A stern shaft sealing arrangement for a marine vessel

Abstract

The application discloses a ship stern shaft sealing device and belongs to the technical field of stern shaft sealing. The device comprises an oil seal cylinder and a main body mechanism for crushing waterweeds and sundries wound on a power stern shaft when the ship is running. An oil seal mechanism for lubricating and sealing the power stern shaft and two sealing mechanisms for sealing the power stern shaft are arranged in the oil seal cylinder. The pressure compensation mechanism composed of a slidable pressure maintaining sliding block and a sliding block spring and an inner contact ring and a contact ring spring is arranged in the oil seal cylinder. When the external oil pump injects oil into the oil seal cylinder, the oil pushes the pressure maintaining sliding block and the inner contact ring to compress the spring, the elastic force of the compressed spring provides continuous and stable back pressure for the oil, the oil pressure in the oil seal cylinder is always higher than the seawater pressure when the ship is sailing, a positive pressure barrier is formed, seawater is prevented from seeping inwards, and the reliability of the sealing device is improved.

Description

Technical Field

[0001] This invention relates to the field of stern shaft sealing technology, and particularly to a ship stern shaft sealing device. Background Technology

[0002] The stern shaft system is a core component of a ship's propulsion system, and its sealing performance directly affects the ship's navigation safety and operational efficiency. Stern shaft seals primarily prevent seawater from entering the hull along the stern shaft and simultaneously lubricate it to reduce friction and wear. However, existing stern shaft seals still have the following shortcomings in practical applications.

[0003] First, during navigation, the stern shaft, located outside the hull, is prone to becoming entangled with seaweed, fishing nets, and other debris. This entanglement not only increases the shaft's rotational resistance, reducing propulsion efficiency, but can also damage the sealing structure, leading to seawater leakage. Traditional solutions typically require the ship to stop or dock for manual cleaning, which is cumbersome and costly, and cannot automatically resolve the debris entanglement problem during navigation.

[0004] Secondly, the lubrication and pressure balancing mechanism of the stern shaft sealing device is not yet perfect. The stern shaft requires continuous oil lubrication to reduce friction during high-speed rotation, and the oil pressure inside the sealing cavity must be higher than the external seawater pressure to effectively prevent seawater infiltration. However, existing devices struggle to detect and compensate for oil leaks or deficiencies in a timely manner, increasing the risk of seal failure. Furthermore, the sealing structure has high friction, which can easily lead to component wear over long-term operation, affecting the device's service life.

[0005] Furthermore, the dynamic sealing performance between the stern shaft and the seals needs improvement. Due to radial runout and axial movement of the stern shaft during operation, traditional seals struggle to maintain a tight seal, easily creating gaps and reducing sealing effectiveness. Simultaneously, the lubrication method of the sealing structure is relatively simple, failing to form a stable oil film between rotating parts, further limiting the reliability and durability of the seal.

[0006] In summary, existing stern shaft sealing devices have shortcomings in terms of debris removal, pressure maintenance, and dynamic sealing, and there is an urgent need to improve the operational safety and maintenance convenience of ships. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention discloses a stern shaft sealing device capable of automatically breaking up tangled debris, maintaining stable oil pressure, and achieving efficient dynamic sealing. The technical solution adopted by this invention is as follows: a ship stern shaft sealing device, comprising an oil seal cylinder and a main body mechanism for breaking up debris such as weeds that entangle on the powered stern shaft during ship movement. The oil seal cylinder is provided with an oil seal mechanism for lubricating and sealing the powered stern shaft and two sealing mechanisms for sealing the powered stern shaft.

[0008] Furthermore, the main structure includes a front cover plate and a rear cover plate fixedly installed at both ends of the oil seal cylinder. Two oil inlets are provided on the side of the oil seal cylinder. The power stern shaft passes through the front cover plate, the oil seal cylinder, and the rear cover plate. Multiple power blades are provided on the power stern shaft. The rear cover plate is fixedly installed with the ship.

[0009] Furthermore, the main structure also includes an outer protective shell fixedly installed on the rear end cover plate. The outer protective shell is located outside the hull. An inner cleaning sleeve is fixedly installed on the power stern shaft. The inner cleaning sleeve is provided with multiple inner crushing teeth. Multiple outer crushing teeth are fixedly installed on the inner side of the outer protective shell. The outer crushing teeth and the inner crushing teeth are arranged alternately. Multiple slag discharge holes are provided on the outer protective shell.

[0010] When the ship is moving, the propulsion is provided by the rotation of the propulsion blades driven by the power stern shaft. Debris such as weeds can easily get tangled on the part of the power stern shaft located outside the hull and on the inner cleaning sleeve. At this time, the weeds are located between the power stern shaft and the outer shell. When the power stern shaft rotates, it drives the inner cleaning sleeve to rotate simultaneously. The inner cleaning sleeve breaks up the tangled weeds through the inner breaking teeth and the outer breaking teeth fixed inside the outer shell. The broken weeds generate centrifugal force under the high-speed rotation of the power stern shaft and the inner cleaning sleeve. Then the broken weeds are thrown out from the slag discharge hole, thus removing the weeds tangled on the power stern shaft outside the hull.

[0011] Furthermore, the oil seal mechanism includes a central groove ring fixedly installed in the middle of the inner wall of the oil seal cylinder. An arc-shaped groove is provided on the inner side of the central groove ring. Multiple annular groove balls are evenly rotatably installed in the arc-shaped groove of the central groove ring. The power stern shaft is located inside all the annular groove balls and is in contact with the annular groove balls. Two oil inlet hoppers are provided on the oil seal cylinder, and oil is filled into the oil seal cylinder.

[0012] Furthermore, the oil seal mechanism also includes multiple sealing sleeves disposed on the inner wall of the oil seal cylinder, a pressure-holding slider is slidably installed inside the sealing sleeve, the sealing sleeve is fixedly installed with the central groove ring, and a slider spring is disposed between the pressure-holding slider and the central groove ring, the slider spring being located in the sealing sleeve.

[0013] Furthermore, the oil seal mechanism also includes two inner fixing sleeves that are fixedly installed at both ends of the oil seal cylinder. The inner fixing sleeves are slidably mounted with inner contact rings, and inner transverse guide posts are fixedly mounted on the inner contact rings. The inner transverse guide posts are slidably mounted with the inner fixing sleeves. A connecting spring is provided between the inner contact rings and the inner fixing sleeves. There is a closed space between the inner fixing sleeves and the inner contact rings. The connecting spring is located in the closed space. An inner sensor is fixedly installed at the end of the inner transverse guide post away from the inner contact ring.

[0014] Before use, insert the external oil inlet pipe into the oil inlet and connect it to the oil hopper. An external oil pump injects oil into the oil seal cylinder through the oil hopper. As oil is continuously injected into the oil seal cylinder, the pressure inside increases. The oil pushes the pressure-holding slider along the groove on the inner wall of the oil seal cylinder towards the central groove ring, compressing the slider spring. Simultaneously, the oil pushes the inner contact ring and inner transverse guide post outward along the oil seal cylinder and inner fixed sleeve, compressing the connecting ring spring. This causes the inner sensor to disengage from the inner fixed sleeve. The compressed slider spring and connecting ring spring provide a certain pressure, ensuring that the oil pressure inside the oil seal cylinder is greater than the pressure below sea level during ship navigation, preventing seawater from seeping into the oil seal cylinder. When the oil level in the oil seal cylinder is insufficient, it cannot maintain the compressed state of the slider spring and connecting ring spring. At this time, the slider spring and connecting ring spring rebound. When the inner sensor contacts the inner fixed sleeve, an alarm is triggered, indicating that the oil level in the oil seal cylinder is insufficient and needs to be replenished promptly.

[0015] When the powered stern shaft rotates, the powered stern shaft inside the oil seal cylinder is lubricated by the oil inside the oil seal cylinder, and the friction force during the rotation of the powered stern shaft is reduced by the annular groove balls.

[0016] Furthermore, the sealing mechanism includes inner fixing sleeves fixedly installed at both ends of the oil seal cylinder, the inner fixing sleeve of the sealing mechanism located next to the front cover plate is fixedly installed with the front cover plate, the inner fixing sleeve of the sealing mechanism located next to the rear cover plate is fixedly installed with the rear cover plate, and two annular grooves are provided on the inner side of the inner fixing sleeve.

[0017] Furthermore, the sealing mechanism also includes a rotating outer shell rotatably installed within the inner fixed sleeve. The rotating outer shell is provided with a ball bearing groove, on which multiple central balls are rotatably installed at equal intervals. The rotating outer shell is also provided with an arc-shaped groove, in which multiple inner balls are rotatably installed at equal intervals. The central balls and inner balls are respectively located in two annular grooves on the inner side of the inner fixed sleeve. An oil inlet gap for oil to enter is provided between the inner fixed sleeve and the inner side of the rotating outer shell. The outer side of the rotating outer shell of the sealing mechanism located next to the front cover plate is in contact with the inner side of the front cover plate. A sealing gasket is provided on the outer side of the front cover plate and on the outer side of the rear cover plate.

[0018] Furthermore, the sealing mechanism also includes a bonding steel coil wound on the power stern shaft. The bonding steel coil is wound more than one turn, and side rolled edges that fit against the power stern shaft are provided on both sides of the bonding steel coil. The bonding steel coil and the side rolled edges are located in the rotating outer shell.

[0019] During assembly, the bonding steel coil is first wound around the outside of the power stern shaft, with more than one turn. Then, the bonding steel coil is tightly pressed onto the power stern shaft using an assembled rotating housing. At the same time, the bonding steel coil is tightly fitted to the power stern shaft. The bonding steel coil has a certain degree of elasticity. By tightly pressing the bonding steel coil against the inside of the rotating housing and the outside of the power stern shaft, as well as setting the side rolled edges, the power stern shaft is sealed.

[0020] After the oil is injected into the oil seal cylinder, it enters the space between the inner fixed sleeve and the rotating outer shell through the oil inlet gap. The front and rear cover plates seal the outer side of the rotating outer shell. The oil seals the space between the rotating outer shell and the inner fixed sleeve. When the power stern shaft rotates, the friction is reduced by the middle ball bearings and the inner ball bearings. At the same time, lubrication is achieved between the inner fixed sleeve and the rotating outer shell, thus achieving sealing and lubrication of the power stern shaft at the inner and outer ends of the oil seal cylinder.

[0021] The beneficial effects of this invention compared with the prior art are: (1) This invention sets an outer protective shell on the rear end cover plate and installs an inner cleaning sleeve with inner crushing teeth on the power stern shaft. With the outer crushing teeth arranged alternately on the inner side of the outer protective shell, when weeds and other debris are wrapped around the outside of the stern shaft, the rotational power of the stern shaft itself drives the inner cleaning sleeve to rotate. The relative movement of the inner and outer crushing teeth automatically cuts and crushes the debris. The crushed debris is thrown out from the slag outlet under the centrifugal force generated by high-speed rotation. Online automatic cleaning of debris outside the stern shaft can be achieved without stopping the machine or manual intervention, effectively avoiding (1) Increased resistance and damage to the sealing structure caused by debris entanglement, improving the navigation safety and continuous operation capability of the ship; (2) The present invention provides a pressure compensation mechanism consisting of a sliding pressure-holding slider and a slider spring, as well as an inner contact ring and a connecting ring spring, by setting a sliding pressure-holding slider and a slider spring in the oil seal cylinder. When the external oil pump injects oil into the oil seal cylinder, the oil pushes the pressure-holding slider and the inner contact ring to compress the spring. The elastic force of the compressed spring provides a continuous and stable back pressure for the oil, ensuring that the oil pressure in the oil seal cylinder is always higher than the seawater pressure when the ship is sailing, forming a positive pressure barrier, preventing seawater from leaking inward, and improving the sealing. The reliability of the device; (3) An internal sensor is installed on the inner contact ring of the present invention. When the oil in the oil seal cylinder is sufficient and the pressure is normal, the oil pressure overcomes the spring force to keep the internal sensor separated from the inner fixed sleeve. When the oil pressure is insufficient due to leakage or consumption, the slider spring and the connecting ring spring rebound, push the internal sensor to contact the inner fixed sleeve and trigger the alarm signal. When the oil is insufficient, the operator is reminded to replenish it in time, so as to avoid the seal failure caused by lack of oil, realize preventive maintenance and reduce the equipment failure rate; (4) The sealing mechanism of the present invention adopts a steel coil wrapped around the power stern shaft. The outer side is pressed together with the assembled rotating outer shell, and the elasticity of the steel coil and the side rolled edge are used to form a tight fit with the stern shaft, achieving a reliable basic seal. At the same time, a central ball bearing and an inner ball bearing are set between the inner fixed sleeve and the rotating outer shell, with an oil inlet gap, so that oil can enter between the rotating parts to form a lubricating film. This reduces the frictional resistance when the stern shaft rotates and establishes a dynamic oil film seal between the rotating parts. Combined with the sealing gaskets on the outside of the front cover plate and the rear cover plate, a multi-layer sealing protection system is formed, which ensures good lubrication and extends the service life of the sealing device and the stern shaft. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0023] Figure 2 This is a schematic diagram of the main structure of the present invention. Figure 1 .

[0024] Figure 3 This is a schematic diagram of the main structure of the present invention. Figure 2 .

[0025] Figure 4 This is a schematic diagram of the oil seal mechanism of the present invention. Figure 1 .

[0026] Figure 5 This is a schematic diagram of the oil seal mechanism of the present invention. Figure 2 .

[0027] Figure 6 This is a schematic diagram of the oil seal mechanism of the present invention. Figure 3 .

[0028] Figure 7 This is a schematic diagram of the sealing mechanism of the present invention. Figure 1 .

[0029] Figure 8 This is a schematic diagram of the sealing mechanism of the present invention. Figure 2 .

[0030] Figure 9 This is a schematic diagram of the sealing mechanism of the present invention. Figure 3 .

[0031] Figure 10 for Figure 8 A schematic diagram of the partial structure at point A in the middle.

[0032] Reference numerals: 101-Oil seal cylinder; 102-Front end cover plate; 103-Rear end cover plate; 104-Power stern shaft; 105-Power blades; 106-Oil inlet; 107-Outer casing; 108-Inner cleaning sleeve; 109-Inner crushing teeth; 110-Outer crushing teeth; 111-Slag discharge hole; 201-Inlet oil hopper; 202-Middle grooved ring; 203-Pressure holding slider; 204-Slider Spring; 205-Ring groove ball; 206-Inner fixed sleeve; 207-Inner transverse guide post; 208-Inner contact ring; 209-Connecting ring spring; 210-Inner sensor; 211-Sealing sleeve; 301-Inner fixed sleeve; 302-Oil inlet gap; 303-Ball groove; 304-Central ball; 305-Inner ball; 306-Rotating housing; 307-Side rolled edge; 308-Fitting steel coil. Detailed Implementation

[0033] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0034] Example: Reference Figures 1-10 A ship stern shaft sealing device includes an oil seal cylinder 101 and a main mechanism for breaking up weeds and other debris that get tangled on the power stern shaft 104 when the ship is moving. The oil seal cylinder 101 is provided with an oil seal mechanism for lubricating and sealing the power stern shaft 104 and two sealing mechanisms for sealing the power stern shaft 104.

[0035] like Figure 2 , Figure 3 As shown, the main structure includes a front cover plate 102 and a rear cover plate 103 fixedly installed at both ends of the oil seal cylinder 101. The oil seal cylinder 101 has two oil inlets 106 on its side. The power stern shaft 104 passes through the front cover plate 102, the oil seal cylinder 101 and the rear cover plate 103. The power stern shaft 104 is provided with multiple power blades 105. The rear cover plate 103 is fixedly installed with the ship.

[0036] like Figure 2 , Figure 3 As shown, the main structure also includes an outer protective shell 107 fixedly installed on the rear end cover plate 103. The outer protective shell 107 is located outside the hull. An inner cleaning sleeve 108 is fixedly installed on the power stern shaft 104. The inner cleaning sleeve 108 is provided with a plurality of inner crushing teeth 109. A plurality of outer crushing teeth 110 are fixedly installed on the inner side of the outer protective shell 107. The outer crushing teeth 110 and the inner crushing teeth 109 are arranged alternately. A plurality of slag discharge holes 111 are provided on the outer protective shell 107.

[0037] When the ship is moving, the power propulsion is provided by the rotation of the power blades 105 driven by the power stern shaft 104. Debris such as aquatic plants can easily get tangled on the part of the power stern shaft 104 located outside the hull and on the inner cleaning sleeve 108. At this time, the aquatic plants are located between the power stern shaft 104 and the outer shell 107. When the power stern shaft 104 rotates, it drives the inner cleaning sleeve 108 to rotate synchronously. The inner cleaning sleeve 108 breaks the tangled aquatic plants through the inner breaking teeth 109 and the outer breaking teeth 110 fixed inside the outer shell 107. The broken aquatic plants generate centrifugal force under the high-speed rotation of the power stern shaft 104 and the inner cleaning sleeve 108. Then the broken aquatic plants are thrown out from the slag discharge hole 111, thus removing the aquatic plants tangled on the power stern shaft 104 outside the hull.

[0038] like Figures 4-6 As shown, the oil seal mechanism includes a central groove ring 202 fixedly installed in the middle of the inner wall of the oil seal cylinder 101. An arc-shaped groove is provided on the inner side of the central groove ring 202. Multiple annular groove balls 205 are evenly rotatably installed in the arc-shaped groove of the central groove ring 202. The power stern shaft 104 is located inside all the annular groove balls 205 and is in contact with the annular groove balls 205. Two oil inlet hoppers 201 are provided on the oil seal cylinder 101, and the oil seal cylinder 101 is filled with oil.

[0039] like Figures 4-6 As shown, the oil seal mechanism also includes a plurality of sealing sleeves 211 disposed on the inner wall of the oil seal cylinder 101. A pressure-holding slider 203 is slidably installed inside the sealing sleeve 211. The sealing sleeve 211 is fixedly installed with the central groove ring 202. A slider spring 204 is disposed between the pressure-holding slider 203 and the central groove ring 202. The slider spring 204 is located in the sealing sleeve 211.

[0040] like Figures 4-6 As shown, the oil seal mechanism also includes two inner fixing sleeves 206 that are fixedly installed at both ends of the oil seal cylinder 101. Inner contact rings 208 are slidably installed on the inner fixing sleeves 206. Inner transverse guide posts 207 are fixedly installed on the inner contact rings 208. The inner transverse guide posts 207 are slidably installed with the inner fixing sleeves 206. A connecting spring 209 is provided between the inner contact rings 208 and the inner fixing sleeves 206. There is a closed space between the inner fixing sleeves 206 and the inner contact rings 208. The connecting spring 209 is located in the closed space. An inner sensor 210 is fixedly installed at the end of the inner transverse guide post 207 away from the inner contact rings 208.

[0041] Before use, insert the external oil inlet pipe into the oil inlet 106 and connect it to the oil inlet 201. An external oil pump injects oil into the oil seal cylinder 101 through the oil inlet 201. As oil is continuously injected into the oil seal cylinder 101, the pressure inside the oil seal cylinder 101 increases. The oil pushes the pressure-holding slider 203 along the groove on the inner wall of the oil seal cylinder 101 towards the central groove ring 202, compressing the slider spring 204. Simultaneously, the oil pushes the inner contact ring 208 and the inner transverse guide post 207 outwards along the oil seal cylinder 101 and the inner fixing sleeve 206, compressing the connecting ring spring 209, causing the inner sensor 210 to contact the inner fixing sleeve 206. When the oil seal is disengaged, the compressed slider spring 204 and the retaining spring 209 provide a certain pressure, making the oil pressure inside the oil seal cylinder 101 greater than the pressure below sea level when the ship is sailing, thus preventing seawater from seeping into the oil seal cylinder 101. When the oil in the oil seal cylinder 101 is insufficient, the oil in the oil seal cylinder 101 is not enough to maintain the compressed state of the slider spring 204 and the retaining spring 209. At this time, the slider spring 204 and the retaining spring 209 rebound. When the inner sensor 210 contacts the inner fixing sleeve 206, an alarm is issued, indicating that the oil in the oil seal cylinder 101 is insufficient and that the oil in the oil seal cylinder 101 needs to be replenished in time.

[0042] When the power stern shaft 104 rotates, the power stern shaft 104 inside the oil seal cylinder 101 is lubricated by the oil inside the oil seal cylinder 101, and the friction force when the power stern shaft 104 rotates is reduced by the annular groove balls 205.

[0043] like Figures 7-10 As shown, the sealing mechanism includes inner fixing sleeves 301 fixedly installed at both ends of the oil seal cylinder 101. The inner fixing sleeve 301 of the sealing mechanism located next to the front cover plate 102 is fixedly installed with the front cover plate 102. The inner fixing sleeve 301 of the sealing mechanism located next to the rear cover plate 103 is fixedly installed with the rear cover plate 103. Two annular grooves are provided on the inner side of the inner fixing sleeve 301.

[0044] like Figures 7-10As shown, the sealing mechanism also includes a rotating outer shell 306 rotatably installed inside the inner fixed sleeve 301. The rotating outer shell 306 is provided with a ball groove 303, and multiple central balls 304 are rotatably installed at equal intervals on the ball groove 303. The rotating outer shell 306 is provided with an arc groove, and multiple inner balls 305 are rotatably installed at equal intervals in the arc groove. The central balls 304 and the inner balls 305 are respectively located in two annular grooves on the inner side of the inner fixed sleeve 301. An oil inlet gap 302 for oil to enter is provided between the inner fixed sleeve 301 and the inner side of the rotating outer shell 306. The outer side of the rotating outer shell 306 of the sealing mechanism located next to the front cover plate 102 is in contact with the inner side of the inner fixed sleeve 301. A sealing gasket is provided on the outer side of the front cover plate 102 and on the outer side of the rear cover plate 103.

[0045] like Figures 7-10 As shown, the sealing mechanism also includes a bonding steel coil 308 wound on the power stern shaft 104. The bonding steel coil 308 is wound more than one turn. Side rolled edges 307 that are in contact with the power stern shaft 104 are provided on both sides of the bonding steel coil 308. The bonding steel coil 308 and the side rolled edges 307 are located in the rotating housing 306.

[0046] During assembly, the bonding steel coil 308 is first wound around the outside of the power stern shaft 104, with the bonding steel coil 308 wound more than one turn. Then, the assembled rotating housing 306 is used to tightly press the bonding steel coil 308 onto the power stern shaft 104. At the same time, the bonding steel coil 308 is tightly fitted to the power stern shaft 104. The bonding steel coil 308 has a certain degree of elasticity. By pressing the bonding steel coil 308 tightly against the inside of the rotating housing 306 and the outside of the power stern shaft 104, and by setting the side rolled edge 307, the power stern shaft 104 is sealed.

[0047] When oil is injected into the oil seal cylinder 101, the oil enters between the inner fixed sleeve 301 and the rotating outer shell 306 through the oil inlet gap 302. The front cover plate 102 and the rear cover plate 103 seal the outside of the rotating outer shell 306. The oil seals the space between the rotating outer shell 306 and the inner fixed sleeve 301. When the power stern shaft 104 rotates, the friction is reduced by the middle ball bearing 304 and the inner ball bearing 305. At the same time, lubrication is achieved between the inner fixed sleeve 301 and the rotating outer shell 306, thus achieving sealing and lubrication of the power stern shaft 104 at the inner and outer ends of the oil seal cylinder 101.

[0048] Working principle: During assembly, the bonding steel coil 308 is first wound around the outside of the power stern shaft 104, with the bonding steel coil 308 wound more than one turn. Then, the assembled rotating housing 306 tightly presses the bonding steel coil 308 onto the power stern shaft 104. At the same time, the bonding steel coil 308 is tightly fitted to the power stern shaft 104. The bonding steel coil 308 has a certain degree of elasticity. By pressing the bonding steel coil 308 tightly against the inside of the rotating housing 306 and the outside of the power stern shaft 104, and by setting the side rolled edge 307, the power stern shaft 104 is sealed.

[0049] Before use, insert the external oil inlet pipe into the oil inlet 106 and connect it to the oil inlet 201. An external oil pump injects oil into the oil seal cylinder 101 through the oil inlet 201. As oil is continuously injected into the oil seal cylinder 101, the pressure inside the oil seal cylinder 101 increases. The oil pushes the pressure-holding slider 203 along the groove on the inner wall of the oil seal cylinder 101 towards the central groove ring 202, compressing the slider spring 204. Simultaneously, the oil pushes the inner contact ring 208 and the inner transverse guide post 207 outwards along the oil seal cylinder 101 and the inner fixing sleeve 206, compressing the connecting ring spring 209. This causes the inner sensor 210 to disengage from the inner fixing sleeve 206. A certain pressure is provided by the compressed slider spring 204 and connecting ring spring 209. This ensures that the pressure of the oil inside the oil seal cylinder 101 is greater than the pressure below sea level when the ship is sailing, preventing seawater from seeping into the oil seal cylinder 101. After the oil is injected into the oil seal cylinder 101, the oil enters between the inner fixed sleeve 301 and the rotating outer shell 306 through the oil inlet gap 302. The front cover plate 102 and the rear cover plate 103 seal the outside of the rotating outer shell 306. The oil seals the space between the rotating outer shell 306 and the inner fixed sleeve 301. When the power stern shaft 104 rotates, the friction is reduced by the middle ball bearing 304 and the inner ball bearing 305. At the same time, lubrication is achieved between the inner fixed sleeve 301 and the rotating outer shell 306, thus achieving sealing and lubrication of the power stern shaft 104 at the inner and outer ends of the oil seal cylinder 101.

[0050] When the oil in the oil seal cylinder 101 is insufficient, the oil in the oil seal cylinder 101 is not enough to maintain the compressed state of the slider spring 204 and the connecting spring 209. At this time, the slider spring 204 and the connecting spring 209 rebound. When the inner sensor 210 contacts the inner fixed sleeve 206, an alarm is issued, indicating that the oil in the oil seal cylinder 101 is insufficient and that the oil in the oil seal cylinder 101 needs to be replenished in time.

[0051] When the ship is moving, the power propulsion is provided by the rotation of the power blades 105 driven by the power stern shaft 104. Debris such as aquatic plants can easily get tangled on the part of the power stern shaft 104 located outside the hull and on the inner cleaning sleeve 108. At this time, the aquatic plants are located between the power stern shaft 104 and the outer shell 107. When the power stern shaft 104 rotates, it drives the inner cleaning sleeve 108 to rotate synchronously. The inner cleaning sleeve 108 breaks the tangled aquatic plants through the inner breaking teeth 109 and the outer breaking teeth 110 fixed inside the outer shell 107. The broken aquatic plants generate centrifugal force under the high-speed rotation of the power stern shaft 104 and the inner cleaning sleeve 108. Then the broken aquatic plants are thrown out from the slag discharge hole 111, thus removing the aquatic plants tangled on the power stern shaft 104 outside the hull. When the power stern shaft 104 rotates, the power stern shaft 104 inside the oil seal cylinder 101 is lubricated by the oil inside the oil seal cylinder 101, and the friction force when the power stern shaft 104 rotates is reduced by the annular groove balls 205.

[0052] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the scope of the present invention based on the technical solution and inventive concept of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A ship stern shaft sealing device, comprising an oil seal cylinder, a powered stern shaft mounted on the oil seal cylinder, and a main mechanism for breaking up debris entangled on the powered stern shaft, characterized in that: The oil seal cylinder is equipped with an oil seal mechanism for lubricating and sealing the power stern shaft and two sealing mechanisms for sealing the power stern shaft. The main structure includes a front cover plate and a rear cover plate fixedly installed at both ends of the oil seal cylinder; The main structure also includes an outer protective shell fixedly installed on the rear end cover plate. The outer protective shell is located outside the hull. An inner cleaning sleeve is fixedly installed on the power stern shaft. The inner cleaning sleeve is provided with multiple inner crushing teeth. Multiple outer crushing teeth are fixedly installed on the inner side of the outer protective shell. Multiple slag discharge holes are provided on the outer protective shell. The oil seal mechanism includes a central grooved ring that is fixedly installed in the middle of the inner wall of the oil seal cylinder; The oil seal mechanism further includes a plurality of sealing sleeves disposed on the inner wall of the oil seal cylinder. A pressure-holding slider is slidably installed inside the sealing sleeve. The sealing sleeve is fixedly installed with the central groove ring. A slider spring is disposed between the pressure-holding slider and the central groove ring. The slider spring is located in the sealing sleeve. The oil seal mechanism further includes two inner fixing sleeves that are fixedly installed at both ends of the oil seal cylinder. The inner fixing sleeves are slidably mounted with inner contact rings. The inner contact rings are fixedly mounted with inner horizontal guide posts. The inner horizontal guide posts are slidably mounted with the inner fixing sleeves. A connecting ring spring is provided between the inner contact rings and the inner fixing sleeves. The space between the inner fixing sleeves and the inner contact rings is a closed space. The connecting ring spring is located in the closed space. An inner sensor is fixedly installed at the end of the inner horizontal guide post away from the inner contact ring. The sealing mechanism includes inner fixing sleeves respectively installed at both ends of the oil seal cylinder. One inner fixing sleeve is fixedly installed with the front end cover plate, and the other inner fixing sleeve is fixedly installed with the rear end cover plate. Two annular grooves are provided on the inner side of the inner fixing sleeve. The sealing mechanism further includes a rotating outer shell rotatably installed within the inner fixed sleeve. The rotating outer shell is provided with a ball bearing groove, on which a plurality of central balls are rotatably installed. The rotating outer shell is provided with an arc-shaped groove, in which a plurality of inner balls are rotatably installed. The central balls and the inner balls are respectively located in two annular grooves on the inner side of the inner fixed sleeve. An oil inlet gap for oil to enter is provided between the inner fixed sleeve and the inner side of the rotating outer shell.

2. The ship stern shaft sealing device according to claim 1, characterized in that: The oil seal cylinder has two oil inlets on its side. The power stern shaft passes through the front cover plate, the oil seal cylinder, and the rear cover plate. The rear cover plate is fixedly installed with the ship.

3. A ship stern shaft sealing device according to claim 2, characterized in that: An arc-shaped groove is provided on the inner side of the central groove ring. Multiple annular groove balls are rotatably installed in the arc-shaped groove of the central groove ring. The power stern shaft is located inside all the annular groove balls and is in contact with the annular groove balls. Two oil inlet hoppers are provided on the oil seal cylinder. The two oil inlet hoppers are located on both sides of the central groove ring and are respectively connected to the two oil inlets.

4. A ship stern shaft sealing device according to claim 1, characterized in that: The outer side of the rotating outer shell located next to the front cover plate is in contact with the inner side of the front cover plate, and the outer side of the rotating outer shell located next to the rear cover plate is in contact with the inner side of the rear cover plate.

5. A ship stern shaft sealing device according to claim 4, characterized in that: The sealing mechanism further includes a bonding steel coil wound on the power stern shaft, and the bonding steel coil has side rolled edges on both sides that fit against the power stern shaft. The bonding steel coil and the side rolled edges are located in the rotating outer shell.

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