a PCTC (Pure Car & Truck Carrier).

[0012] (Hull configuration) As shown in Fig. 1, the hull 2 ​​has a pair of side panels 3A, 3B and a ship bottom 4 that form its outer hull. The side panels 3A, 3B are made up of a pair of side shell plates that form the port and starboard sides, respectively. The ship bottom 4 is made up of a ship bottom shell plate that connects the side panels 3A, 3B. The hull 2 ​​is provided with multiple decks 7, including an upper deck 8, inside.

[0013] (Controllable pitch propeller configuration) The controllable pitch propeller 20 is disposed outside the hull 2. The controllable pitch propeller 20 is provided at the rear end of a propeller drive shaft 22. The controllable pitch propeller 20 has a plurality of blades 21 arranged around the central axis of the propeller drive shaft 22. The controllable pitch propeller 20 is configured to be able to change the pitch (blade angle) of each of the plurality of blades 21. The controllable pitch propeller 20 rotates integrally with the propeller drive shaft 22 in a predetermined direction, and generates thrust to propel the hull 2.

[0014] (Composition of the Promotion Department) FIG. 2 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to this embodiment. An engine room 5 is formed within the hull 2. The engine room 5 is formed, for example, on the stern 2b side within the hull 2. The propulsion unit 9 drives a controllable pitch propeller 20 to propel the ship 1. The propulsion unit 9 is disposed in the engine room 5 within the hull 2. As shown in FIG. 2, the propulsion unit 9 includes at least a plurality of main engines 10 and a reduction gear 30.

[0015] The main engines 10 drive the controllable pitch propeller 20 via the reduction gears 30. The main engines 10 in this embodiment are all the same in rated speed. The main engines 10 are, for example, 500 to 800 rpm. In this embodiment, the main engines 10 include a first main engine 10A and a second main engine 10B. Each of the main engines 10 is set to have the highest efficiency (for example, fuel consumption rate) when operated at the rated speed. The main engines 10 are set so that the torque generated when operated at the rated speed can drive the controllable pitch propeller 20 at the pitch of the blades 21 that maximizes the propeller efficiency. The main engines 10 are, for example, internal combustion engines such as two-stroke diesel engines.

[0016] The first main engine 10A has a main engine output shaft 11A. The main engine output shaft 11A is rotationally driven about its central axis by the first main engine 10A. The second main engine 10B has a main engine output shaft 11B. The main engine output shaft 11B is rotationally driven about its central axis by the second main engine 10B.

[0017] (Reduction Gear Configuration) The reduction gear 30 is configured to be able to transmit the power of each of the multiple main engines 10 to the controllable pitch propeller 20. The reduction gear 30 includes a first reduction gear section 38A and a second reduction gear section 38B. The reduction gear 30 includes an output gear 31, a first input gear 32A, and a second input gear 32B to configure the first reduction gear section 38A and the second reduction gear section 38B. The output gear 31, the first input gear 32A, and the second input gear 32B are accommodated in a housing 35 of the reduction gear 30.

[0018] The output gear 31 is connected to the controllable pitch propeller 20 via the propeller drive shaft 22. As shown in FIG. 1, the propeller drive shaft 22 extends in the fore-aft direction FA. The rear end of the propeller drive shaft 22 protrudes from inside the hull 2 ​​toward the stern 2b in the fore-aft direction FA. As shown in FIG. 2, the front end of the propeller drive shaft 22 is connected to the output gear 31 inside the hull 2. The controllable pitch propeller 20 is fixed to the rear end of the propeller drive shaft 22. The output gear 31 and the controllable pitch propeller 20 rotate integrally with the propeller drive shaft 22.

[0019] The first input gear 32A is connected to the rear end of the main engine output shaft 11A. The first input gear 32A meshes with the output gear 31. The first input gear 32A has a smaller number of teeth than the output gear 31. The first reduction gear section 38A is capable of transmitting the power of the first main engine 10A to the controllable pitch propeller 20. The first reduction gear section 38A is composed of a first input gear 32A and an output gear 31. The first reduction gear section 38A reduces the rotation of the main engine output shaft 11A and transmits it to the propeller drive shaft 22. In this embodiment, the first input gear 32A and the output gear 31 constitute the first reduction gear section 38A, but one or more intermediate gears (not shown) may be provided between the first input gear 32A and the output gear 31.

[0020] The second input gear 32B is connected to the rear end of the main engine output shaft 11B. The second input gear 32B meshes with the output gear 31. The second input gear 32B has a smaller number of teeth than the output gear 31. The second reduction gear portion 38B is capable of transmitting the power of the second main engine 10B to the controllable pitch propeller 20. The second reduction gear portion 38B is composed of a second input gear 32B and an output gear 31. The second reduction gear portion 38B reduces the rotation of the main engine output shaft 11B and transmits it to the propeller drive shaft 22. In this embodiment, the second input gear 32B and the output gear 31 constitute the second reduction gear portion 38B, but one or more intermediate gears (not shown) may be provided between the second input gear 32B and the output gear 31.

[0021] Here, the number of teeth of the second input gear 32B is less than that of the first input gear 32A. Therefore, the reduction ratio of the variable pitch propeller 20 in the second reduction unit 38B (hereinafter referred to as the "reduction ratio of the second reduction unit 38B") is larger than the reduction ratio of the variable pitch propeller 20 in the first reduction unit 38A (hereinafter referred to as the "reduction ratio of the first reduction unit 38A"). The reduction ratio G2 of the second reduction unit 38B is preferably set such that, for example, G1 < G2 < (G1 + 1.00) with respect to the reduction ratio G1 of the first reduction unit 38A. Preferably, for example, G1 < G2 < (G1 + 0.50) with respect to the reduction ratio G1 of the first reduction unit 38A. In the following description, for example, the reduction ratio G1 of the first reduction unit 38A is set to 3.00, and the reduction ratio G2 of the second reduction unit 38B is set to 3.175. Note that the reduction ratio G1 of the first reduction unit 38A and the reduction ratio G2 of the second reduction unit 38B shown here are examples for helping the understanding of the following description, and do not limit the specific numerical values of the reduction ratio G1 of the first reduction unit 38A and the reduction ratio G2 of the second reduction unit 38B.

[0022] The speed reducer 30 includes a clutch 33. The clutch 33 can interrupt the power transmission between the first main engine 10A and the variable pitch propeller 20. The clutch 33 is provided, for example, between the first main engine 10A and the first input gear 32A. Note that the specific configuration of the clutch 33 is not limited at all, as long as it can interrupt the power transmission between the first main engine 10A and the variable pitch propeller 20.

[0023] FIG. 3 is a diagram showing a state in which the power of the first main engine and the second main engine is transmitted to the variable pitch propeller in a ship according to an embodiment of the present disclosure. FIG. 4 is a diagram showing a state in which only the power of the second main engine is transmitted to the variable pitch propeller in the ship according to the present embodiment. The reduction gear 30 is configured to be able to switch between a first navigation mode M1 in which the power of the first main engine 10A and the second main engine 10B is transmitted to the controllable pitch propeller 20 as shown in Fig. 3 and a second navigation mode M2 ​​in which the power of only the second main engine 10B is transmitted to the controllable pitch propeller 20 as shown in Fig. 4 by connecting and disconnecting the clutch 33. That is, as shown in Fig. 3, in the first navigation mode M1, when the first main engine 10A and the controllable pitch propeller 20 are connected by the clutch 33, the power of the first main engine 10A and the second main engine 10B is transmitted to the controllable pitch propeller 20. Also, as shown in Fig. 4, in the second navigation mode M2, when the connection between the first main engine 10A and the controllable pitch propeller 20 is cut off by the clutch 33, the power of only the second main engine 10B is transmitted to the controllable pitch propeller 20. In this manner, the vessel 1 is configured to be switchable between the first navigation mode M1 and the second navigation mode M2.

[0024] Fig. 5 is a diagram showing an example of vessel characteristics of a vessel according to an embodiment of the present disclosure. In Fig. 5, the vertical axis represents output (in other words, thrust by the propeller) and the horizontal axis represents the rotation speed of the main engine. Fig. 5 shows vessel characteristics L1 in a first navigation mode M1 and vessel characteristics L2 in a second navigation mode M2. In this embodiment, the ship 1 can select a first navigation speed V1 and a second navigation speed V2 during navigation. When the ship 1 navigates at the first navigation speed V1, the ship 1 transmits the power of the first main engine 10A and the second main engine 10B to the controllable pitch propeller 20 in the first navigation mode M1. As shown in FIG. 5, when the ship 1 navigates at the first navigation speed V1 in the first navigation mode M1, the second main engine 10B operates at the rated rotation speed Rs (for example, 600 rpm). This is because the reduction ratio of the second reduction unit 38B is larger than the reduction ratio of the first reduction unit 38A, and therefore the rotation speed of the second main engine 10B is lower than the rotation speed of the first main engine 10A. If the first main engine 10A is operated at the rated rotation speed Rs in the first navigation mode M1, the second main engine 10B will operate at a rotation speed exceeding the rated rotation speed. Therefore, in the first navigation mode M1 of this embodiment, the second main engine 10B is operated at the rated rotational speed Rs, and the first main engine 10A is operated at a rotational speed according to the ratio G1 / G2 between the reduction ratio G1 of the first reduction section 38A and the reduction ratio G2 of the second reduction section 38B.

[0025] Here, a specific example of the rotation speed according to the ratio G1 / G2 between the reduction ratio G1 of the first reduction section 38A and the reduction ratio G2 of the second reduction section 38B will be shown. For example, if the reduction ratio G1 of the first reduction section 38A is 3.00 and the reduction ratio G2 of the second reduction section 38B is 3.17, the ratio G1 / G2 between the reduction ratio G1 of the first reduction section 38A and the reduction ratio G2 of the second reduction section 38B is: (3.00 / 3.17)×100=approx. 94% It becomes. In the first navigation mode M1, the second main engine 10B is operated at a rated rotation speed (e.g., 600 rpm), and the first main engine 10A is operated at a rotation speed (600 rpm×0.94=approximately 567 rpm) that is approximately 94% of the rated rotation speed of the second main engine 10B. In this way, in the first navigation mode M1, when the second main engine 10B is operated at the rated rotation speed, and the first main engine 10A is operated at a rotation speed corresponding to the ratio G1 / G2 of the reduction ratio G1 of the first reduction unit 38A and the reduction ratio G2 of the second reduction unit 38B with respect to the rated rotation speed, the controllable pitch propeller 20 is driven at a rotation speed (600 rpm×1 / 3.17=189 rpm) corresponding to the rated rotation speed (e.g., 600 rpm) of the second main engine 10B and the reduction ratio G2 of the second reduction unit 38B.

[0026] In the above specific example, the rotation speed of the first main engine 10A is lower than the rotation speed of the second main engine 10B, so the output of the first main engine 10A in the first navigation mode M1 is lower than the output when the first main engine 10A is operated at the rated rotation speed. In other words, in the first navigation mode M1, the combined output of the first main engine 10A and the second main engine 10B, in other words, the output for driving the controllable pitch propeller 20, is lower than the output when both the first main engine 10A and the second main engine 10B are operated at the rated rotation speed. For example, in the first navigation mode M1, the combined output of the first main engine 10A and the second main engine 10B, i.e., the output for driving the propellers, is low compared to when both the first main engine 10A and the second main engine 10B are operated at the same rated speed and the pitch of the blades 21 of the controllable pitch propeller 20 is set to the ideal value of 30°. Therefore, in the first navigation mode M1, it is preferable to eliminate the possibility of a torque shortage by setting the pitch of the blades 21 of the controllable pitch propeller 20 to a value smaller than the ideal value of 30° (for example, 29°). This can increase the efficiency of the controllable pitch propeller 20.

[0027] In the second navigation mode M2, only the power of the second main engine 10B is transmitted to the controllable pitch propeller 20, and the ship navigates at a second navigation speed V2 that is lower than the first navigation speed V1. In the second navigation mode M2, the second main engine 10B is operated at the rated rotation speed Rs (100% output). When the controllable pitch propeller 20 is driven to navigate at the second navigation speed V2, the torque for driving the controllable pitch propeller 20, in other words, the torque of the propeller drive shaft 22, is greater when the controllable pitch propeller 20 is driven by the power of only the second main engine 10B than when the controllable pitch propeller 20 is driven by the power of only the first main engine 10A. Therefore, in the second navigation mode M2, it is possible to use a pitch (e.g., about 28°) that is larger than the maximum pitch value (e.g., about 25°) of the controllable pitch propeller 20 when driven by the power of only the first main engine 10A at the rated rotation speed Rs. In other words, in the second navigation mode M2, it is possible to adopt a marine characteristic L2 in which the pitch of the controllable pitch propeller 20 is larger by an amount that allows the torque to be larger than the marine characteristic L3 when only the first main engine 10A is used as shown in Fig. 5. This makes it possible to increase the propeller efficiency.

[0028] (Navigational Method of Ships) In the ship 1 of this embodiment, a first navigation speed V1 and a second navigation speed V2 can be selected during navigation. The navigation method for a ship according to this embodiment includes a route S11 (see FIG. 3) for navigation at the first navigation speed and a route S12 (see FIG. 4) for navigation at the second navigation speed.

[0029] The route S11 for traveling at the first navigation speed is performed when the first navigation speed is selected. As shown in FIG. 3, in the route S11 for traveling at the first navigation speed, the clutch 33 is used to shift to a first navigation mode M1 in which the power of the first main engine 10A and the second main engine 10B is transmitted to the controllable pitch propeller 20. In the route S11 for traveling at the first navigation speed, the second main engine 10B is operated at the rated rotation speed Rs, and the first main engine 10A is operated at a rotation speed corresponding to the ratio G1 / G2 of the reduction ratio G1 of the first reduction unit 38A and the reduction ratio G2 of the second reduction unit 38B with respect to the rated rotation speed Rs. As a result, the ship 1 travels at the first navigation speed V1.

[0030] The route S12 for traveling at the second navigation speed is performed when navigation at the second navigation speed V2 is selected. As shown in FIG. 4, for the route S12 for traveling at the second navigation speed, the clutch 33 is used to shift to a second navigation mode M2 ​​in which only the power of the second main engine 10B is transmitted to the controllable pitch propeller 20. For the route S12 for traveling at the second navigation speed, the second main engine 10B is operated at a rated speed Rs or faster. As a result, the ship 1 travels at a second navigation speed V2 that is lower than the first navigation speed V1.

[0031] (Action and effect) In the ship and the method of navigating the ship of the first embodiment, when the controllable pitch propeller 20 is driven by two main engines 10, the reduction gear 30 makes the first main engine 10A and the second main engine 10B have different reduction ratios for the controllable pitch propeller 20. When the controllable pitch propeller 20 is driven by one of the first main engine 10A and the second main engine 10B, the controllable pitch propeller 20 is driven by the second main engine 10B having a larger reduction ratio for the controllable pitch propeller 20. As a result, when the controllable pitch propeller 20 is driven by one main engine 10 to navigate at the second voyage speed V2, the torque for driving the controllable pitch propeller 20 can be increased compared to when the controllable pitch propeller 20 is driven by the first main engine 10A having a smaller reduction ratio for the controllable pitch propeller 20. This makes it possible to increase the pitch of the controllable pitch propeller 20 when driving the controllable pitch propeller 20 with one main engine 10. As a result, when driving the controllable pitch propeller 20 with one main engine 10, a marine characteristic L2 with a larger pitch can be adopted, thereby increasing the propeller efficiency and improving the propulsion efficiency of the ship 1 by the controllable pitch propeller 20. Therefore, it becomes possible to improve the fuel consumption rate of the ship 1.

[0032] In the first embodiment, in the first navigation mode M1, the first main engine 10A and the controllable pitch propeller 20 can be connected by the clutch 33, so that the controllable pitch propeller 20 can be easily driven by both the first main engine 10A and the second main engine 10B. In addition, the clutch 33 can interrupt the transmission of power between the first main engine 10A and the controllable pitch propeller 20, so that in the second navigation mode M2, the controllable pitch propeller 20 can be easily driven only by the second main engine 10B. Furthermore, in the second navigation mode M2, the controllable pitch propeller 20 can be driven only by the second main engine 10B, which is the main engine 10 having a larger reduction ratio with respect to the controllable pitch propeller 20. Therefore, the fuel consumption rate of the ship 1 can be improved without complicating the structure.

[0033] Furthermore, in the above first embodiment, in the first navigation mode M1, the power of both the first main engine 10A and the second main engine 10B is transmitted to the controllable pitch propeller 20, so that the ship can efficiently navigate at a higher first navigation speed V1. In the second navigation mode M2, since only the power of the second main engine 10B is transmitted to the controllable pitch propeller 20, the output of the second main engine 10B in the second navigation mode M2 ​​can be made higher than the output of each main engine when multiple main engines having the same rotation speed are used to navigate at the second navigation speed V2. Therefore, the main engine 10 can be operated with a good fuel consumption rate.

[0034] In addition, in the navigation method for the ship of the first embodiment, during the course S12 in which the ship navigates at the second navigation speed, the controllable pitch propeller 20 is driven only by the second main engine 10B. In this case, the torque of the controllable pitch propeller 20 can be increased compared to when the controllable pitch propeller 20 is driven only by the first main engine 10A. Therefore, the pitch of the controllable pitch propeller 20 can be increased to increase the propeller efficiency, and the second main engine 10B can be operated in a favorable fuel consumption rate and combustion state.

[0035] Second Embodiment Next, a second embodiment of the ship and ship navigation method according to the present disclosure will be described. The second embodiment described below differs from the first embodiment only in that it includes a sliding mechanism 34. Therefore, the same parts as those in the first embodiment are denoted by the same reference numerals and will not be described again. FIG. 6 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to a second embodiment of the present disclosure. As shown in FIG. 6, in a propulsion section 9B of a boat 1 of this embodiment, a reduction gear 30B includes a first reduction gear section 38A, a second reduction gear section 38B, a clutch 33, and a slip mechanism 34. The slip mechanism 34 makes it possible to increase the rotation speed of the first main engine 10A by slipping the transmission of power between the first main engine 10A and the controllable pitch propeller 20. An example of such a slip mechanism 34 is a slipping clutch. When the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B in the first navigation mode M1, the slip mechanism 34 causes the transmission of power between the first main engine 10A and the controllable pitch propeller 20 to slip, thereby increasing the rotation speed of the first main engine 10A.

[0036] (Action and effect) In the boat 1 of the above embodiment, as in the first embodiment, the fuel consumption rate of the boat 1 can be improved. Furthermore, in the first navigation mode M1, when the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B, the first main engine 10A has a smaller reduction ratio of the first reduction unit 38A in the reduction gear 30 to the controllable pitch propeller 20 than the second main engine 10B. Therefore, the rotation speed of the first main engine 10A is lower than that of the second main engine 10B. In contrast, in the ship 1 of the second embodiment described above, by providing the slip mechanism 34, when the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B in the first navigation mode M1, the rotation speed of the first main engine 10A can be increased by slipping the transmission of power between the first main engine 10A and the controllable pitch propeller 20. As a result, even when the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B, the rotation speed of the first main engine 10A can be increased, making it possible to operate in a more efficient state.

[0037] <Third embodiment> Next, a third embodiment of the ship and ship navigation method according to the present disclosure will be described. The third embodiment described below differs from the first embodiment only in that a first driven machine 41 is provided, so the same parts as those in the first embodiment are denoted by the same reference numerals and will not be described again. FIG. 7 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to a third embodiment of the present disclosure. As shown in FIG. 7, a propulsion section 9C of a ship 1 in this embodiment includes a plurality of main engines 10, a reduction gear 30, and a first driven machine 41. The first driven machine 41 is driven by the first main engine 10A. The first driven machine 41 is provided, for example, on the main engine output shaft 11A. An example of the first driven machine 41 is a shaft generator or the like. In the first navigation mode M1, when the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B, the first driven machine 41 is driven by the main engine output shaft 11A being rotated by the first main engine 10A. The first driven machine 41 consumes a part of the output of the first main engine 10A.

[0038] (Action and effect) In the boat 1 of the above embodiment, as in the first embodiment, the fuel consumption rate of the boat 1 can be reduced. Furthermore, in the first navigation mode M1, when the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B, the first main engine 10A has a smaller reduction ratio of the first reduction unit 38A in the reduction gear 30 to the controllable pitch propeller 20 than the second main engine 10B. Therefore, the rotation speed of the first main engine 10A becomes lower than that of the second main engine 10B, and the efficiency of the first main engine 10A decreases. In contrast, in the ship 1 of the above embodiment, by providing the first driven machine 41, when the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B in the first navigation mode M1, the first driven machine 41 can be driven by the first main engine 10A, and a part of the output of the first main engine 10A can be consumed. As a result, even when the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B, the first main engine 10A can be increased and the ship can be operated in a more efficient state.

[0039] (Modification of the third embodiment) FIG. 8 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to a modified example of the third embodiment of the present disclosure. In the above third embodiment, the ship 1 is provided with a first driven unit 41 driven by a first main engine 10A. In addition, as shown in FIG. 8, the propulsion section 9D of the ship 1 may be provided with a plurality of main engines 10, a reduction gear 30, a first driven unit 41, and a second driven unit 42. The second driven machine 42 is driven by the second main engine 10B. The second driven machine 42 is provided, for example, on the main engine output shaft 11B. An example of the second driven machine 42 is a shaft generator.

[0040] In the configuration shown in the third embodiment, in the second navigation mode M2, when the controllable pitch propeller 20 is driven only by the second main engine 10B, it is not possible to drive the first driven machine 41. In contrast, by providing the second driven machine 42 as in this modified example, when the controllable pitch propeller 20 is driven only by the second main engine 10B, it is possible to drive a shaft generator as the second driven machine 42 and utilize the second driven machine 42.

[0041] (Other embodiments) Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of the present disclosure are also included. In each of the above embodiments and the modified examples thereof, a so-called two-engine, one-shaft configuration including the first main engine 10A, the second main engine 10B, and one controllable pitch propeller 20 has been exemplified, but the present invention is not limited to this.

[0042] FIG. 9 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to another first modified example of the embodiment of the present disclosure. For example, as shown in Fig. 9, the ship 1 may include a first main engine 10A, a second main engine 10B, and a third main engine 10C as the multiple main engines 10, and one controllable pitch propeller 20. In this modification, each of the first main engine 10A, the second main engine 10B, and the third main engine 10C transmits power to the controllable pitch propeller 20 via one reduction gear 30D. The reduction gear 30D is connected to the main engine output shaft 11A of the first main engine 10A, the main engine output shaft 11B of the second main engine 10B, and the main engine output shaft 11C of the third main engine 10C. The reduction gear 30D is configured such that, in at least two of the multiple main engines 10 (the first main engine 10A, the second main engine 10B, and the third main engine 10C), the reduction ratio to the controllable pitch propeller 20 is different between one main engine 10 and the other main engine 10.

[0043] FIG. 10 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to another second modified example of the embodiment of the present disclosure. 10, the ship 1 includes a first main engine 10A, a second main engine 10B, and a third main engine 10C as a plurality of main engines 10, and one controllable pitch propeller 20. In this modification, each of the first main engine 10A, the second main engine 10B, and the third main engine 10C transmits power to the controllable pitch propeller 20 via two reducers 30E, 30F.

[0044] The reduction gear 30E is connected to a main engine output shaft 11A of the first main engine 10A and a main engine output shaft 11B of the second main engine 10B among the multiple main engines 10. The reduction gear 30F is connected to a reduction gear output shaft 101 of the reduction gear 30E and a main engine output shaft 11C of the third main engine 10C. In this configuration, at least one of the reducers 30E and 30F is configured to have a reduction ratio with respect to the controllable pitch propeller 20 that is different from each other.

[0045] FIG. 11 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to another third modified example of the embodiment of the present disclosure. 1, the ship 1 may include a first main engine 10A, a second main engine 10B, and a third main engine 10C, and two controllable pitch propellers 20A and 20B as the multiple main engines 10. In this modification, each of the first main engine 10A, the second main engine 10B, and the third main engine 10C transmits power to the controllable pitch propeller 20 via three reducers 30G, 30H, and 30I.

[0046] A main engine output shaft 11B of the second main engine 10B is connected to the reduction gear 30G. The reduction gear 30G has two reduction gear output shafts 102 and 103. The reducer 30H is connected to a main engine output shaft 11A of the first main engine 10A and a reducer output shaft 102. The reducer 30H is connected to a propeller drive shaft 22A of one of the controllable pitch propellers 20A.

[0047] The reducer 30I is connected to a main engine output shaft 11C of the third main engine 10C and a reducer output shaft 103. The reducer 30I is connected to a propeller drive shaft 22B of the other controllable pitch propeller 20B. In this configuration, at least one of the reducers 30G, 30H, and 30I is configured to have a reduction ratio with respect to the controllable pitch propellers 20A, 20B that is different from one another.

[0048] FIG. 12 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to another fourth modified example of the embodiment of the present disclosure. 12, the ship 1 may include a first main engine 10A, a second main engine 10B, and a third main engine 10C, and two controllable pitch propellers 20C, 20D as the multiple main engines 10. In this modification, the first main engine 10A, the second main engine 10B, and the third main engine 10C transmit power to the controllable pitch propellers 20D, 20E via two reduction gears 30J, 30K, respectively.

[0049] The main engine output shaft 11A of the first main engine 10A and the main engine output shaft 11B of the second main engine 10B are connected to the reduction gear 30J. The reduction gear 30J is connected to the propeller drive shaft 22C of one of the controllable pitch propellers 20C. A main engine output shaft 11C of the third main engine 10C is connected to the reduction gear 30K. The reduction gear 30K is connected to a propeller drive shaft 22D of the other controllable pitch propeller 20D. In this configuration, the reduction gears 30D are configured to have different reduction ratios with respect to the controllable pitch propeller 20C.

[0050] FIG. 13 is a diagram showing a schematic configuration of a plurality of main engines, a reduction gear, and a controllable pitch propeller according to another fifth modified example of the embodiment of the present disclosure. 13, the ship 1 may include a first main engine 10A, a second main engine 10B, a third main engine 10C, and a fourth main engine 10D, and two controllable pitch propellers 20F, 20G as the multiple main engines 10. In this modification, the first main engine 10A and the second main engine 10B transmit power to the controllable pitch propellers 20F, 20G via reduction gears 30L, 30M, respectively.

[0051] As in the first embodiment, the main engine output shaft 11A of the first main engine 10A and the main engine output shaft 11B of the second main engine 10B are connected to the reduction gear 30L. The reduction gear 30L is connected to the propeller drive shaft 22F of one of the controllable pitch propellers 20F. As in the first embodiment, the main engine output shaft 11C of the third main engine 10C and the main engine output shaft 11D of the fourth main engine 10D are connected to the reduction gear 30M. The reduction gear 30M is connected to the propeller drive shaft 22G of the other controllable pitch propeller 20G. In this configuration, the reduction gears 30L, 30M are configured to have different reduction ratios to the controllable pitch propellers 20F, 20G.

[0052] <Additional Notes> The ship 1 and the navigation method of the ship 1 described in each embodiment can be understood, for example, as follows.

[0053] (1) The ship 1 in the first embodiment comprises a plurality of main engines 10 having the same rated rotational speed, a controllable pitch propeller 20 that is rotationally driven by the plurality of main engines 10 and has a plurality of blades 21 whose pitch can be changed, and a reduction gear 30 capable of transmitting the power of each of the plurality of main engines 10 to the controllable pitch propeller 20, wherein the reduction gear 30 is configured such that, when the controllable pitch propeller 20 is driven by at least two of the plurality of main engines 10, the reduction gear 30 has different reduction ratios to the controllable pitch propeller 20 between one of the plurality of main engines 10 and the other of the main engines 10, and when the controllable pitch propeller 20 is driven by one of the plurality of main engines 10, the controllable pitch propeller 20 is driven by the main engine 10 having a larger reduction ratio to the controllable pitch propeller 20 between the one of the plurality of main engines 10 and the other of the main engines 10.

[0054] As a result, when driving the controllable pitch propeller 20 with one main engine 10 to navigate at a specified sailing speed, the torque can be increased compared to when the controllable pitch propeller 20 is driven by a main engine 10 having a smaller reduction ratio to the controllable pitch propeller 20. By increasing the torque generated by the main engine 10, the pitch of the blades 21 of the controllable pitch propeller 20 can be increased. This increases the propeller efficiency, and also increases the propulsion efficiency by the controllable pitch propeller 20. As a result, the fuel consumption rate of the ship 1 can be improved.

[0055] (2) The ship 1 according to a second aspect is the ship 1 of (1), wherein the multiple main engines 10 include a first main engine 10A and a second main engine 10B, and the reduction gear 30 includes a first reduction section 38A having a first reduction ratio and capable of transmitting the power of the first main engine 10A to the controllable pitch propeller 20, a second reduction section 38B having a second reduction ratio greater than the first reduction ratio and capable of transmitting the power of the second main engine 10B to the controllable pitch propeller 20, and a clutch 33 that interrupts the transmission of power between the first main engine 10A and the controllable pitch propeller 20.

[0056] As a result, when the controllable pitch propeller 20 is driven by two main engines 10, the first main engine 10A and the second main engine 10B, the first main engine 10A and the second main engine 10B can be configured to have different reduction gear ratios for the controllable pitch propeller 20. When the controllable pitch propeller 20 is driven by the second main engine 10B as one of the main engines 10, the first main engine 10A, which is the main engine 10 having a smaller reduction gear ratio for the controllable pitch propeller 20, of the first main engine 10A and the second main engine 10B, can be disconnected by the clutch 33, and the controllable pitch propeller 20 can be driven only by the second main engine 10B, which is the main engine 10 having a larger reduction gear ratio for the controllable pitch propeller 20. Therefore, the fuel consumption rate of the ship 1 can be improved without complicating the structure.

[0057] (3) The ship 1 of the third aspect is the ship 1 of (2) and is configured to be switchable between a first navigation mode M1 in which the power of the first main engine 10A and the second main engine 10B is transmitted to the controllable pitch propeller 20 and the ship travels at a first navigation speed V1, and a second navigation mode M2 ​​in which the power of only the second main engine 10B is transmitted to the controllable pitch propeller 20 and the ship travels at a second navigation speed V2 lower than the first navigation speed V1.

[0058] As a result, in the first navigation mode M1, the power of the first main engine 10A and the second main engine 10B is transmitted to the controllable pitch propeller 20, thereby enabling the ship to navigate at a first navigation speed that is a high navigation speed. In the second navigation mode M2, the power of only the second main engine 10B is transmitted to the controllable pitch propeller 20, thereby enabling the ship to navigate at a second navigation speed V2 that is lower than the first navigation speed V1. Since the output of the second main engine 10B can be increased when navigating at the second navigation speed V2, which has a relatively lower output than that at the first navigation speed V1, the ship can be operated in a state with a good fuel consumption rate.

[0059] (4) The ship 1 according to a fourth aspect is the ship 1 of (2) or (3), further comprising a slip mechanism 34 that enables the rotation speed of the first main engine 10A to be increased by slipping the transmission of power between the first main engine 10A and the controllable pitch propeller 20.

[0060] When the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B, the first main engine 10A has a smaller reduction ratio of the first reduction unit 38A in the reduction gear 30 to the controllable pitch propeller 20 than the second main engine 10B. Therefore, the rotation speed of the first main engine 10A is lower than that of the second main engine 10B, and the efficiency of the first main engine 10A is reduced. In response to this, the slip mechanism 34 is provided to slip the transmission of power between the first main engine 10A and the controllable pitch propeller 20, thereby making it possible to increase the rotation speed of the first main engine 10A. As a result, even when the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B, it is possible to increase the rotation speed of the first main engine 10A and operate in an efficient state.

[0061] (5) The ship 1 according to a fifth aspect is any one of the ships 1 according to (2) to (4), and further includes a first driven machine 41 driven by the first main engine 10A. The first driven machine 41 may be a shaft generator.

[0062] When the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B, the first main engine 10A has a smaller reduction ratio of the first reduction unit 38A in the reduction gear 30 to the controllable pitch propeller 20 than the second main engine 10B. Therefore, the rotation speed of the first main engine 10A is lower than that of the second main engine 10B, and the efficiency of the first main engine 10A is reduced. In response to this, the first main engine 10A can drive the first driven machine 41 and consume a part of the output of the first main engine 10A. This makes it possible to operate the first main engine 10A in a more efficient state, even when the controllable pitch propeller 20 is driven by the first main engine 10A and the second main engine 10B.

[0063] (6) The ship 1 according to a sixth aspect is any one of the ships 1 in (5), further including a second driven machine 42 driven by the second main engine 10B. The second driven machine 42 may be a shaft generator.

[0064] When the first driven machine 41 driven by the first main engine 10A is provided, the first driven machine 41 cannot be driven when the controllable pitch propeller 20 is driven only by the second main engine 10B. In contrast, when the second driven machine 42 is provided, the second driven machine 42 can be driven when the controllable pitch propeller 20 is driven only by the second main engine 10B.

[0065] (7) A navigation method for a ship 1 according to a seventh aspect is any one of the navigation methods for a ship 1 according to (2) to (6), and includes a route S11 in which the power of the first main engine 10A and the second main engine 10B are transmitted to the controllable pitch propeller 20 and the ship travels at a first navigation speed, and a route S12 in which the power of only the second main engine 10B is transmitted to the controllable pitch propeller 20 and the ship travels at a second navigation speed lower than the first navigation speed.

[0066] As a result, when the controllable pitch propeller 20 is driven only by the second main engine 10B on the course S12 navigating at the second sailing speed, the torque for driving the controllable pitch propeller 20 can be made larger than when the controllable pitch propeller 20 is driven only by the first main engine 10A. Therefore, the pitch of the blades 21 of the controllable pitch propeller 20 can be made closer to the pitch when operating at the rated rotation speed. This improves the propeller efficiency and the propulsion efficiency by the propeller. In addition, since the marine characteristic L2 when the pitch is larger can be applied, the output of the second main engine 10B can be increased at the same rotation speed, and the fuel consumption rate and combustion state of the second main engine 10B can be improved. [Explanation of symbols]

[0067] REFERENCE SIGNS LIST 1...ship 2...hull 2b...stern 3A, 3B...shipside 4...ship bottom 5...engine room 7...deck 8...upper deck 9, 9B, 9C, 9D...propulsion section 10...main engine 10A...first main engine 10B...second main engine 10C...third main engine 10D...fourth main engine 11A-11D...main engine output shaft 20A-20G...controllable pitch propeller 21...blade 22, 22A-22G...propeller drive shaft 30, 30B-30M...reduction gear 31...output gear 32A...first input gear 32B...second input gear 33...clutch 34...slip mechanism 35...housing 38A...first reduction gear section 38B...second reduction gear section 41...first driven engine 42...second driven engine 101~103...Reduction gear output shaft FA...Fore-stern direction

Claims

1. A plurality of main engines having the same rated speed; A variable pitch propeller that is rotationally driven by the main engines and has a plurality of blades whose pitch can be changed; a reduction gear capable of transmitting power of each of the plurality of main engines to the controllable pitch propeller, The reducer includes: When the controllable pitch propeller is driven by at least two of the main engines, the reduction gear ratios of one of the main engines and the other of the main engines are different from each other, When the controllable pitch propeller is driven by one of the main engines, the controllable pitch propeller is driven by the main engine having a larger reduction ratio to the controllable pitch propeller between the one main engine and the other main engine. ship.

2. The plurality of main engines include A first main engine; a second main engine; The reducer includes: a first reduction gear unit capable of transmitting power of the first main engine to the controllable pitch propeller and having a first reduction gear ratio; a second reduction gear unit capable of transmitting power of the second main engine to the controllable pitch propeller and having a second reduction gear ratio greater than the first reduction gear ratio; a clutch that interrupts the transmission of power between the first main engine and the controllable pitch propeller.

2. The watercraft of claim 1.

3. a first navigation mode in which power of the first main engine and the second main engine is transmitted to the controllable pitch propeller and the ship travels at a first navigation speed; a second navigation mode in which power of only the second main engine is transmitted to the controllable pitch propeller and the vessel navigates at a second navigation speed lower than the first navigation speed.

3. The watercraft of claim 2.

4. The present invention further includes a slip mechanism that enables the rotation speed of the first main engine to be increased by slipping the transmission of power between the first main engine and the controllable pitch propeller.

3. The watercraft of claim 2.

5. a first driven machine driven by the first main engine.

3. The watercraft of claim 2.

6. a second driven machine driven by the second main engine.

6. A watercraft as claimed in claim 5.

7. 3. A method for navigation of a ship according to claim 2, comprising: a course in which power of the first main engine and the second main engine is transmitted to the controllable pitch propeller and the ship travels at a first service speed; a course in which power of only the second main engine is transmitted to the controllable pitch propeller and the vessel travels at a second service speed lower than the first service speed, How a ship navigates.

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