Tail shaft seal structure for underwater running

Abstract

This utility model discloses a stern shaft sealing structure for underwater submersion, including a stern shaft rotatably supported within a stern tube. An external sealing device is provided at the extended end of the stern tube, comprising a sealing sleeve fixedly connected to the stern shaft and a stern shaft sealing seat mounted on the stern tube. An oil sealing ring and a lip-type water sealing ring are respectively installed on the inner and outer sides of the stern shaft sealing seat. A sealing ring support ring is movably disposed inside the water sealing ring, with one side of the support ring fitting against the back side of the water sealing ring and the other side connected to a support ring piston. The support ring piston is sealed within an annular piston cavity on the stern shaft sealing seat, and the inner cavity of the annular piston cavity communicates with the outside of the stern shaft sealing seat. The underwater stern shaft sealing structure of this utility model can support the elastic sealing body of the stern shaft lip-type sealing ring to prevent the sealing lip from overturning and deforming during deep diving. Furthermore, the strength of its supporting effect varies with the diving depth, maintaining a good sealing effect.

Description

Technical Field

[0001] This utility model relates to a marine accessory, and more particularly to a stern shaft sealing device for an underwater vehicle. Background Technology

[0002] Underwater vehicles typically operate submerged, driven by a propeller mounted on the outer end of the stern shaft. The stern shaft is rotatably supported by bearings within a stern tube that is sealed and fixed to the vehicle's hull. The bearings require lubrication, and the outer end of the bearing needs a good seal to prevent water ingress and ensure normal operation. This seal is typically achieved using a lip seal. Because the underwater vehicle's diving depth varies as needed, the pressure on the outer side of the lip seal changes accordingly. Meanwhile, the pressure on the inner side reflects the internal pressure of the underwater vehicle, maintained at approximately one atmosphere. Therefore, the pressure difference across the stern shaft seal varies with diving depth. When the diving depth is too great, the pressure difference across the seal will exceed the range allowed for normal operation. Lip seals are unbalanced designs, mainly consisting of an elastic sealing body and its inner ring sealing lip. They rely on elasticity to make the lip of the sealing lip contact the shaft surface to form a seal. When the pressure difference on both sides exceeds the range allowed under normal working conditions and is also in a state of change, it is very detrimental to maintaining the sealing performance of the lip seal. It will cause the elastic sealing lip to flip and deform, which will aggravate wear until the seal fails. Utility Model Content

[0003] In view of the above-mentioned shortcomings of the existing technology, the technical problem to be solved by this utility model is to provide a stern shaft sealing structure for underwater submersion, which can support the elastic sealing body of the stern shaft lip seal to prevent the sealing lip from turning over and deforming during deep diving, and the strength of its supporting effect changes accordingly with the diving depth to maintain a good sealing effect.

[0004] To solve the above-mentioned technical problems, this utility model provides a stern shaft sealing structure for underwater submersion, including a stern shaft rotatably supported in a stern tube, an inner end sealing ring at the inner end of the stern tube, and an outer end sealing device at the outer end of the stern tube. The outer end sealing device includes a sealing sleeve fixedly connected to the stern shaft and a stern shaft sealing seat installed on the stern tube. An oil sealing ring is installed on the inner side of the stern shaft sealing seat, and a water sealing ring is installed on the outer side of the stern shaft sealing seat. The water sealing ring is a lip sealing ring. A sealing ring support ring is movably arranged on the inner side of the water sealing ring. The sealing ring support ring is located in the annular cavity between the water sealing ring and the oil sealing ring. One side of the sealing ring support ring is in contact with the back side of the water sealing ring, and the other side of the sealing ring support ring is connected to a support ring piston. The support ring piston is sealed and installed in the annular piston cavity on the stern shaft sealing seat. The inner cavity of the annular piston cavity is connected to the outside of the stern shaft sealing seat.

[0005] In the above structure, an external sealing device is provided at the extended end of the stern tube. This external sealing device includes a sealing sleeve fixedly connected to the stern shaft and a stern shaft sealing seat installed on the stern tube. An oil sealing ring is installed inside the stern shaft sealing seat, and a water sealing ring (a lip seal) is installed outside the stern shaft sealing seat. A sealing ring support ring is movably disposed inside the water sealing ring, located in the annular cavity between the water sealing ring and the oil sealing ring. One side of the sealing ring support ring is in contact with the back side of the water sealing ring. Thus, the sealing of the underwater vehicle's stern shaft is achieved through the external sealing device. The inner oil seal ring is used to prevent the leakage of lubricating oil from the stern shaft support bearing, while the outer water seal ring is used to prevent the entry of water from outside the underwater vehicle. The sealing ring support ring can fit and support the back side of the elastic sealing body of the lip water seal ring. After the elastic sealing body of the lip water seal ring is supported, the pressure difference between the inner and outer sides when water acts on the outer side of the elastic sealing body can be reduced, thereby reducing the possibility of elastic deformation of the elastic sealing body under water pressure. The sealing lip part of the inner ring of the elastic sealing body can also maintain its normal working position, thereby avoiding the overturning and deformation of the sealing lip.

[0006] Furthermore, since the other side of the sealing ring support ring is connected to the support ring piston, and the support ring piston is sealed and installed in the annular piston cavity on the stern shaft seal seat, with the inner cavity of the annular piston cavity communicating with the outside of the stern shaft seal seat, the sealing ring support ring is axially movable relative to the stern shaft. Its supporting force on the back side of the water seal ring's elastic sealing body is provided by the support ring piston. The inner cavity of the annular piston cavity, where the support ring piston communicates with the outside of the stern shaft seal seat, is filled with water at the depth where the underwater vehicle is located. The pressure of this water is the same as the pressure of the water outside the water seal ring due to the same water depth. This pressure acts on the support ring piston, pushing the elastic seal ring support ring against the water seal ring's elastic sealing body. The back side of the sealing body (i.e., the inner side of the water seal ring) is in contact with the water seal ring. Due to the frictional resistance between the outer circumference of the support ring piston and the corresponding annular piston cavity sidewall, the supporting thrust generated by the sealing ring support ring on the back side of the elastic sealing body will be less than the water depth pressure at that location, and thus less than the water depth pressure on the outside of the water seal ring. Regardless of how the underwater vehicle's diving depth changes, the supporting thrust on the back side of the elastic sealing body of the water seal ring is always slightly less than the water depth pressure on the outside of the elastic sealing body. In this way, the pressure difference on both sides of the water seal ring is always maintained within a certain range. This pressure difference is within the range allowed by the normal working state of the lip seal ring, thus maintaining the good sealing effect of the water seal ring.

[0007] In a preferred embodiment of this invention, the stern shaft sealing seat is composed of several seat segments connected axially in a sealing manner. The water sealing ring and oil sealing ring are respectively installed in the corresponding seat segments, and the annular piston cavity is disposed in the corresponding seat segment. This embodiment facilitates the installation of the water sealing ring and oil sealing ring, as well as the arrangement of the annular piston cavity, and also facilitates the installation of the sealing ring support ring and its support ring piston.

[0008] In another preferred embodiment of this invention, the water seal ring is a lip seal ring with a reinforcing skeleton and a self-tightening helical spring, and the opening of the lip seal ring faces outward. With this embodiment, the water seal ring itself can improve rigidity through the reinforcing skeleton to adapt to the high water pressure conditions of deep-sea navigation, and the self-tightening helical spring strengthens the contact force between the sealing lip and the stern shaft sealing sleeve, while the outward-facing opening better prevents water from entering.

[0009] In another preferred embodiment of this invention, the inner cavity of the annular piston chamber is connected to the outside of the stern shaft seal seat through a connecting hole, and a filter is installed at the opening of the connecting hole on the stern shaft seal ring. This embodiment prevents impurities in the water from entering the annular piston chamber, ensuring the normal operation of the support ring piston.

[0010] In a further preferred embodiment of this invention, a drain port is provided at the bottom of the seat section having an annular piston chamber. This drain port communicates with the interior contents of the cabin through a drain communication hole passing through the stern tube. With this embodiment, the drain port can promptly discharge water or oil leaking from the water seal or oil seal, and the amount of water or oil leaked from the interior contents can be used to promptly observe changes in the working state of the water seal or oil seal.

[0011] In another preferred embodiment of this invention, both the inner and outer circumferential surfaces of the support ring piston are connected to the cavity wall of the corresponding annular piston chamber via two piston sealing rings. This embodiment effectively prevents potential leakage between the support ring piston and the cavity wall of the corresponding annular piston chamber.

[0012] In another preferred embodiment of this invention, the piston seal is an O-ring with a rectangular cross-section. Using this embodiment, the rectangular O-ring provides better leak-proof performance in this location compared to a circular O-ring.

[0013] In a further preferred embodiment of this invention, the inner end sealing ring is a rotary plug seal composed of a U-shaped sealing jacket and a V-shaped corrosion-resistant metal spring. This embodiment effectively prevents lubricating oil in the stern tube from leaking through the inner and outer circumferences of the sealing ring. Attached Figure Description

[0014] The underwater stern shaft sealing structure of this utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] Figure 1 This is a schematic diagram of a specific embodiment of the underwater stern shaft sealing structure of this utility model;

[0016] Figure 2 yes Figure 1 A magnified view of the outer end sealing device in the structure shown.

[0017] In the diagram: 1-Stern shaft, 2-Sealing sleeve, 3-Water sealing ring, 4-Outer end sealing device, 5-Sealing ring support ring, 6-Filter, 7-Stern shaft sealing seat, 71-Seat section, 8-Support ring piston, 9-Annular piston cavity, 10-Oil sealing ring, 11-Drain port, 12-Drain connecting hole, 13-Stern tube, 14-Inner end sealing ring, 15-Connecting hole, 16-Piston sealing ring. Detailed Implementation

[0018] exist Figure 1In the underwater submersible stern shaft sealing structure shown, the stern shaft 1 is rotatably supported within the stern tube 13 by two bearings at the front and rear. The stern tube 13 is fixed to the hull of the underwater vehicle. An inner end sealing ring 14 is provided at the inner end of the stern tube 13 to prevent the lubricating oil of the stern shaft bearing from leaking into the interior of the vehicle. The inner end sealing ring 14 is preferably a rotary plug seal composed of a U-shaped sealing sleeve and a V-shaped corrosion-resistant metal spring. An outer end sealing device 4 is provided at the extended end of the stern tube 13. The outer end sealing device 4 is sleeved on the stern shaft 1. The outermost end of the stern shaft 1 is the mounting position of the underwater vehicle's spiral ceramic plate. The outer sealing device 4 includes a sealing sleeve 2 fixed to the stern shaft 1 by a sealing ring and a set screw, and a stern shaft sealing seat 7 installed on the stern tube 13. An oil sealing ring 10 is installed between the inner side of the stern shaft sealing seat 7 and the sealing sleeve 2 to prevent the lubricating oil of the stern shaft bearing from leaking outward. The oil sealing ring 10 can be a lip seal or have the same structure as the inner sealing ring 14. A water sealing ring 3 is installed between the outer side of the stern shaft sealing seat 7 and the sealing sleeve 2. The water sealing ring 3 is a lip seal, preferably a lip seal with a reinforcing skeleton and a self-tightening helical spring. The opening of the lip seal faces outward to prevent water from outside the underwater vehicle from entering the stern tube 13. A sealing ring support ring 5 is movably arranged inside the water sealing ring 3. The sealing ring support ring 5 is located in the annular cavity between the water sealing ring 3 and the oil sealing ring 10. The surface shape of one side of ring 5 is the same as and fits the back surface of the elastic sealing body on water seal ring 3. The innermost edge of this side that fits the back of water seal ring 3 is close to the outer circumferential surface of sealing sleeve 2, so as to minimize the possibility of the sealing lip of water seal ring 3 flipping or deforming under the action of deep diving pressure. The other side of sealing ring support ring 5 is connected to the outer end face of support ring piston 8. Support ring piston 8 is sealed in the annular piston cavity 9 on stern shaft sealing seat 7. The inner cavity of the annular piston cavity 9 where the inner end face of support ring piston 8 is located is connected to the water outside stern shaft sealing seat 7. The water depth pressure of the external water acts on the inner end face of support ring piston 8 to generate a thrust toward water seal ring 3, ensuring that the outer surface of sealing ring support ring 5 and the back surface of elastic sealing body on water seal ring 3 are always in contact.

[0019] See Figure 2The stern shaft seal 7 is composed of several seat sections 71 connected axially in a sealing manner. The seat section 71 shown in the figure consists of three sections. Water sealing rings 3 and oil sealing rings 10 are respectively installed in the corresponding outer and inner seat sections 71. An annular piston chamber 9 is located in the corresponding middle seat section 71. The inner cavity of the annular piston chamber 9 is connected to the external water body of the stern shaft seal 7 through a connecting hole 15 that radially passes through the middle seat section 71. A filter 6 is installed at the opening of the connecting hole 15 on the stern shaft seal 7. The filter 6 is screwed into the opening of the connecting hole 15; a simple screen filter can be used. A drain port 11 is provided at the bottom of the middle seat section 71 where the annular piston chamber 9 is located. This drain port 11 is connected to the internal contents of the cabin through a drain connecting hole 12 that passes through the stern tube 13. The inner and outer circumferential surfaces of the support ring piston 8 are both connected to the cavity wall of the corresponding annular piston cavity 9 through two piston seals 16. The piston seals 16 are O-rings with a rectangular cross-section.

[0020] The above are only some preferred embodiments of this utility model, but this utility model is not limited thereto, and many improvements and modifications can be made. Any improvements and modifications made based on the basic principles of this utility model should be considered to fall within the protection scope of this utility model.

Claims

1. A stern shaft sealing structure for underwater submersion, comprising a stern shaft (1) rotatably supported within a stern tube (13), and an inner end sealing ring (14) provided at the inner end of the stern tube (13), characterized in that: An external sealing device (4) is provided at the extended end of the stern tube (13). The external sealing device (4) includes a sealing sleeve (2) fixedly connected to the stern shaft (1) and a stern shaft sealing seat (7) installed on the stern tube (13). An oil sealing ring (10) is installed on the inner side of the stern shaft sealing seat (7), and a water sealing ring (3) is installed on the outer side of the stern shaft sealing seat (7). The water sealing ring (3) is a lip sealing ring, and a movable part is provided on the inner side of the water sealing ring (3). The sealing ring support ring (5) is located in the annular cavity between the water sealing ring (3) and the oil sealing ring (10). One side of the sealing ring support ring (5) is in contact with the back side of the water sealing ring (3), and the other side of the sealing ring support ring (5) is connected to the support ring piston (8). The support ring piston (8) is sealed in the annular piston cavity (9) on the stern shaft sealing seat (7). The inner cavity of the annular piston cavity (9) is connected to the outside of the stern shaft sealing seat (7).

2. The underwater submersible stern shaft sealing structure according to claim 1, characterized in that: The stern shaft seal seat (7) is composed of several seat sections (71) that are connected in an axial seal. The water seal ring (3) and the oil seal ring (10) are respectively installed in the corresponding seat section (71), and the annular piston cavity (9) is set in the corresponding seat section (71).

3. The underwater submersible stern shaft sealing structure according to claim 1, characterized in that: The water seal ring (3) is a lip seal ring with a reinforcing skeleton and a self-tightening helical spring, and the opening of the lip seal ring faces outward.

4. The underwater stern shaft sealing structure according to claim 1, characterized in that: The inner cavity of the annular piston cavity (9) is connected to the outside of the stern shaft seal (7) through the connecting hole (15). A filter (6) is installed at the opening of the connecting hole (15) on the stern shaft seal (7).

5. The underwater stern shaft sealing structure according to claim 2, characterized in that: A drain port (11) is provided at the bottom of the seat section (71) which has an annular piston chamber (9). The drain port (11) is connected to the contents of the cabin through a drain communication hole (12) passing through the stern tube (13).

6. The underwater submersible stern shaft sealing structure according to claim 1, characterized in that: The inner and outer circumferential surfaces of the support ring piston (8) are connected to the cavity wall of the corresponding annular piston cavity (9) through two piston sealing rings (16).

7. The underwater submersible stern shaft sealing structure according to claim 6, characterized in that: The piston seal (16) is an O-ring with a rectangular cross-section.

8. The underwater submersible stern shaft sealing structure according to claim 1, characterized in that: The inner end sealing ring (14) is a rotary plug seal composed of a U-shaped sealing jacket and a V-shaped corrosion-resistant metal spring.

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