Two-stage transmission marine gearbox convenient to disassemble, assemble and maintain and disassembling method of two-stage transmission marine gearbox

Abstract

According to the secondary transmission marine gearbox convenient to disassemble, assemble and maintain and the disassembling method thereof, the secondary transmission marine gearbox comprises a shell, an input shaft component, a transmission shaft component, an intermediate shaft component and an output shaft component, and on the side close to the power input end, the input shaft component is connected with the shell through a first tapered roller bearing; the transmission shaft component is connected with the shell through a second tapered roller bearing, the middle shaft component is connected with the shell through a third tapered roller bearing, the output shaft component is connected with the shell through a fourth tapered roller bearing, an integrated rear cover is detachably connected to the bearing seat plate, and an integrated oil way is integrally formed on the integrated rear cover. The main oil pump supplies oil to the input shaft component and the transmission shaft component through the integrated oil way. The shaft part can be easily and horizontally pulled out through the first disassembly and assembly hole and the second disassembly and assembly hole, operation such as disassembly of all screws, disassembly of a pipeline and lifting of a shell is not needed, disassembly and assembly are convenient and fast, and meanwhile the machining difficulty and cost are greatly reduced through the whole box body structure.

Description

Technical Field

[0001] This invention relates to the field of marine propulsion system technology, and in particular to a two-stage transmission marine gearbox that is easy to disassemble and maintain, and a method for disassembling the same. Background Technology

[0002] refer to Figures 1-2 Marine gearboxes have a high gear ratio, requiring a two-stage gear reduction to achieve the desired speed ratio. This necessitates the addition of intermediate components. To address the challenges of disassembling and assembling these intermediate components and maintaining the gearbox, current two-stage marine gearboxes primarily employ a split structure consisting of an upper, middle, and lower housing, along with input, transmission, intermediate, and output components. The intermediate components utilize self-aligning bearings and cylindrical roller bearings. Consequently, replacing internal parts requires lifting the entire gearbox out, separating the upper, middle, and lower housings for repair, and then reassembling it to align the gearbox's three alignment lines. This process is inconvenient, time-consuming, and labor-intensive, increasing the difficulty of maintenance.

[0003] Referring to Chinese patent application document CN106122452B, a lightweight heavy-duty marine gearbox is disclosed, belonging to the field of transmission devices for marine auxiliary power output. It includes a gearbox housing, within which are an input shaft assembly, a transmission shaft assembly, and an output shaft assembly. The input shaft assembly meshes with the transmission shaft assembly, and the output shaft assembly meshes with both the input shaft assembly and the transmission shaft assembly. Although this marine gearbox optimizes its internal structure for easier disassembly and assembly, disassembly still requires removing the rear cover and the complex external piping on the gearbox housing one by one, followed by reinstallation, making the operation complex and time-consuming. Furthermore, the disassembly and assembly of the output shaft assembly remains relatively complex. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the purpose of this invention is to provide a two-stage transmission marine gearbox and its disassembly method that are easy to disassemble and maintain. This method eliminates the need to disassemble the gearbox body or deal with complex oil pipelines. After disassembling the integrated rear cover and bearing seat plate, each shaft component can be disassembled or installed laterally, making the gearbox easy to disassemble and assemble, saving time and effort.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A two-stage marine gearbox with easy disassembly, assembly, and maintenance includes a housing, an input shaft assembly, a drive shaft assembly, an intermediate shaft assembly, and an output shaft assembly. The input shaft assembly is drively connected to the drive shaft assembly, and the intermediate shaft assembly is drively connected to the output shaft assembly. The intermediate shaft assembly can be drively connected to both the input shaft assembly and the drive shaft assembly. A first clutch assembly is provided on the input shaft assembly, and a second clutch assembly is provided on the drive shaft assembly. By controlling the engagement and disengagement of the first and second clutch assemblies respectively, the intermediate shaft assembly can have different rotation directions. The rotation direction of the intermediate shaft assembly when drively connected to the input shaft assembly is opposite to its rotation direction when drively connected to the drive shaft assembly. On the side closer to the power input end, the input shaft assembly... The input shaft assembly is connected to the housing via a first tapered roller bearing, with the outer ring of the first tapered roller bearing having an interference fit with the housing and the inner ring of the first tapered roller bearing having a clearance fit with the input shaft assembly. The drive shaft assembly is connected to the housing via a second tapered roller bearing, with the outer ring of the second tapered roller bearing having an interference fit with the housing and the inner ring of the second tapered roller bearing having a clearance fit with the drive shaft assembly. The intermediate shaft assembly is connected to the housing via a third tapered roller bearing, with the outer ring of the third tapered roller bearing having an interference fit with the housing and the inner ring of the third tapered roller bearing having a clearance fit with the intermediate shaft assembly. The output shaft assembly is connected to the housing via a fourth tapered roller bearing, with the outer ring of the fourth tapered roller bearing having an interference fit with the housing and the inner ring of the fourth tapered roller bearing having a clearance fit with the output shaft assembly.

[0007] On the side away from the power input end, the housing includes a box, a bearing seat plate, and an output rear cover. The box is provided with a first disassembly hole and a second disassembly hole. During disassembly and assembly, the input shaft component and the transmission shaft component can be moved out or installed through the first disassembly hole. The intermediate shaft in the intermediate shaft component and the intermediate shaft transmission gear that meshes with the output shaft component can be moved out or installed through the first disassembly hole. The output shaft of the output shaft component can be moved out or installed through the second disassembly hole. The bearing seat plate and the output rear cover are detachably connected to the box. The input shaft component is connected to the bearing seat plate through a fifth tapered roller bearing. The transmission shaft component is connected to the bearing seat plate through a sixth tapered roller bearing. The intermediate shaft component is connected to the bearing seat plate through a seventh tapered roller bearing. The output shaft component is connected to the output rear cover through an eighth tapered roller bearing. An integrated rear cover is detachably connected to the bearing seat plate. An integrated oil circuit is integrally formed on the integrated rear cover. The main oil pump supplies oil to the input shaft component and the transmission shaft component through the integrated oil circuit.

[0008] In some embodiments, the integrated rear cover has a first shaft hole that mates with the outer peripheral shape of the input shaft in the input shaft assembly, and a second shaft hole that mates with the outer peripheral shape of the drive shaft in the drive shaft assembly. The inner wall of the first shaft hole mates with the outer peripheral side of the input shaft. An oil inlet for the forward working oil circuit is provided on the outer peripheral side of the input shaft, so that the first oil inlet on the inner wall of the first shaft hole is connected to the forward working oil circuit in the input shaft. The inner wall of the second shaft hole mates with the outer peripheral side of the drive shaft. An oil inlet for the reverse working oil circuit is provided on the outer peripheral side of the drive shaft, so that the second oil inlet on the inner wall of the second shaft hole is connected to the reverse working oil circuit in the input shaft. The first oil inlet and the second oil inlet are respectively connected to the working oil port of the main oil pump through a control valve.

[0009] In some embodiments, the integrated rear cover includes a cover plate portion and a hollow first protrusion portion. The hollow portion of the first protrusion portion is a second shaft hole. The end of the first protrusion portion is provided with an oil suction pump inlet hole and an oil suction pump outlet hole, which are connected. The outer side wall of the first protrusion portion has an oil suction pump suction hole connected to the oil suction pump, an oil filter inlet hole connected to the oil filter input end, and an oil filter outlet hole connected to the oil filter output end. The oil suction pump suction hole is connected to the oil suction pump inlet hole, and the oil suction pump outlet hole is connected to the oil filter inlet hole. The oil filter is fixed on the integrated rear cover, and the oil filter outlet hole is connected to the main oil pump. The oil suction pump is used to pump oil from the bottom of the tank into the oil suction pump suction hole.

[0010] In some embodiments, the integrated rear cover is further provided with a second protrusion for connecting a control system component. The control system component houses a control valve and a control valve controller for controlling the control valve. The control system component is detachably connected to the second protrusion. The second protrusion has a main oil pump inlet port inside. The input end of the main oil pump inlet port is connected to the main oil pump, and the output end of the main oil pump inlet port is connected to the working oil circuit and the main lubrication oil circuit. The second protrusion has a control valve inlet port connected to the main oil pump inlet port on the side near the control system component. Oil enters the control system component from the control valve inlet port. The second protrusion also has a forward working oil port and a reverse working oil port inside. One end of the forward working oil port is connected to the forward output end of the control system component, and the other end is connected to the forward working oil circuit. One end of the reverse working oil port is connected to the reverse output end of the control system component, and the other end is connected to the reverse working oil circuit.

[0011] In some embodiments, the inner wall of the first shaft hole and the inner wall of the second shaft hole are connected through a first lubricating oil passage, the first lubricating oil passage is connected to the oil inlet of the main oil pump, a cavity is formed between the inner wall of the first shaft hole and the front end of the input shaft, and the front end of the input shaft is provided with an oil inlet of the lubricating oil passage inside the input shaft. The inner wall of the second shaft hole and the front end of the transmission shaft are connected to a cavity, and the front end of the transmission shaft is provided with an oil inlet of the lubricating oil passage inside the transmission shaft.

[0012] In some embodiments, the output ports of the lubrication circuit in the input shaft include an oil distribution port leading to the space between the first tapered roller bearing and the housing, an oil distribution port leading to the space between the fifth tapered roller bearing and the integrated rear cover, and an oil distribution port leading to the inner wall of the inner ring of the first tapered roller bearing. The output ports of the lubrication circuit in the drive shaft include an oil distribution port leading to the space between the second tapered roller bearing and the housing, an oil distribution port leading to the space between the sixth tapered roller bearing and the integrated rear cover, and an oil distribution port leading to the inner wall of the inner ring of the second tapered roller bearing.

[0013] In some embodiments, the intermediate shaft in the intermediate shaft assembly is connected to the housing via a third tapered roller bearing. A first oil sump is provided between the third tapered roller bearing and the housing. The intermediate shaft has a drain hole at its end, and the side wall of the intermediate shaft has an oil port leading to the inner ring of the third tapered roller bearing. This oil port communicates with the drain hole. The central protrusion of the first oil sump leads into the drain hole to concentrate and introduce the oil splashed from the third tapered roller bearing into the drain hole. The output shaft in the output shaft assembly is connected to the housing via a fourth tapered roller bearing. A second oil sump is provided between the fourth tapered roller bearing and the housing. The output shaft has a drain hole at its end, and the side wall of the output shaft has an oil port leading to the inner ring of the fourth tapered roller bearing. This oil port communicates with the drain hole. The central protrusion of the second oil sump leads into the drain hole to concentrate and introduce the oil splashed from the third tapered roller bearing into the drain hole.

[0014] In some embodiments, the input shaft component includes an input shaft and a drive gear assembly, a first clutch assembly, and a right-hand drive gear sequentially disposed on the input shaft. The right-hand drive gear is fixedly connected to the input shaft, the drive gear assembly is connected to the input shaft via a bearing, and both the right-hand drive gear and the drive gear assembly are fixedly connected to the first clutch assembly. When the first clutch assembly is engaged, the drive gear assembly can engage with the right-hand drive gear and rotate synchronously. The right-hand drive gear is disposed near the first disassembly hole.

[0015] The drive shaft assembly includes a drive shaft and a drive gear assembly, a second clutch assembly, and a left-hand drive gear arranged sequentially on the drive shaft. The left-hand drive gear is fixedly connected to the input shaft. The drive gear assembly is connected to the drive shaft through a bearing. Both the left-hand drive gear and the drive gear assembly are fixedly connected to the second clutch assembly. When the second clutch assembly is engaged, the drive gear assembly can engage with the left-hand drive gear and rotate synchronously. The left-hand drive gear is located near the first disassembly hole.

[0016] The intermediate shaft assembly includes an intermediate shaft, an intermediate shaft large gear and an intermediate shaft drive gear fixedly connected to the intermediate shaft, and the first clutch assembly and the second clutch assembly are located closer to the first disassembly hole than the intermediate shaft large gear.

[0017] The output shaft assembly includes an output shaft and a driven gear fixedly connected to the output shaft;

[0018] The right-hand drive gear meshes with the left-hand drive gear for transmission. The large gear on the intermediate shaft meshes with both the drive gear assembly and the transmission gear assembly for transmission. The transmission gear on the intermediate shaft meshes with the driven gear for transmission.

[0019] In some embodiments, the major diameter ends of the inner rings of the first, second, third, and fourth tapered roller bearings are arranged facing the first disassembly hole, and the minor diameter ends of the inner rings of the fifth, sixth, seventh, and eighth tapered roller bearings are arranged facing the first disassembly hole.

[0020] This invention also provides a method for disassembling a two-stage marine gearbox, applicable to the aforementioned two-stage marine gearbox which is easy to disassemble and maintain, comprising the following steps:

[0021] S1: Remove the integrated rear cover, output rear cover, and bearing seat plate;

[0022] S2: Pull out the input shaft assembly and transmission shaft assembly by moving them through the first disassembly hole;

[0023] S3: Pressurize the intermediate shaft large gear in the intermediate shaft assembly that is connected to the input shaft assembly and the transmission shaft assembly to separate it from the intermediate shaft. Move and pull out the other components on the input shaft assembly except for the intermediate shaft large gear from the first disassembly hole, and then take out the intermediate shaft large gear.

[0024] S4: Pressurize the driven gear in the output shaft assembly that is connected to the intermediate shaft assembly to separate it from the output shaft. Then, slide and pull out the other components in the output shaft assembly except for the driven gear from the second disassembly hole. Finally, remove the driven gear.

[0025] The present invention has the following beneficial effects:

[0026] This invention divides the housing of a two-stage marine gearbox into three layers: an outer shell, a bearing housing plate, and an integrated rear cover, without any splitting. The integrated oil circuit is integrally formed on the integrated rear cover. The main oil pump supplies oil to the input shaft component and the transmission shaft component through the integrated oil circuit. The pipeline and internal structure can be separated by removing the integrated rear cover, eliminating the need to deal with complex external oil pipelines. The bearing housing plate can be removed to separate the supporting bearing from the shaft, making operation convenient. Furthermore, each shaft component has a clearance fit with the shaft on the side near the power input end, allowing the input shaft component, transmission shaft component, intermediate shaft component, and output shaft component to be easily moved and pulled out through the first and second disassembly holes, respectively, without the need to remove all screws, disassemble pipelines, or lift the housing. The same operation applies when installing each shaft component, making the disassembly and assembly of the two-stage marine gearbox convenient and quick. At the same time, the overall housing structure of this invention greatly reduces the processing difficulty and cost. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of a two-stage transmission marine gearbox in the prior art.

[0028] Figure 2 This is a schematic diagram of the structure of a two-stage transmission marine gearbox in the prior art.

[0029] Figure 3 This is one of the perspective views of the two-stage transmission marine gearbox of the present invention.

[0030] Figure 4 This is the second perspective view of the two-stage transmission marine gearbox of the present invention.

[0031] Figure 5 This is one of the perspective views of the housing of the present invention.

[0032] Figure 6 This is a second perspective view of the housing of the present invention.

[0033] Figure 7 This is the third perspective view of the housing of the present invention.

[0034] Figure 8 This is the fourth perspective view of the housing of the present invention.

[0035] Figure 9 This is a cross-sectional view of the housing of the present invention.

[0036] Figure 10 This is a cross-sectional view of the two-stage transmission marine gearbox of the present invention.

[0037] Figure 11 This is one of the 3D renderings of the integrated back cover.

[0038] Figure 12 This is the second 3D view of the integrated back cover.

[0039] Figure 13 This is the third 3D view of the integrated back cover.

[0040] Figure 14 This is a schematic diagram of the lubrication circuit structure of the integrated back cover.

[0041] Figure 15 This is a schematic diagram of the reversing oil circuit structure of the integrated rear cover.

[0042] Figure 16 This is a schematic diagram of the oil circuit structure for the integrated rear cover.

[0043] Figure 17 This is a structural schematic diagram of the input shaft component.

[0044] Figure 18 This is a structural schematic diagram of the drive shaft component.

[0045] Figure 19 This is a structural schematic diagram of the intermediate shaft component.

[0046] Figure 20 This is a structural schematic diagram of the output shaft component.

[0047] Explanation of reference numerals in the attached figures:

[0048] 10. High-elasticity coupling; 20. Input shaft assembly; 201. Input shaft; 202. Drive gear assembly; 203. Coupling; 204. Right-hand drive gear; 200. First clutch assembly; 205. First clutch seat; 206. Piston; 207. Spring; 208. Spring support plate; 209. Outer friction plate; 210. Inner friction plate; 211. Pressure plate; 215. First tapered roller bearing; 216. Needle roller bearing; 217. Ninth tapered roller bearing; 218. Fifth tapered roller bearing;

[0049] 30. Drive shaft assembly; 301. Drive shaft; 302. Left-hand drive gear; 303. Drive gear assembly; 300. Second clutch assembly; 315. Second tapered roller bearing; 317. Tenth tapered roller bearing; 318. Sixth tapered roller bearing;

[0050] 40. Intermediate shaft assembly; 401. Intermediate shaft; 402. Intermediate shaft large gear; 403. Third tapered roller bearing; 404. Seventh tapered roller bearing; 405. Intermediate shaft drive gear; 406. First oil sump; 407. Hydraulic pressure hole for disassembly and assembly;

[0051] 50. Output shaft assembly; 501. Output shaft; 502. Driven gear; 503. Output flange; 504. Fourth tapered roller bearing; 505. Eighth tapered roller bearing; 506. Second oil sump;

[0052] 60. Control system components; 70. Housing; 701. Box body; 7011. First disassembly / assembly hole; 7012. Second disassembly / assembly hole; 702. Bearing seat plate; 703. Integrated rear cover; 7031. First protrusion; 70311. Oil suction pump inlet; 70312. Oil suction pump outlet; 70313. Oil suction pump suction hole; 70314. Oil filter inlet; 70315. Oil filter outlet; 7032. First shaft hole; 7033. Second shaft hole; 7034. Second protrusion; 70341. Main oil pump inlet; 70342. Control valve inlet; 70343. Forward working oil hole; 70344. Reverse working oil hole; 7035. Cover plate; 704. Output rear cover; 705. Cover; 706. Top cover plate;

[0053] 80. Oil filter; 90. Main oil pump; 100. Suction pump; 110. Main lubrication circuit; 1101. First lubrication circuit; 120. Reverse working oil circuit; 130. Forward working oil circuit. Detailed Implementation

[0054] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0055] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be used for fixing, coupling, or communication.

[0056] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0057] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0058] refer to Figures 3-10The present invention relates to a two-stage marine gearbox with convenient disassembly, assembly, and maintenance, comprising a housing 70, an input shaft assembly 20, a transmission shaft assembly 30, an intermediate shaft assembly 40, and an output shaft assembly 50. The input shaft assembly 20 is drive-connected to the transmission shaft assembly 30, and the intermediate shaft assembly 40 is drive-connected to the output shaft assembly 50. The intermediate shaft assembly 40 can be drive-connected to both the input shaft assembly 20 and the transmission shaft assembly 30. The input shaft assembly 20 is provided with a first clutch assembly 200, and the transmission shaft assembly 30 is provided with a second clutch assembly 300. By controlling the engagement and disengagement of the first clutch assembly 200 and the second clutch assembly 300 respectively, the intermediate shaft assembly 40 can have different rotation directions. The rotation direction of the intermediate shaft assembly 40 when drive-connected to the input shaft assembly 20 is opposite to that when drive-connected to the transmission shaft assembly 30. On the side near the power input end, the input shaft assembly 20 is connected to the housing 70. The drive shaft assembly 30 is connected to the housing 70 via a first tapered roller bearing 215, the outer ring of which is interference-fitted with the housing 70, and the inner ring of which is clearance-fitted with the input shaft assembly 20. The drive shaft assembly 30 is connected to the housing 70 via a second tapered roller bearing 315, the outer ring of which is interference-fitted with the housing 70, and the inner ring of which is clearance-fitted with the drive shaft assembly 30. The intermediate shaft assembly 40 is connected to the housing 70 via a third tapered roller bearing 403, the outer ring of which is interference-fitted with the housing 70, and the inner ring of which is clearance-fitted with the intermediate shaft assembly 40. The output shaft assembly 50 is connected to the housing 70 via a fourth tapered roller bearing 504, the outer ring of which is interference-fitted with the housing 70, and the inner ring of which is clearance-fitted with the output shaft assembly 50.

[0059] On the side away from the power input end, the housing 70 includes a box 701, a bearing seat plate 702, and an output rear cover 704. The box 701 has a first disassembly hole 7011 and a second disassembly hole 7012. During disassembly and assembly, the input shaft assembly 20 and the transmission shaft assembly 30 can be moved out or installed through the first disassembly hole 7011. The intermediate shaft 401 in the intermediate shaft assembly 40 and the intermediate shaft transmission gear 405 meshing with the output shaft assembly 50 can be moved out or installed through the first disassembly hole 7011. The output shaft 501 of the output shaft assembly 50 can be moved out or installed through the second disassembly hole 7012. The bearing seat plate 702 and... The output rear cover 704 is detachably connected to the housing 701. The input shaft component 20 is connected to the bearing seat plate 702 via the fifth tapered roller bearing 218. The drive shaft component 30 is connected to the bearing seat plate 702 via the sixth tapered roller bearing 318. The intermediate shaft component 40 is connected to the bearing seat plate 702 via the seventh tapered roller bearing 404. The output shaft component 50 is connected to the output rear cover 704 via the eighth tapered roller bearing 505. An integrated rear cover 703 is detachably connected to the bearing seat plate 702. An integrated oil circuit is integrally formed on the integrated rear cover 703. The main oil pump 90 supplies oil to the input shaft component 20 and the drive shaft component 30 through the integrated oil circuit.

[0060] In this embodiment, the shaft component is connected to the bearing housing plate via a tapered roller bearing, meaning the bearing housing plate fixes the outer ring of the tapered roller bearing, and the shaft in the shaft component fixes the inner ring of the tapered roller bearing.

[0061] like Figure 1 and Figure 2As shown, a conventional gearbox is split into two parts, with the clutch positioned at the left end via the gearbox input shaft and drive shaft components. Two separate small covers, one for the input and one for the drive shaft, are used for sealing. Separate covers are also provided at the front and rear of the intermediate shaft component for easy disassembly. In this type of gearbox, disassembly requires unscrewing the bolts connecting the upper and middle upper gearboxes, then lifting the upper and middle upper gearboxes sequentially to remove the input shaft, drive shaft, and intermediate shaft components for parts replacement. Furthermore, the upper gearbox typically houses hydraulic systems and piping; lifting the upper gearbox necessitates completely disassembling the hydraulic lines, making the process extremely cumbersome. In this embodiment, the gearbox is divided into three layers: the outer shell, the bearing housing plate 702, and the integrated rear cover 703. All three are integral structures and are not disassembled. The piping can be separated from the internal structure by removing the integrated rear cover 703. Then, by removing the bearing housing, the outer ring of the bearing is brought out, eliminating horizontal restriction at the end near the first disassembly hole 7011. The bearing at the other end has a clearance fit with the input shaft component and the transmission shaft component, also without horizontal restriction, allowing the shaft component to be horizontally removed. The same principle applies to removing the intermediate shaft component and the output shaft component. However, since both have large gears on their shafts, directly pulling out the outer shell horizontally would obstruct the large gears. Therefore, the large intermediate gear can be hydraulically ejected first before the shaft and other components can be smoothly removed. This embodiment allows for the replacement of friction plates and high-elasticity components without moving the main unit and gearbox by sliding the input shaft component, transmission shaft component, intermediate shaft component, and output shaft component out or in. In this embodiment, the disassembly holes are divided into a first disassembly hole 7011 and a second disassembly hole 7012. The size of the two holes allows for easy removal of each component while maintaining the stability of the housing. Furthermore, the integrated housing structure of this embodiment significantly reduces processing difficulty and cost. The integrated oil circuit is integrally formed on the integrated rear cover. The main oil pump supplies oil to the input shaft component and the drive shaft component through the integrated oil circuit. By removing the integrated rear cover, the pipeline can be separated from the internal structure, eliminating the need to handle complex external oil pipelines, making disassembly and assembly convenient and quick.

[0062] refer to Figures 11-13In this embodiment and some other embodiments, the integrated rear cover 703 has a first shaft hole 7032 that can mate with the outer peripheral shape of the input shaft 201 in the input shaft component 20, and a second shaft hole 7033 that mates with the outer peripheral shape of the transmission shaft 301 in the transmission shaft component 30. The inner sidewall of the first shaft hole 7032 mates with the outer peripheral side of the input shaft 201. An oil inlet of the traveling oil passage 130 is provided on the outer peripheral side of the input shaft 201, so that the first shaft hole The first oil inlet hole on the inner wall of the 7032 is connected to the forward working oil passage 130 in the input shaft. The inner wall of the second shaft hole 7033 mates with the outer periphery of the drive shaft. The outer periphery of the drive shaft 301 is provided with an oil inlet for the reverse working oil passage 120, so that the second oil inlet hole on the inner wall of the second shaft hole 7033 is connected to the reverse working oil passage 120 in the input shaft 201. The first oil inlet hole and the second oil inlet hole are respectively connected to the working oil port of the main oil pump 90 through the control valve. In this embodiment, by integrating the first oil inlet hole and the second oil inlet hole on the integrated rear cover 703 to provide working oil to the outer periphery of the shaft in the input shaft component 20 and the drive shaft component 30, the oil circuit is simple and reliable, and the structure is compact. In this embodiment, the first oil inlet hole on the inner wall of the first shaft hole 7032 is connected to the forward working oil passage in the input shaft through a rotary oil supply connector, that is, the forward working oil passage 130 is connected to the forward working oil passage in the input shaft. The second oil inlet hole on the inner wall of the second shaft hole is connected to the reverse working oil passage in the input shaft through a rotary oil supply connector, that is, the reverse working oil passage 120 is connected to the reverse working oil passage in the input shaft.

[0063] refer to Figures 12-13In this embodiment and some other embodiments, the integrated rear cover 703 includes a cover plate portion 7035 and a hollow first protrusion 7031. The hollow portion of the first protrusion 7031 is a second shaft hole 7033. The end of the first protrusion 7031 is provided with an oil pump inlet hole 70311 and an oil pump outlet hole 70312, which are connected. The outer side wall of the first protrusion 7031 has an oil pump suction hole 7031 that communicates with the oil pump 100. 3. The oil filter 80 has an oil inlet 70314 connected to the input end of the oil filter 80 and an oil outlet 70315 connected to the output end of the oil filter 80. The suction port 70313 of the suction pump is connected to the oil inlet 70311 of the suction pump, and the oil outlet 70312 of the suction pump is connected to the oil inlet 70314 of the oil filter. The oil filter 80 is fixed on the integrated rear cover 703. The oil outlet 70315 of the oil filter is connected to the main oil pump 90. The suction pump 100 is used to pump oil from the bottom of the tank into the suction port 70313 of the suction pump. In this embodiment, the main oil pump 90 is placed on top of the tank, and the oil filter 80, the suction pump 100, and the inlet of the oil filter 80 on the main oil pump 90 are all located on the same side of the gearbox. In this embodiment, the oil filter 80 and its related pipes are integrated on the integrated back cover 703. The reasonable structural arrangement makes the oil filter 80 and this part of the pipeline structure compact and small in size, eliminating the need to install pipelines externally and avoiding the impact of complex pipelines on disassembly and assembly.

[0064] refer to Figures 12-13 In this embodiment and some other embodiments, the integrated back cover 703 is further provided with a second protrusion 7034 for connecting the control system component 60. The control system component 60 houses the control valve and a control valve controller. The control system component 60 is detachably connected to the second protrusion 7034. The second protrusion 7034 contains a main oil pump inlet 70341. The input end of the main oil pump inlet 70341 communicates with the main oil pump 90, and the output end of the main oil pump inlet 70341 communicates with the working oil circuit and the main lubrication oil circuit 110. The second protrusion 7034, near the control system component 60, has a control valve inlet 70342 communicating with the main oil pump inlet 70341. Oil enters the control system component 60 from the control valve inlet 70342. (Reference) Figure 15-16The second protrusion 7034 also has a forward working oil hole 70343 and a reverse working oil hole 70344 inside. One end of the forward working oil hole 70343 is connected to the forward output end of the control system component 60, and the other end is connected to the forward working oil circuit 130. One end of the reverse working oil hole 70344 is connected to the reverse output end of the control system component 60, and the other end is connected to the reverse working oil circuit 120. In this embodiment, the second protrusion 7034 is block-shaped, and valve holes can be provided at the front end and both sides of the second protrusion 7034. The control system component 60 is detachably connected to the front end of the second protrusion 7034. The main oil pump inlet 70341 is connected to the working oil circuit and the lubrication oil circuit respectively. In this embodiment, the setting of the second protrusion 7034 allows the control system component 60 to be detachably installed on the integrated rear cover 703. The reasonable structural arrangement makes the control system component 60 and this part of the pipeline structure compact and small in size, eliminating the need for external pipelines and avoiding the influence of complex pipelines on disassembly and assembly.

[0065] refer to Figure 10 and Figure 14 In this embodiment and some other embodiments, the inner wall of the first shaft hole 7032 and the inner wall of the second shaft hole 7033 are connected through the first lubricating oil passage 1101, which is connected to the main oil pump inlet 70341. A cavity is formed between the inner wall of the first shaft hole 7032 and the front end of the input shaft, and the front end of the input shaft is provided with an oil inlet for the lubricating oil passage inside the input shaft. Similarly, a cavity is formed between the inner wall of the second shaft hole 7033 and the front end of the transmission shaft, and the front end of the transmission shaft is provided with an oil inlet for the lubricating oil passage inside the transmission shaft. This arrangement allows oil passages far from the power input side to be transported to various positions via the gear shaft, thereby ensuring good lubrication of the first to fourth tapered roller bearings that are clearance-fitted with the housing. This creates an oil film between the bearings and the housing, reducing friction and preventing any impact on the gear shaft.

[0066] Specifically, refer to Figure 10In this embodiment and some other embodiments, the output ports of the lubricating oil circuit in the input shaft include an oil distribution port leading to the first tapered roller bearing 215 and the housing 701, an oil distribution port leading to the fifth tapered roller bearing 218 and the integrated rear cover 703, and an oil distribution port leading to the inner side wall of the inner ring of the first tapered roller bearing 215. The output ports of the lubricating oil circuit in the transmission shaft include an oil distribution port leading to the second tapered roller bearing 315 and the housing 701, an oil distribution port leading to the sixth tapered roller bearing 318 and the integrated rear cover 703, and an oil distribution port leading to the inner side wall of the inner ring of the second tapered roller bearing 315. In this embodiment, the input shaft and the drive gear are connected by a needle roller bearing 216, and the transmission shaft and the transmission gear are also connected by a needle roller bearing. The oil flows through the oil distribution port to the needle roller bearing, then through the inner hole of the drive gear to the inner hole of the bushing, and finally to the inner side wall of the inner ring of the first tapered roller bearing 215. The same applies to the transmission shaft. The oil distribution port in this embodiment ensures that the tapered roller bearings at both ends of the input shaft and the transmission shaft can be well lubricated, reducing friction and avoiding any impact on the gear shaft. In particular, the tapered roller bearings that are clearance-fitted with the housing can be adequately lubricated.

[0067] refer to Figure 10 and Figures 19-20 In this embodiment and some other embodiments, the intermediate shaft 401 in the intermediate shaft component 40 is connected to the housing 701 via a third tapered roller bearing 403. A first oil guide plate 406 is provided between the third tapered roller bearing 403 and the housing 701. The intermediate shaft 401 has a drainage hole at its end. The side wall of the intermediate shaft 401 is provided with an oil port leading to the inner ring of the third tapered roller bearing 403. The oil port communicates with the drainage hole. The central protrusion of the first oil guide plate 406 leads into the drainage hole to concentrate and introduce the oil splashed from the third tapered roller bearing 403 into the drainage hole. In this embodiment and some other embodiments, the output shaft 501 in the output shaft component 50 is connected to the housing 701 via a fourth tapered roller bearing 504. A second oil guide plate 506 is provided between the fourth tapered roller bearing 504 and the housing 701. The output shaft 501 has a drainage hole at its end. The side wall of the output shaft 501 is provided with an oil port leading to the inner ring of the fourth tapered roller bearing 504. The oil port communicates with the drainage hole. The central protrusion of the second oil guide plate 506 leads into the drainage hole to concentrate and introduce the oil splashed from the third tapered roller bearing 403 into the drainage hole.

[0068] In this embodiment, the intermediate shaft component 40 and the output shaft component 50 do not have internal lubrication passages. On the side away from the power input end, oil passages can be provided on the integrated rear cover 703 to lead to the seventh tapered roller bearing 404, and oil passages on the integrated rear cover 703 and the outer shell to lead to the eighth tapered roller bearing 505 to lubricate the two bearings. The oil splashed above the bearings during operation can also lubricate the bearings. However, on the side closer to the power input end, the amount of oil splashed above the bearings is less, which will result in insufficient lubrication of the bearings, high friction between the bearings and the shaft, leading to operational failures or overheating and damage to the shaft and bearings. Therefore, in this embodiment, an oil sump is used to collect the oil splashed from the third tapered roller bearing 403 and the fourth tapered roller bearing 504 and circulate it through the oil passages inside the shaft for directional lubrication. This ensures that the third tapered roller bearing 403 and the fourth tapered roller bearing 504 can be adequately lubricated by the oil splashed above them during operation, maintaining the operational stability of the gearbox.

[0069] refer to Figure 10 and Figures 18-20 In this embodiment and some embodiments, the input shaft component 20 includes an input shaft 201 and a drive gear assembly 202, a first clutch assembly 200 and a right-hand drive gear 204 sequentially arranged on the input shaft. The right-hand drive gear 204 is fixedly connected to the input shaft 201. The drive gear assembly 202 is connected to the input shaft 201 through a bearing. Both the right-hand drive gear 204 and the drive gear assembly 202 are fixedly connected to the first clutch assembly 200. When the first clutch assembly 200 is engaged, the drive gear assembly 202 can engage with the right-hand drive gear 204 and rotate synchronously. The right-hand drive gear 204 is located near the first disassembly hole 7011.

[0070] The drive shaft assembly 30 includes a drive shaft 301 and a drive gear assembly 303, a second clutch assembly 300, and a left-hand drive gear 302 sequentially arranged on the drive shaft 301. The left-hand drive gear 302 is fixedly connected to the input shaft 201. The drive gear assembly 303 is connected to the drive shaft 301 through a bearing. Both the left-hand drive gear 302 and the drive gear assembly 303 are fixedly connected to the second clutch assembly 300. When the second clutch assembly 300 is engaged, the drive gear assembly 303 can engage with the left-hand drive gear 302 and rotate synchronously. The left-hand drive gear 302 is located near the first disassembly hole 7011.

[0071] The intermediate shaft component 40 includes an intermediate shaft 401 and an intermediate shaft large gear 402 and an intermediate shaft transmission gear 405 fixedly connected to the intermediate shaft 401. The first clutch assembly 200 and the second clutch assembly 300 are located closer to the first disassembly hole 7011 than the intermediate shaft large gear 402.

[0072] The output shaft component 50 includes an output shaft 501 and a driven gear 502 fixedly connected to the output shaft 501;

[0073] The right-hand drive gear 204 meshes with the left-hand drive gear 302 for transmission. The intermediate shaft large gear 402 meshes with the drive gear assembly 202 and the transmission gear assembly 303 for transmission. The intermediate shaft transmission gear 405 meshes with the driven gear 502 for transmission.

[0074] In this embodiment, the first clutch assembly 200 and the second clutch assembly are positioned closer to the first disassembly hole 7011 than the intermediate shaft large gear 402, allowing each gear shaft to be easily pulled out. Because the outer diameter of the intermediate shaft large gear 402 is large, if it were positioned near the first disassembly hole 7011, it would obstruct the movement of the clutch assembly. If the outer diameter of the gear is adjusted to prevent the intermediate shaft large gear 402 from affecting the clutch assembly, the size of the gear would need to be greatly increased, and the volume and weight of the gearbox would also increase, resulting in a significant increase in cost. However, the component positioning in this application allows the clutch assembly to be easily moved out and installed, and there is no obstruction in the disassembly and assembly direction when the shaft components move.

[0075] refer to Figure 19 In this embodiment, the intermediate shaft large gear 402 is hydraulically ejected and replaced via the disassembly and assembly hydraulic pressure hole 407 on the gear shaft. The output shaft is similarly replaced by hydraulically ejecting the driven gear 502 via the disassembly and assembly hydraulic pressure hole 407 on the gear shaft. This embodiment separates the intermediate shaft large gear 402 and driven gear 502 from the intermediate shaft and output shaft, removing the shaft and other components first, and then removing the intermediate shaft large gear 402 and driven gear 502, which have a large outer diameter and cannot be directly passed through. This allows for the smooth removal of all components from the gearbox. In this embodiment, the top cover plate 706 is removed from the gearbox body 701, and the intermediate shaft large gear 402 and driven gear 502 are lifted out from above the gearbox.

[0076] refer to Figure 17In this embodiment and some other embodiments, the first clutch assembly 200 includes a first clutch housing, a first clutch seat 205, and an inner friction plate fixed on the first clutch housing and an outer friction plate fixed on the first clutch seat 205. The inner and outer friction plates are alternately arranged. The first clutch housing is integrally formed with the right-hand drive gear 204. The first clutch seat 205 is welded to the drive gear assembly 202. The first clutch seat 205 is connected to the input shaft 201 through a ninth tapered roller bearing 217. The first clutch assembly 200 is located near the output rear cover 704. The second clutch assembly 300 includes a second clutch housing, a second clutch seat, and an inner friction plate fixed on the second clutch housing and an outer friction plate fixed on the second clutch seat. The inner and outer friction plates are alternately arranged. The second clutch housing is integrally formed with the left-hand drive gear 302. The second clutch seat is welded to the drive gear assembly 303. The second clutch seat is connected to the drive shaft 301 through a tenth tapered roller bearing 317. The second clutch assembly 300 is located near the output rear cover 704. In this embodiment, the first clutch seat 205 is fixed to the drive gear assembly 202 by electron beam welding, and the second clutch seat is also fixed to the transmission gear assembly 303 by electron beam welding. This arrangement results in high connection strength between the clutch assembly and the gear assembly, smaller weld seams, and a shorter overall length of the drive gear assembly. Traditional drive gear assemblies require a space between the clutch seat and the gear to facilitate the withdrawal of the milling cutter used for machining the teeth, which makes the drive gear assembly longer. Alternatively, the teeth and clutch seat may be radially misaligned, resulting in a larger radial volume for the drive gear assembly, which is not conducive to the miniaturization of the gearbox. If the teeth and clutch are machined separately and connected by splines, a bearing and housing connection are required between them for support. However, this method would prevent the gear shaft from being moved out. Therefore, this embodiment uses welding to achieve both high connection strength and a shorter length. The shaft is connected to the housing only through bearings at both ends, eliminating the need for a housing connection in the middle for support, allowing the shaft component to be easily withdrawn.

[0077] Specifically, refer to Figure 17In this embodiment, the input shaft 201 on the input shaft assembly 20 is not fixed on the power input side and the input flange. A rubber toothed sleeve coupling or a high-elasticity coupling 10 is connected to the input shaft assembly 20 on the power input side. The high-elasticity coupling 10 is fixedly connected to the coupling 203. The coupling 203 is connected to the input shaft 201 via a spline, allowing the input shaft 201 to be easily removed. The right-hand drive gear 204 is thermally fitted to the input shaft 201. The clutch assembly includes a clutch housing, a clutch seat 205, a piston 206, a spring 207, a spring support plate 208, an outer friction plate 209, an inner friction plate 210, and a pressure plate 211. The outer friction plate 209 and the inner friction plate 210 are respectively connected to the outer spline on the clutch seat and the spline on the clutch housing on the right-hand drive gear 204. The piston 206 is disposed in the inner cavity of the right-hand drive gear 204. The spring support plate 208 is fixed to the input shaft 201. On the 01, the spring 207 is disposed between the piston 206 and the spring support plate 208; the pressure plate 211 is fixed to the clutch seat 205 or the clutch housing at the end away from the piston, and pressure oil is introduced to make the piston 206 move, pressing the outer friction plate 209 and the inner friction plate 210, thereby causing the right-hand drive gear 204 and the driving gear assembly 202 to rotate simultaneously, releasing the pressure oil, and the piston 206 is reset under the action of the spring 207, so that the right-hand drive gear 204 disengages from the driving gear assembly 202. An oil seal is provided between the input shaft 201 and the front end of the housing. In this embodiment, the second clutch assembly 300 in the drive shaft component 30 has the same specific structure as the first clutch assembly 200 in the input shaft component 20. The driven gear 502 is fitted onto the output shaft 501 by heat fitting or tapered fitting, and the other end of the output shaft 501 is provided with an output flange 503, and the output shaft 501 and the output flange 503 are connected by spline or tapered fitting.

[0078] refer to Figure 9 In this embodiment, the housing 70 includes a cover 705 of a high-elastic coupling 10 or a rubber toothed sleeve coupling, a housing 701, a bearing seat plate 702, an integrated rear cover 703, a top cover plate 706 and an output rear cover 704 disposed above the housing 701. The cover 705, bearing seat 702, integrated rear cover 703, top cover plate 706 and output rear cover 704 are connected to the housing 701 by bolts. In this embodiment, the bearing seat plate 702 has an "eight" structure, that is, it is divided into an inner ring and an outer ring that are coaxially integrally formed. The inner ring extends into the first disassembly hole 7011 to provide support for the bearing, and the outer ring abuts against the outside of the housing 701 and is detachably connected to the housing. In this embodiment, the pressure plate in the clutch assembly is provided with an emergency bolt for use as an emergency device, and the bolt is located below the top cover plate 706. An oil seal is provided between the output shaft 501 and the output rear cover 704. The output end of the output shaft 501 is also connected to the output flange 503 through a spline or tapered fitting.

[0079] refer to Figure 10 In this embodiment and some other embodiments, the large-diameter ends of the inner rings of the first tapered roller bearing 215, the second tapered roller bearing 315, the third tapered roller bearing 403, and the fourth tapered roller bearing 504 are oriented towards the first disassembly hole 7011, while the small-diameter ends of the inner rings of the fifth tapered roller bearing 218, the sixth tapered roller bearing 318, the seventh tapered roller bearing 404, and the eighth tapered roller bearing 505 are oriented towards the first disassembly hole 7011. In this embodiment, the large-diameter ends of the inner rings of the ninth and tenth tapered roller bearings are oriented towards the first disassembly hole 7011. The arrangement of the tapered roller bearings allows the shaft to be pulled out entirely by removing the outer rings fixedly connected to the bearing housing plate 702, and provides good axial support for the shaft components in this embodiment, improving disassembly convenience while ensuring sufficient stability of the gearbox.

[0080] In this invention, the gearbox housing 701, bearing seat plate 702, and integrated rear cover 703 are all integral components, and the intermediate shaft component 40 does not have a separate sealing cover. This not only reduces the mating surfaces between the housing and the cover, and between housings, thus reducing the risk of oil leakage, but more importantly, it eliminates the need to hoist heavy parts such as the upper and middle housings. Simply remove the bearing seat and integrated rear cover 703, and pump out the hydraulic pressure through the disassembly and assembly hydraulic hole 407 on the intermediate shaft to replace the output shaft. Similarly, this allows for the replacement of friction plates and high-elasticity components without the cover 705 without moving the main unit and gearbox, or the removal of the cover 705, as well as the extraction of the input shaft component 20, transmission shaft component 30, intermediate shaft component 40, and output shaft component 50.

[0081] This embodiment also provides a method for disassembling a two-stage marine gearbox, applicable to the aforementioned two-stage marine gearbox, comprising the following steps:

[0082] S1: Remove the integrated rear cover 703, the output rear cover 704, and the bearing seat plate 702;

[0083] S2: The input shaft component 20 and the transmission shaft component 30 are pulled out by translation from the first disassembly hole 7011;

[0084] S3: Hydraulically eject the intermediate shaft gear 402 in the intermediate shaft component 40 that is connected to the input shaft component 20 and the transmission shaft component, so that it is separated from the intermediate shaft 401. Move and pull out the other components on the input shaft component 20 except for the intermediate shaft gear 402 from the first disassembly hole 7011, and then remove the intermediate shaft gear 402.

[0085] S4: Hydraulically eject the driven gear 502 in the output shaft assembly 50 that is connected to the intermediate shaft assembly 40, so that it is separated from the output shaft 501. Move and pull out the other components in the output shaft assembly 50 except for the driven gear 502 from the second disassembly hole 7012, and then remove the driven gear 502.

[0086] In this embodiment of the invention, when maintenance of the gearbox is required, all connecting bolts and pins of the housing 701, bearing seat plate 702, and integrated rear cover 703 are unscrewed. Then, the integrated rear cover 703, bearing seat plate 702, and other components are removed. The input shaft component 20, drive shaft component 30, or intermediate shaft component 40 can then be pulled out entirely through the first disassembly hole 7011. This allows for the replacement of components such as the input shaft component 20, drive shaft component 30, and intermediate shaft component 40. Compared to traditional gear structures, maintenance does not require moving the main unit and stern shaft, realigning the gearbox's three alignment lines, or unscrewing the upper, middle, and lower housing assembly bolts, or lifting the upper and middle housings—significantly saving maintenance time and costs. This embodiment features a compact overall structure, small size, light weight, and high reliability.

[0087] Specifically, the component replacement steps for the two-stage transmission marine gearbox in this embodiment are as follows:

[0088] Replace the friction plate: Remove the integrated back cover 703 → Remove the bearing seat plate 702, including the bearing outer ring fixed on the bearing seat plate 702 → Pull out the entire input shaft component 20 or transmission shaft component 30. The bearing inner hole and shaft clearance fit at the left end are matched, so the bearing inner ring is also left in the housing → Replace the friction plate.

[0089] Replace the high-elasticity coupling 10: After the above process of replacing the friction plate → remove the flywheel connecting bolts → move the high-elasticity coupling 10 and the input flange together a certain distance towards the gearbox and then lift them upwards → replace the high-elasticity coupling 10.

[0090] Replace intermediate shaft assembly 40: Remove integrated back cover 703 → Remove bearing seat plate 702 → Pull out the input shaft assembly 20 and transmission shaft assembly 30 as a whole → Use a hydraulic disassembly tool inside the housing to separate the intermediate shaft large gear 402 from the intermediate shaft 401 → Pull out the intermediate shaft 401. The inner hole of the bearing at the left end of the intermediate shaft assembly has a clearance fit with the intermediate shaft, so the intermediate shaft can be pulled out directly → Replace any part on the intermediate shaft assembly 40.

[0091] Replace the output shaft assembly 50: Remove the output flange 503 → Remove the output rear cover 704 → Use a hydraulic disassembly tool inside the housing to separate the driven gear 502 from the output shaft 501 → Pull out the output shaft 501. The inner hole of the bearing at the left end of the output shaft assembly has a clearance fit with the output shaft, so the output shaft can be pulled out directly → Replace any part on the output shaft assembly 50.

[0092] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A two-stage marine gearbox that is easy to disassemble and maintain, comprising a housing (70), an input shaft assembly (20), a transmission shaft assembly (30), an intermediate shaft assembly (40), and an output shaft assembly (50). The input shaft assembly (20) is connected to the transmission shaft assembly (30), and the intermediate shaft assembly (40) is connected to the output shaft assembly (50). The intermediate shaft assembly (40) can be connected to both the input shaft assembly (20) and the transmission shaft assembly (30). The input shaft assembly (20) is provided with a first clutch assembly (200), and the transmission shaft assembly (30) is provided with a second clutch assembly (300). By controlling the engagement and disengagement of the first clutch assembly (200) and the second clutch assembly (300), the intermediate shaft assembly (40) can have different rotation directions. The rotation direction of the intermediate shaft assembly (40) when connected to the input shaft assembly (20) is opposite to that when connected to the transmission shaft assembly (30). On the side near the power input end, the input shaft assembly (20) is connected to the housing (70) via a first tapered roller bearing (215). The outer ring of the first tapered roller bearing (215) is interference-fitted with the housing (70), and the inner ring of the first tapered roller bearing (215) is clearance-fitted with the input shaft assembly (20). The drive shaft assembly (30) is connected to the housing (70) via a second tapered roller bearing (315). The outer ring of the second tapered roller bearing (315) is interference-fitted with the housing (70), and the inner ring of the second tapered roller bearing (315) is clearance-fitted with the input shaft assembly (20). The intermediate shaft component (40) and the housing (70) are connected by a third tapered roller bearing (403). The outer ring of the third tapered roller bearing (403) is interference-fitted with the housing (70), and the inner ring of the third tapered roller bearing (403) is clearance-fitted with the intermediate shaft component (40). The output shaft component (50) and the housing (70) are connected by a fourth tapered roller bearing (504). The outer ring of the fourth tapered roller bearing (504) is interference-fitted with the housing (70), and the inner ring of the fourth tapered roller bearing (504) is clearance-fitted with the output shaft component (50). On the side away from the power input end, the housing (70) includes a housing (701), a bearing seat plate (702), and an output rear cover (704). The housing (701) is provided with a first disassembly hole (7011) and a second disassembly hole (7012). During disassembly and assembly, the input shaft component (20) and the transmission shaft component (30) can be moved out or installed through the first disassembly hole (7011). The intermediate shaft (401) in the intermediate shaft component (40) and the intermediate shaft transmission gear (405) meshing with the output shaft component (50) can be moved out or installed through the first disassembly hole (7011). The output shaft (501) of the output shaft component (50) can be moved out or installed through the second disassembly hole (7012). The bearing seat plate (702) and the output rear cover (704) are also provided with a first disassembly hole (7011) and a second disassembly hole (7012). The rear cover (704) is detachably connected to the housing (701). The input shaft component (20) is connected to the bearing seat plate (702) via the fifth tapered roller bearing (218). The transmission shaft component (30) is connected to the bearing seat plate (702) via the sixth tapered roller bearing (318). The intermediate shaft component (40) is connected to the bearing seat plate (702) via the seventh tapered roller bearing (404). The output shaft component (50) is connected to the output rear cover (704) via the eighth tapered roller bearing (505). An integrated rear cover (703) is detachably connected to the bearing seat plate (702). An integrated oil circuit is integrally formed on the integrated rear cover (703). The main oil pump (90) supplies oil to the input shaft component (20) and the transmission shaft component (30) through the integrated oil circuit.

2. The two-stage transmission marine gearbox as described in claim 1, characterized in that, The integrated rear cover (703) has a first shaft hole (7032) that mates with the outer peripheral shape of the input shaft (201) in the input shaft assembly (20), and a second shaft hole (7033) that mates with the outer peripheral shape of the drive shaft (301) in the drive shaft assembly (30). The inner wall of the first shaft hole (7032) mates with the outer peripheral side of the input shaft (201). An oil inlet for the co-moving working oil passage (130) is provided on the outer peripheral side of the input shaft (201), so that the first shaft hole (7032) The first oil inlet hole on the inner side wall is connected to the forward working oil passage (130) in the input shaft. The inner side wall of the second shaft hole (7033) is matched with the outer peripheral side of the transmission shaft. The outer peripheral side of the transmission shaft (301) is provided with the oil inlet of the reverse working oil passage (120), so that the second oil inlet hole on the inner side wall of the second shaft hole (7033) is connected to the reverse working oil passage (120) in the input shaft (201). The first oil inlet hole and the second oil inlet hole are respectively connected to the working oil port of the main oil pump (90) through the control valve.

3. A two-stage transmission marine gearbox that is easy to disassemble and maintain as described in claim 2, characterized in that, The integrated rear cover (703) includes a cover plate (7035) and a hollow first protrusion (7031). The hollow part of the first protrusion (7031) is a second shaft hole (7033). The end of the first protrusion (7031) is provided with an oil pump inlet hole (70311) and an oil pump outlet hole (70312). The oil pump inlet hole (70311) and the oil pump outlet hole (70312) are connected. The outer side wall of the first protrusion (7031) has an oil pump suction hole (70313) connected to the oil pump (100) and an oil filter (8). 0) The oil filter inlet (70314) is connected to the input end and the oil filter outlet (70315) is connected to the output end of the oil filter (80). The oil suction port (70313) of the suction pump is connected to the oil suction port (70311). The oil suction port (70312) of the suction pump is connected to the oil filter inlet (70314). The oil filter (80) is fixed on the integrated back cover (703). The oil filter outlet (70315) is connected to the main oil pump (90). The oil suction pump (100) is used to pump oil from the bottom of the tank into the oil suction port (70313).

4. A two-stage transmission marine gearbox that is easy to disassemble and maintain as described in claim 2, characterized in that, The integrated rear cover (703) is also provided with a second protrusion (7034) for connecting the control system component (60). The control system component (60) is equipped with a control valve and a control valve controller for controlling the control valve. The control system component (60) and the second protrusion (7034) are detachably connected. The second protrusion (7034) is provided with a main oil pump inlet (70341). The input end of the main oil pump inlet (70341) is connected to the main oil pump (90), and the output end of the main oil pump inlet (70341) is connected to the working oil circuit and the main lubrication oil circuit (110). The second protrusion (7034) is close to the control system component (60). The control valve inlet (70342) is provided on the side and is connected to the main oil pump inlet (70341). The oil enters the control system component (60) from the control valve inlet (70342). The second protrusion (7034) is also provided with a forward working oil hole (70343) and a reverse working oil hole (70344). One end of the forward working oil hole (70343) is connected to the forward output end of the control system component (60), and the other end is connected to the forward working oil circuit (130). One end of the reverse working oil hole (70344) is connected to the reverse output end of the control system component (60), and the other end is connected to the reverse working oil circuit (120).

5. A two-stage transmission marine gearbox that is easy to disassemble and maintain as described in claim 4, characterized in that, The inner wall of the first shaft hole (7032) and the inner wall of the second shaft hole (7033) are connected through the first lubricating oil passage (1101). The first lubricating oil passage (1101) is connected to the main oil pump inlet hole (70341). A cavity is formed between the inner wall of the first shaft hole (7032) and the front end of the input shaft. The front end of the input shaft is provided with an input oil port for the lubricating oil passage inside the input shaft. A cavity is formed between the inner wall of the second shaft hole (7033) and the front end of the transmission shaft. The front end of the transmission shaft is provided with an input oil port for the lubricating oil passage inside the transmission shaft.

6. A two-stage transmission marine gearbox that is easy to disassemble and maintain as described in claim 5, characterized in that, The output ports of the lubrication circuit in the input shaft include an oil distribution port leading to the first tapered roller bearing (215) and the housing (701), an oil distribution port leading to the fifth tapered roller bearing (218) and the integrated back cover (703), and an oil distribution port leading to the inner wall of the inner ring of the first tapered roller bearing (215). The output ports of the lubrication circuit in the transmission shaft include an oil distribution port leading to the second tapered roller bearing (315) and the housing (701), an oil distribution port leading to the sixth tapered roller bearing (318) and the integrated back cover (703), and an oil distribution port leading to the inner wall of the inner ring of the second tapered roller bearing (315).

7. A two-stage transmission marine gearbox that is easy to disassemble and maintain as described in claim 1, characterized in that, The intermediate shaft (401) in the intermediate shaft assembly (40) is connected to the housing (701) via a third tapered roller bearing (403). A first oil sump (406) is provided between the third tapered roller bearing (403) and the housing (701). The intermediate shaft (401) has a drain hole at its end. The side wall of the intermediate shaft (401) is provided with an oil port leading to the inner ring of the third tapered roller bearing (403). The oil port is connected to the drain hole. The central protrusion of the first oil sump (406) leads into the drain hole to concentrate the oil splashed by the third tapered roller bearing (403) into the drain hole. The output shaft (501) in the output shaft assembly (50) is connected to the housing (701) via a fourth tapered roller bearing (504). A second oil sump (506) is provided between the fourth tapered roller bearing (504) and the housing (701). The output shaft (501) has a drain hole at its end. The side wall of the output shaft (501) is provided with an oil port leading to the inner ring of the fourth tapered roller bearing (504). The oil port is connected to the drain hole. The central protrusion of the second oil sump (506) leads into the drain hole to concentrate the oil splashed by the third tapered roller bearing (403) into the drain hole.

8. A two-stage transmission marine gearbox that is easy to disassemble and maintain as described in claim 1, characterized in that, The input shaft component (20) includes an input shaft (201) and a drive gear assembly (202), a first clutch assembly (200), and a right-hand drive gear (204) sequentially arranged on the input shaft. The right-hand drive gear (204) is fixedly connected to the input shaft (201), and the drive gear assembly (202) is connected to the input shaft (201) through a bearing. Both the right-hand drive gear (204) and the drive gear assembly (202) are fixedly connected to the first clutch assembly (200). When the first clutch assembly (200) is engaged, the drive gear assembly (202) can engage with the right-hand drive gear (204) and rotate synchronously. The right-hand drive gear (204) is located near the first disassembly hole (7011). The drive shaft assembly (30) includes a drive shaft (301) and a drive gear assembly (303), a second clutch assembly (300), and a left-hand drive gear (302) sequentially arranged on the drive shaft (301). The left-hand drive gear (302) is fixedly connected to the input shaft (201). The drive gear assembly (303) is connected to the drive shaft (301) through a bearing. Both the left-hand drive gear (302) and the drive gear assembly (303) are fixedly connected to the second clutch assembly (300). When the second clutch assembly (300) is engaged, the drive gear assembly (303) can engage with the left-hand drive gear (302) and rotate synchronously. The left-hand drive gear (302) is located near the first disassembly hole (7011). The intermediate shaft assembly (40) includes an intermediate shaft (401) and an intermediate shaft gear (402) and an intermediate shaft transmission gear (405) fixedly connected to the intermediate shaft (401). The first clutch assembly (200) and the second clutch assembly (300) are located closer to the first disassembly hole (7011) than the intermediate shaft gear (402). The output shaft assembly (50) includes an output shaft (501) and a driven gear (502) fixedly connected to the output shaft (501). The right-hand drive gear (204) meshes with the left-hand drive gear (302) for transmission. The intermediate shaft large gear (402) meshes with the drive gear assembly (202) and the transmission gear assembly (303) for transmission. The intermediate shaft drive gear (405) meshes with the driven gear (502) for transmission.

9. A two-stage transmission marine gearbox that is easy to disassemble and maintain as described in claim 1, characterized in that, The large diameter ends of the inner rings of the first tapered roller bearing (215), the second tapered roller bearing (315), the third tapered roller bearing (403), and the fourth tapered roller bearing (504) are arranged facing the first disassembly hole (7011), while the small diameter ends of the inner rings of the fifth tapered roller bearing (218), the sixth tapered roller bearing (318), the seventh tapered roller bearing (404), and the eighth tapered roller bearing (505) are arranged facing the first disassembly hole (7011).

10. A method for disassembling a two-stage marine gearbox, applicable to a two-stage marine gearbox that is easy to disassemble and maintain as described in any one of claims 1-9, characterized in that... Includes the following steps: S1: Remove the integrated rear cover (703), output rear cover (704), and bearing seat plate (702). S2: The input shaft assembly (20) and the transmission shaft assembly (30) are pulled out by translation from the first disassembly hole (7011). S3: The intermediate shaft gear (402) in the intermediate shaft component (40) that is connected to the input shaft component (20) and the transmission shaft component is hydraulically ejected to separate it from the intermediate shaft (401). Other components on the input shaft component (20) except for the intermediate shaft gear (402) are moved out through the first disassembly hole (7011) and then the intermediate shaft gear (402) is removed. S4: Hydraulically eject the driven gear (502) in the output shaft assembly (50) that is connected to the intermediate shaft assembly (40) to separate it from the output shaft (501). Move and pull out the other components in the output shaft assembly (50) except for the driven gear (502) from the second disassembly hole (7012). Then remove the driven gear (502).

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