Double-speed-ratio marine gearbox

Abstract

The invention belongs to the technical field of ships, and discloses a double-speed-ratio marine gearbox. The double-speed-ratio marine gearbox comprises a box body, an input shaft system, an output shaft system, a PTO shaft system and a PTH shaft system, wherein the input shaft system, the output shaft system, the PTO shaft system and the PTH shaft system are all arranged in the box body; both the input shaft system and the PTO shaft system can be connected to the diesel engine, the input shaft system is in transmission connection with the output shaft system and the PTH shaft system, the PTO shaft system is in transmission connection with the PTH shaft system, and both the PTH shaft system and the PTO shaft system can be connected to the shaft generator; the input shaft system is provided with an input clutch, the PTO shaft system is provided with a PTO clutch, and the PTH shaft system is provided with a PTH clutch. Switching of two speed ratios is achieved through engagement and disengagement of the clutches, so that the speed ratios of different gears can be replaced without shutdown, and the size is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of ships, and in particular to a dual-speed ratio marine gearbox. Background Art

[0002] At present, marine fishing vessels such as tugboats and trawlers often have two operating conditions during operation, one of which is no-load sailing and the other is towing sailing. In order to make the diesel engine work at rated conditions in both operating conditions, the gearbox needs to have two speed ratios to meet the needs of the ship to obtain the best propulsion efficiency in both operating conditions. A shaft generator will also be configured to improve the utilization rate of the diesel engine power and serve as a backup power output when the diesel engine fails. Therefore, it also needs to have PTO mode (Power Take-Off, that is, the diesel engine is used as the power source and the shaft generator is used as the generator) and PTH mode (Power Take-Home, that is, the diesel engine fails and the shaft generator is used as the power source).

[0003] The traditional two-speed ratio gearbox consists of two sets of gears with different speed ratios. The gear sets with different speed ratios are replaced by shifting the fork, so as to realize the switching operation of two speed ratios. However, the fork shifting needs to be stopped in the middle to replace, which also poses the risk of the ship losing power and affects the continuous operation of the shaft generator. In addition, the setting of two gear sets with different speed ratios, as well as the setting of the PTO shaft system and the PTH shaft system, increases the volume occupancy rate.

[0004] Therefore, there is an urgent need for a dual-speed ratio marine gearbox to solve the above technical problems. Summary of the invention

[0005] One object of the present invention is to provide a dual-speed ratio marine gearbox, which can achieve switching between two speed ratios by engaging and disengaging each clutch, thereby achieving the speed ratio of different gears without stopping the machine and reducing the size.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A dual-speed ratio marine gearbox comprises a housing, an input shaft system, an output shaft system, a PTO shaft system and a PTH shaft system, wherein the input shaft system, the output shaft system, the PTO shaft system and the PTH shaft system are all arranged in the housing;

[0008] The input shaft system and the PTO shaft system can both be connected to the diesel engine, the input shaft system is respectively connected to the output shaft system and the PTH shaft system, the PTO shaft system is connected to the PTH shaft system, and the PTH shaft system and the PTO shaft system can both be connected to a shaft generator;

[0009] The input shaft system is provided with an input clutch, the PTO shaft system is provided with a PTO clutch, and the PTH shaft system is provided with a PTH clutch.

[0010] Optionally, the input shaft system includes an input oil cylinder, the output end of the input oil cylinder is connected to the outer ring of the input clutch, and the input end of the input oil cylinder can be connected to the diesel engine.

[0011] Optionally, the input shaft system further includes a main transmission gear shaft, which is connected to the inner ring of the input clutch, and the output shaft system includes an output gear, which is meshedly connected to the main transmission gear shaft to achieve a transmission connection between the input shaft system and the output shaft system.

[0012] Optionally, the input shaft system further includes a PTH gear, which is arranged on the main drive gear shaft, and the PTH shaft system includes a PTH hollow gear shaft, which is connected to the outer ring of the PTH clutch, and the PTH hollow gear shaft is meshedly connected with the PTH gear to realize the transmission connection between the input shaft system and the PTH shaft system.

[0013] Optionally, the input shaft system also includes a PTO gear, which is arranged on the input cylinder, and the PTO shaft system includes a PTO hollow gear shaft, which is connected to the outer ring of the PTO clutch, and the PTO hollow gear shaft and the PTO gear are meshingly connected to realize the transmission connection between the input shaft system and the PTO shaft system.

[0014] Optionally, the PTH shaft system further comprises a first transmission shaft, the first transmission shaft is connected to the inner ring of the PTH clutch, and the first transmission shaft can be connected to the shaft generator;

[0015] The PTO shaft system further includes a second transmission shaft, which is connected to the inner ring of the PTO clutch and is transmission-connected to the first transmission shaft.

[0016] Optionally, the PTO shaft system and the PTH shaft system are coaxially arranged so that the two are transmission-connected.

[0017] Optionally, it also includes an oil circuit system, which is arranged in the above-mentioned box body, and the above-mentioned oil circuit system includes a lubricating oil supply circuit and a hydraulic oil supply circuit. The above-mentioned lubricating oil supply circuit is used to supply lubricating oil to the above-mentioned input shaft system, the above-mentioned output shaft system, the above-mentioned PTO shaft system and the above-mentioned PTH shaft system, and the above-mentioned hydraulic oil supply circuit is used to supply hydraulic oil to the above-mentioned input shaft system, the above-mentioned output shaft system, the above-mentioned PTO shaft system and the above-mentioned PTH shaft system.

[0018] Optionally, the hydraulic oil supply circuit includes a first circuit and a second circuit, both of which are connected to a hydraulic oil gear pump, the first circuit can selectively supply hydraulic oil to the input clutch or the PTH clutch, and the second circuit is used to supply hydraulic oil to the PTO clutch.

[0019] Optionally, the first circuit is provided with a first reversing valve having two channels, one of the two channels being connected to the input clutch, and the other being connected to the PTH clutch, and the first reversing valve can switch the connection state between the two channels and the hydraulic oil gear pump.

[0020] Beneficial effects of the present invention:

[0021] The present invention provides a dual-speed ratio marine gearbox, which can switch power input of two different transmission ratios of diesel engine-input shaft system-output shaft system and diesel engine-PTO shaft system-PTH shaft system-input shaft system-output shaft system by controlling the engagement and disengagement of input clutch, PTO clutch and PTH clutch during use, thereby realizing the switching of two different speed ratios, and the switching process does not require shutdown, the replacement speed is fast, and the continuous supply of ship power and the continuous operation of shaft belt generator are not affected. At the same time, the number of parts is greatly reduced, the compactness of the structure is improved, and the size of the dual-speed ratio marine gearbox is reduced. In addition, the dual-speed ratio gearbox can also realize the operation of two modes: driving the shaft belt generator while the diesel engine inputs power, and using the shaft belt generator to output power when the diesel engine fails. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a cross-sectional view of a dual-speed ratio marine gearbox provided by a specific embodiment of the present invention;

[0023] Figure 2 It is an axonometric view of a dual-speed ratio marine gearbox provided by a specific embodiment of the present invention from one perspective;

[0024] Figure 3 is an axonometric view of another perspective of a dual-speed ratio marine gearbox provided by a specific embodiment of the present invention;

[0025] Figure 4 It is a working principle diagram of the oil circuit system provided by the specific implementation mode of the present invention.

[0026] In the figure:

[0027] 10. Box body;

[0028] 20. Input shaft system; 21. Input clutch; 22. Input cylinder; 23. Main drive gear shaft; 24. PTH gear; 25. PTO gear;

[0029] 30. Output shaft system; 31. Output gear; 32. Output shaft; 33. Thrust bearing;

[0030] 40. PTO shaft system; 41. PTO clutch; 42. PTO hollow gear shaft;

[0031] 50. PTH shaft system; 51. PTH clutch; 52. PTH hollow gear shaft;

[0032] 60. Connecting shaft;

[0033] 71. Hydraulic oil supply circuit; 7101. First circuit; 7102. Second circuit; 711. Hydraulic oil gear pump; 712. Reversing solenoid valve; 713. Hydraulic oil filter; 714. Pilot relief valve; 715. Hydraulic oil electric standby pump; 72. Lubricating oil supply circuit; 721. Lubricating oil gear pump; 722. Lubricating oil filter; 723. Lubricating oil cooler; 724. Lubricating oil electric standby pump; 73. Instrument panel; 74. Machine-side control box. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0035] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0037] In the description of this embodiment, the terms "upper", "lower", "left", "right", etc., and the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplified operation, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0038] Refer to the following Figures 1 to 4 The invention discloses a dual-speed ratio marine gearbox.

[0039] Please refer to Figure 1 Specifically, the dual-speed ratio marine gearbox includes a housing 10, an input shaft system 20, an output shaft system 30, a PTO shaft system 40 and a PTH shaft system 50. The input shaft system 20, the output shaft system 30, the PTO shaft system 40 and the PTH shaft system 50 are all arranged in the housing 10; the input shaft system 20 and the PTO shaft system 40 can both be connected to the diesel engine, the input shaft system 20 is respectively connected to the output shaft system 30 and the PTH shaft system 50, the PTO shaft system 40 is connected to the PTH shaft system 50, and the PTH shaft system 50 and the PTO shaft system 40 can both be connected to the shaft generator; the input shaft system 20 is provided with an input clutch 21, the PTO shaft system 40 is provided with a PTO clutch 41, and the PTH shaft system 50 is provided with a PTH clutch 51.

[0040] The dual-speed ratio marine gearbox in this embodiment can switch the power input of two different transmission ratios of diesel engine-input shaft system 20-output shaft system 30 and diesel engine-PTO shaft system 40-PTH shaft system 50-input shaft system 20-output shaft system 30 by controlling the engagement and disengagement of the input clutch 21, the PTO clutch 41 and the PTH clutch 51, thereby realizing the switching of two different speed ratios, and the switching process does not require shutdown, the replacement speed is fast, and it will not affect the continuous supply of ship power and the continuous operation of the shaft belt generator. At the same time, the number of parts is greatly reduced, the compactness of the structure is improved, and the size of the dual-speed ratio marine gearbox is reduced. In addition, the dual-speed ratio gearbox can also realize the operation of two modes: driving the shaft belt generator while the diesel engine inputs power, and using the shaft belt generator to output power when the diesel engine fails.

[0041] Specifically, the dual-speed ratio marine gearbox includes four propulsion modes, including full-speed propulsion mode, hybrid power output mode, low-speed cruising mode and PTH mode. When the full-speed propulsion mode is in operation: when the input clutch 21 is engaged, the PTO clutch 41 and the PTH clutch 51 are disengaged, the power output by the diesel engine is output to the input shaft system 20 through the input clutch 21 and is transmitted to the output shaft system 30, so as to achieve full-speed propulsion of the ship. At this time, the PTO shaft system 40 and the PTH shaft system 50 are not in operation. When the hybrid power output mode is in operation: when the input clutch 21 and the PTO clutch 41 are engaged, and the PTH clutch 51 is disengaged, the power output by the diesel engine is output to the input shaft system 20 through the input clutch 21 and is transmitted to the output shaft system 30 and the PTO clutch 41 respectively, so as to achieve the propulsion of the first speed ratio of the ship and drive the shaft belt generator to generate electricity. At this time, the PTH shaft system 50 is not in operation. When the low-speed cruise mode is in operation: when the input clutch 21 is disengaged and the PTO clutch 41 and the PTH clutch 51 are engaged, the power output by the diesel engine is output to the PTO clutch 41 and transmitted to the PTO shaft system 40, and then transmitted to the PTH shaft system 50 through the PTH clutch 51, and then transmitted to the PTH shaft system 50 through the PTH shaft system 50, and then transmitted to the input shaft system 20 and the output shaft system 30 in sequence through the PTH shaft system 50, while achieving the propulsion of the ship's second speed ratio, it also drives the shaft generator to generate electricity. When the PTH mode is in operation: when the diesel engine fails, the input clutch 21 and the PTO clutch 41 are disengaged and the PTH clutch 51 is engaged, the power output by the shaft generator is output to the PTH shaft system 50 through the PTH clutch 51, and then transmitted to the input shaft system 20 and the output shaft system 30 in sequence through the PTH shaft system 50, achieving the propulsion of the ship at a lower speed.

[0042] In this embodiment, the input shaft system 20 includes an input cylinder 22, the output end of the input cylinder 22 is connected to the outer ring of the input clutch 21, and the input end of the input cylinder 22 can be connected to the diesel engine, thereby realizing the connection between the input shaft system 20 and the diesel engine.

[0043] Further, the input shaft system 20 further includes a main transmission gear shaft 23, which is connected to the inner ring of the input clutch 21, and the output shaft system 30 includes an output gear 31, which is meshed and connected with the main transmission gear shaft 23 to realize the transmission connection between the input shaft system 20 and the output shaft system 30. In addition, the main transmission gear shaft 23 is connected to the input oil cylinder 22 through the clutch, and the input clutch 21 can realize the effect of the engagement or disengagement of the two, so that when the input clutch 21 is engaged, the input oil cylinder 22 is connected to the main transmission gear shaft 23, and when the input clutch 21 is disengaged, the input oil cylinder 22 and the main transmission gear shaft 23 are disconnected.

[0044] Furthermore, the output shaft system 30 also includes an output shaft 32, the output gear 31 is disposed on the output shaft 32, and the output shaft 32 is connected to the propeller to achieve the output of power of the dual-speed ratio marine gearbox.

[0045] Optionally, a thrust bearing 33 is further provided between the output shaft 32 and the housing 10 to support the output shaft 32 .

[0046] Of course, bearings are also provided between the shafts of other shaft systems and the box body 10 to achieve the fixation and support of each shaft system by the box body 10, which will not be described in detail here.

[0047] In this embodiment, the input shaft system 20 also includes a PTH gear 24, which is arranged on the main drive gear shaft 23. The PTH shaft system 50 includes a PTH hollow gear shaft 52, which is connected to the outer ring of the PTH clutch 51. The PTH hollow gear shaft 52 is meshed with the PTH gear 24 to achieve a transmission connection between the input shaft system 20 and the PTH shaft system 50, thereby achieving power transmission in the low-speed cruise mode and the PTH mode.

[0048] Furthermore, the input shaft system 20 also includes a PTO gear 25, which is arranged on the input cylinder 22. The PTO shaft system 40 includes a PTO hollow gear shaft 42, which is connected to the outer ring of the PTO clutch 41. The PTO hollow gear shaft 42 and the PTO gear 25 are meshed and connected to realize the transmission connection between the input shaft system 20 and the PTO shaft system 40, thereby realizing the transmission of power in the hybrid power output mode and the low-speed cruising mode.

[0049] Furthermore, the PTH shaft system 50 also includes a first transmission shaft, which is connected to the inner ring of the PTH clutch 51, and the first transmission shaft can be connected to the shaft-belt generator; when in use, when power is transmitted to the first transmission shaft through the PTH clutch 51, the shaft-belt generator can be driven to generate electricity; and when power is transmitted from the shaft-belt generator to the PTH hollow gear shaft 52 through the PTH clutch 51, the power output of the shaft-belt generator can be realized.

[0050] Furthermore, the PTO shaft system 40 also includes a second transmission shaft, which is connected to the inner ring of the PTO clutch 41, and the second transmission shaft is connected to the first transmission shaft; when in use, when power is transmitted to the second transmission shaft through the PTO clutch 41 and then to the first transmission shaft, the drive of the shaft-belt generator for power generation can be realized; and when power is transmitted to the PTH clutch 51 through the PTO clutch 41 through the second transmission shaft and the first transmission shaft, and then transmitted to the PTO hollow gear shaft 42, the power output of the second speed ratio can be achieved.

[0051] Specifically, the first transmission shaft and the second transmission shaft can be connected via a gear pair to achieve transmission connection between the two, so that when the second transmission shaft rotates, it can also drive the first transmission shaft to rotate, and then drive the shaft-belt generator to generate electricity.

[0052] Preferably, the PTO shaft system 40 and the PTH shaft system 50 are coaxially arranged so that the two are connected in transmission. That is, the first transmission shaft and the second transmission shaft are coaxially connected and merged into a connecting shaft 60, the PTO hollow gear shaft 42 is connected to the connecting shaft 60 through the PTO clutch 41, and the PTH hollow gear shaft 52 is connected to the connecting shaft 60 through the PTH clutch 51, thereby realizing the transmission connection between the PTO shaft system 40 and the PTH, and the connection between the PTH shaft system 50 and the PTO shaft system 40 and the shaft generator. In addition, such an arrangement also eliminates part of the structure, making the dual-speed ratio marine gearbox structure more compact, improving the volume utilization rate, and reducing the volume of the dual-speed ratio marine gearbox.

[0053] Please refer to Figures 2 to 4 In this embodiment, the dual-speed ratio marine gearbox also includes an oil circuit system, which is arranged in the box body 10. The oil circuit system includes a lubricating oil supply circuit 72 and a hydraulic oil supply circuit 71. The lubricating oil supply circuit 72 is used to supply lubricating oil to the input shaft system 20, the output shaft system 30, the PTO shaft system 40 and the PTH shaft system 50. The hydraulic oil supply circuit 71 is used to supply hydraulic oil to the input shaft system 20, the output shaft system 30, the PTO shaft system 40 and the PTH shaft system 50, thereby realizing the lubrication of various structures in the dual-speed ratio marine gearbox.

[0054] Specifically, the hydraulic oil supply circuit 71 includes a first circuit 7101 and a second circuit 7102, both of which are connected to the hydraulic oil gear pump 711. The first circuit 7101 can selectively supply hydraulic oil to the input clutch 21 or the PTH clutch 51, and the second circuit 7102 is used to supply hydraulic oil to the PTO clutch 41. This arrangement prevents the hydraulic oil gear pump 711 from supplying hydraulic oil to the input clutch 21 and the PTH clutch 51 at the same time, so that the input clutch 21 and the PTH clutch 51 do not work at the same time, avoiding the situation where dual power sources transmit power.

[0055] Optionally, the hydraulic oil supply circuit 71 is provided with a reversing solenoid valve 712 to achieve on-off control of each circuit in the hydraulic oil supply circuit 71 .

[0056] Specifically, the reversing solenoid valve 712 can be divided into a first reversing valve and a second reversing valve.

[0057] More specifically, the first circuit 7101 is provided with a first reversing valve, which has two channels, one of which is connected to the input clutch 21, and the other is connected to the PTH clutch 51. The first reversing valve can switch the connection status of the two channels with the hydraulic oil gear pump 711, so that the input clutch 21 and the PTH clutch 51 do not work at the same time.

[0058] More specifically, the hydraulic oil supply circuit 71 is further provided with a plurality of second reversing valves to realize the on-off control of other circuits in the hydraulic oil supply circuit 71 and between other circuits.

[0059] Furthermore, a hydraulic oil filter 713 is provided on the hydraulic oil supply circuit 71 for filtering the hydraulic oil supplied to the input shaft system 20 , the output shaft system 30 , the PTO shaft system 40 and the PTH shaft system 50 .

[0060] In addition, the hydraulic oil supply circuit 71 is further provided with a pilot relief valve 714 for adjusting the oil pressure of the hydraulic oil supplied to the input shaft system 20 , the output shaft system 30 , the PTO shaft system 40 and the PTH shaft system 50 .

[0061] Furthermore, the hydraulic oil supply circuit 71 is also connected to a hydraulic oil electric backup pump 715 to realize backup of the hydraulic oil supply, so that when the hydraulic oil gear pump 711 fails, hydraulic oil can be supplied to the input shaft system 20, the output shaft system 30, the PTO shaft system 40 and the PTH shaft system 50 through the hydraulic oil electric backup pump 715.

[0062] Specifically, the lubricating oil supply circuit 72 is provided with a lubricating oil gear pump 721 for supplying lubricating oil to the input shaft system 20 , the output shaft system 30 , the PTO shaft system 40 and the PTH shaft system 50 .

[0063] Specifically, the lubricating oil supply circuit 72 is provided with a lubricating oil filter 722 for filtering the lubricating oil supplied to the input shaft system 20 , the output shaft system 30 , the PTO shaft system 40 and the PTH shaft system 50 .

[0064] Specifically, the lubricating oil supply circuit 72 is provided with a lubricating oil cooler 723 for cooling the lubricating oil supplied to the input shaft system 20 , the output shaft system 30 , the PTO shaft system 40 and the PTH shaft system 50 .

[0065] More specifically, the lubricating oil supply circuit 72 is also provided with a lubricating oil electric standby pump 724 to realize the backup of the lubricating oil supply, so that when the lubricating oil gear pump 721 fails, the lubricating oil can be supplied to the input shaft system 20, the output shaft system 30, the PTO shaft system 40 and the PTH shaft system 50 through the lubricating oil electric standby pump 724.

[0066] Specifically, the oil circuit system also includes an instrument panel 73 and a machine-side control box 74 to monitor and control the hydraulic oil supply circuit 71 and the lubricating oil supply circuit 72, thereby facilitating operators to monitor the oil circuit system.

[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. Dual-speed ratio marine gearbox, characterized in that: It comprises a housing (10), an input shaft system (20), an output shaft system (30), a PTO shaft system (40) and a PTH shaft system (50), wherein the input shaft system (20), the output shaft system (30), the PTO shaft system (40) and the PTH shaft system (50) are all arranged in the housing (10); The input shaft system (20) and the PTO shaft system (40) can both be connected to a diesel engine, the input shaft system (20) is respectively connected to the output shaft system (30) and the PTH shaft system (50) by transmission, the PTO shaft system (40) is connected to the PTH shaft system (50) by transmission, and the PTH shaft system (50) and the PTO shaft system (40) can both be connected to a shaft-belt generator; The input shaft system (20) is provided with an input clutch (21), the PTO shaft system (40) is provided with a PTO clutch (41), and the PTH shaft system (50) is provided with a PTH clutch (51).

2. The dual-speed ratio marine gearbox according to claim 1, characterized in that: The input shaft system (20) comprises an input oil cylinder (22), the output end of the input oil cylinder (22) is connected to the outer ring of the input clutch (21), and the input end of the input oil cylinder (22) can be connected to the diesel engine.

3. The dual-speed ratio marine gearbox according to claim 2, characterized in that: The input shaft system (20) further comprises a main transmission gear shaft (23), wherein the main transmission gear shaft (23) is connected to the inner ring of the input clutch (21), and the output shaft system (30) comprises an output gear (31), wherein the output gear (31) is meshedly connected to the main transmission gear shaft (23) to achieve transmission connection between the input shaft system (20) and the output shaft system (30).

4. The dual-speed ratio marine gearbox according to claim 3, characterized in that: The input shaft system (20) further comprises a PTH gear (24), wherein the PTH gear (24) is arranged on the main transmission gear shaft (23), and the PTH shaft system (50) comprises a PTH hollow gear shaft (52), wherein the PTH hollow gear shaft (52) is connected to the outer ring of the PTH clutch (51), and the PTH hollow gear shaft (52) is meshedly connected with the PTH gear (24) to realize transmission connection between the input shaft system (20) and the PTH shaft system (50).

5. The dual-speed ratio marine gearbox according to claim 4, characterized in that: The input shaft system (20) further comprises a PTO gear (25), wherein the PTO gear (25) is arranged on the input oil cylinder (22), and the PTO shaft system (40) comprises a PTO hollow gear shaft (42), wherein the PTO hollow gear shaft (42) is connected to the outer ring of the PTO clutch (41), and the PTO hollow gear shaft (42) and the PTO gear (25) are meshedly connected to realize the transmission connection between the input shaft system (20) and the PTO shaft system (40).

6. The dual-speed ratio marine gearbox according to claim 5, characterized in that: The PTH shaft system (50) further comprises a first transmission shaft, the first transmission shaft being connected to the inner ring of the PTH clutch (51), and the first transmission shaft being connectable to the shaft generator; The PTO shaft system (40) further comprises a second transmission shaft, wherein the second transmission shaft is connected to the inner ring of the PTO clutch (41), and the second transmission shaft is transmission-connected to the first transmission shaft.

7. The dual-speed ratio marine gearbox according to claim 1, characterized in that: The PTO shaft system (40) and the PTH shaft system (50) are coaxially arranged so that the two are transmission-connected.

8. The dual-speed ratio marine gearbox according to claim 1, characterized in that: The invention also includes an oil circuit system, wherein the oil circuit system is arranged in the housing (10), and the oil circuit system includes a lubricating oil supply circuit (72) and a hydraulic oil supply circuit (71). The lubricating oil supply circuit (72) is used to supply lubricating oil to the input shaft system (20), the output shaft system (30), the PTO shaft system (40) and the PTH shaft system (50), and the hydraulic oil supply circuit (71) is used to supply hydraulic oil to the input shaft system (20), the output shaft system (30), the PTO shaft system (40) and the PTH shaft system (50).

9. The dual-speed ratio marine gearbox according to claim 8, characterized in that: The hydraulic oil supply circuit (71) comprises a first circuit (7101) and a second circuit (7102). The first circuit (7101) and the second circuit (7102) are both connected to a hydraulic oil gear pump (711). The first circuit (7101) can selectively supply hydraulic oil to the input clutch (21) or the PTH clutch (51). The second circuit (7102) is used to supply hydraulic oil to the PTO clutch (41).

10. The dual-speed ratio marine gearbox according to claim 9, characterized in that: The first circuit (7101) is provided with a first reversing valve, which has two channels, one of which is connected to the input clutch (21) and the other is connected to the PTH clutch (51). The first reversing valve can switch the connection state between the two channels and the hydraulic oil gear pump (711).

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