A stern shaft sealing arrangement

Abstract

This invention relates to the field of marine propulsion shaft sealing technology, and discloses a stern shaft sealing device, including a stern shaft sealing ring and a bushing. The bushing has a sealing cavity. The stern shaft sealing ring includes a main body, a first sealing lip, a second sealing lip, a third sealing lip, and a connecting part. The first sealing lip and the second sealing lip are connected to the front and rear sides of the main body, and the third sealing lip and the connecting part are connected to the inner and outer sides of the main body. The first sealing lip contacts and seals the rear wall of the sealing cavity, and the lip of the first sealing lip faces outward. The second sealing lip contacts and seals the front wall of the sealing cavity, and the lip of the second sealing lip faces the lubricating oil cavity inside the stern tube. The third sealing lip contacts and seals the bottom wall of the sealing cavity, and the lip of the third sealing lip faces the side of the first sealing lip. This invention can replace multiple existing sealing rings with one stern shaft sealing ring, thereby reducing the length of the sealing structure, reducing stress concentration at the rear end of the stern shaft bearing in the stern tube, improving wear at the end of the stern shaft bearing, and reducing costs.

Description

Technical Field

[0001] This invention relates to the field of marine propulsion shaft sealing technology, and in particular to a stern shaft sealing device. Background Technology

[0002] Currently, there are generally three types of stern shaft seals for ship propulsion shafting when they extend out of the hull:

[0003] 1. Packing seal: The principle is to insert packing into the stuffing box and then press it with a gland to generate a clamping force on the shaft, thereby achieving a seal; however, this type of seal causes high frictional loss in the shaft system, is prone to heat generation, and wears the shaft journal.

[0004] 2. Simplex cup seal: The simplex cup is a specially structured rubber seal ring with a cross-sectional shape resembling a "J". When used in shaft sealing devices, 3 to 4 J-shaped seal rings are typically used. Figure 1 As shown, the seal is achieved by using the water pressure outside the ship and the oil pressure in the stern tube to generate a certain radial force; however, the stern shaft sealing device of this type of seal is relatively long, and the propeller position is far from the aft bearing of the stern tube, which aggravates the cantilever beam effect of the propeller on the stern shaft, causes stress concentration at the end of the shaft bearing, and aggravates the wear of the end of the white alloy bearing of the stern shaft.

[0005] 3. End-face sealing, also known as axial mechanical sealing, consists of a static friction disc, a dynamic friction disc, and components such as a rubber sleeve or a telescopic spring. Its principle is as follows: the static friction disc is fixed to the stern tube and can only move axially. The pressure exerted by the static friction disc on the dynamic friction disc is ensured by the rubber sleeve or telescopic spring. The dynamic friction disc is connected to the propeller or stern shaft. The axial force of the rubber sleeve or telescopic spring ensures close contact between the two cross-sections of the dynamic and static friction discs, thus achieving a seal. However, this type of stern shaft sealing device has a complex structure and requires high manufacturing and installation standards, and its application in civilian ships has decreased in recent years. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a stern shaft sealing device that effectively shortens the length of the sealing structure, reduces stress concentration at the rear end of the stern shaft bearing, reduces costs, and provides a good sealing effect.

[0007] To solve the above-mentioned technical problems, the present invention provides a stern shaft sealing device, including a stern shaft sealing ring and a bushing surrounding the stern shaft. The bushing has a sealing cavity that seals with the stern shaft sealing ring. The stern shaft sealing ring includes a main body, a first sealing lip, a second sealing lip, a third sealing lip, and a connecting portion connected to the stern shaft tube. The first sealing lip and the second sealing lip are respectively connected to the front and rear sides of the main body. The third sealing lip and the connecting portion are respectively connected to the inner and outer sides of the main body. The first sealing lip makes radial contact with the rear wall of the sealing cavity and the lip opening of the first sealing lip faces outward. The second sealing lip makes radial contact with the front wall of the sealing cavity and the lip opening of the second sealing lip faces the lubricating oil cavity inside the stern shaft tube. The third sealing lip makes axial contact with the bottom wall of the sealing cavity and the lip opening of the third sealing lip faces the side of the first sealing lip.

[0008] As a preferred embodiment of the present invention, the first sealing lip, the second sealing lip, and the third sealing lip are all pre-compressed and installed in the sealing cavity.

[0009] As a preferred embodiment of the present invention, the stern shaft seal is an integrally formed rubber stern shaft seal, and the first sealing lip, the second sealing lip and the third sealing lip are all hook-shaped.

[0010] As a preferred embodiment of the present invention, the main body is quadrilateral, and the first sealing lip, the second sealing lip, the third sealing lip and the connecting portion are respectively connected to the four corners of the main body.

[0011] As a preferred embodiment of the present invention, the connecting part is connected to the stern tube via a stern tube connector. The stern tube connector includes a first connecting ring, a second connecting ring, and a fixing bolt. The connecting part is sandwiched between the first connecting ring and the second connecting ring. The fixing bolt passes through the first connecting ring and the second connecting ring in sequence and is connected to the end of the stern tube.

[0012] As a preferred embodiment of the present invention, the connecting part is provided with locking protrusions on both the front and rear sides, and the first connecting ring piece and the second connecting ring piece are provided with locking grooves that engage with the locking protrusions.

[0013] As a preferred embodiment of the present invention, a sealing gasket is provided between the second connecting ring and the end face of the stern tube.

[0014] As a preferred embodiment of the present invention, the second connecting ring is provided with a baffle extending into the inner wall of the stern tube.

[0015] As a preferred embodiment of the present invention, the bushing includes a first fixing ring, a second fixing ring, and a bushing body. The bottom of the first fixing ring and the bottom of the second fixing ring are both fixedly connected to the stern shaft. The first fixing ring is connected to the rear end of the bushing body by bolts, and the second fixing ring is connected to the front end of the bushing body by bolts.

[0016] As a preferred embodiment of the present invention, a first sealing ring is provided at the rear end bottom of the bushing body, and the first sealing ring is sandwiched between the bushing body and the first fixing ring; a second sealing ring is provided at the front end bottom of the bushing body, and the second sealing ring is sandwiched between the bushing body and the second fixing ring.

[0017] Compared with the prior art, the stern shaft sealing device of this invention has the following advantages:

[0018] In this embodiment of the invention, the first sealing lip prevents water from outside the hull from entering the sealing cavity, the second sealing lip prevents lubricating oil from the lubricating oil cavity of the stern tube from entering the sealing cavity, and the third sealing lip further enhances the sealing effect. This completely separates water from outside the hull from the lubricating oil in the lubricating oil cavity. Moreover, the overall structure is compact, using one stern tube sealing ring to replace multiple sealing rings in existing sealing devices, which reduces the length of the entire stern tube sealing structure, further improves the cantilever beam effect of the propeller on the stern tube, reduces stress concentration at the rear end of the stern tube bearing, and improves the wear at the end of the stern tube white alloy bearing. It also reduces costs and provides a good sealing effect. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the existing simplex leather cup sealing structure;

[0020] Figure 2 This is a schematic diagram of the stern shaft sealing device provided in an embodiment of the present invention;

[0021] In the figure, 1 is the stern shaft seal ring; 11 is the main body; 12 is the first sealing lip; 13 is the second sealing lip; 14 is the third sealing lip; 15 is the connecting part; 151 is the locking protrusion; 2 is the bushing; 21 is the first fixing ring; 22 is the second fixing ring; 23 is the bushing body; 24 is the first sealing ring; 25 is the second sealing ring; 26 is the bolt; 3 is the stern shaft tube connector; 31 is the first connecting ring; 32 is the second connecting ring; 321 is the baffle; 33 is the fixing bolt; 34 is the sealing gasket; 4 is the stern shaft; 5 is the stern shaft tube; 6 is water; 7 is lubricating oil; 8 is the sealing ring. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., used to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] like Figure 2 As shown in the preferred embodiment of the present invention, a preferred embodiment of a stern shaft sealing device includes a stern shaft sealing ring 1 and a bushing 2 encircling the stern shaft 4. The bushing 2 has a sealing cavity that seals with the stern shaft sealing ring 1. The stern shaft sealing ring 1 includes a main body 11, a first sealing lip 12, a second sealing lip 13, a third sealing lip 14, and a connecting portion 15 connected to the stern shaft tube 5. The first sealing lip 12 and the second sealing lip 13 are respectively connected to the front and rear sides of the main body 11. The sealing lip 14 and the connecting part 15 are respectively connected to the inner and outer sides of the main body 11. The first sealing lip 12 is radially in contact with the rear wall of the sealing cavity and the lip of the first sealing lip 12 faces outward. The second sealing lip 13 is radially in contact with the front wall of the sealing cavity and the lip of the second sealing lip 13 faces the lubricating oil cavity in the stern tube 5. The third sealing lip 14 is axially in contact with the bottom wall of the sealing cavity and the lip of the third sealing lip 14 faces the side of the first sealing lip 12.

[0025] Therefore, the present invention can prevent water 6 from outside the hull from entering the sealing cavity through the first sealing lip 12, prevent lubricating oil 7 from entering the lubricating oil cavity of the stern tube 5 through the second sealing lip 13, and further enhance the sealing effect through the third sealing lip 14. This can completely separate the water 6 from outside the hull from the lubricating oil 7 in the lubricating oil cavity. Moreover, the overall structure is compact, and a single stern tube sealing ring 1 replaces multiple sealing rings in the existing sealing device, which reduces the length of the entire stern tube 4 sealing structure. This further improves the cantilever beam effect of the propeller on the stern tube 4, reduces the stress concentration generated at the rear end of the stern tube bearing of the stern tube 4, and improves the wear of the white alloy bearing end of the stern tube 4. In addition, it reduces costs and has a good sealing effect.

[0026] For example, the first sealing lip 12, the second sealing lip 13, and the third sealing lip 14 are all pre-compressed and installed in the sealing cavity. This ensures that even if the first sealing lip 12, the second sealing lip 13, and the third sealing lip 14 are worn, the pre-compressed first sealing lip 12, the second sealing lip 13, and the third sealing lip 14 can automatically and in real time compensate for the wear, preventing leakage and effectively ensuring a good sealing effect of the stern shaft 4 seal.

[0027] Specifically, the stern shaft seal 1 is an integrally molded rubber stern shaft seal 1, ensuring excellent overall sealing performance. The stern shaft seal 1 can be made of rubber materials with excellent water resistance, oil resistance, and heat resistance, such as fluorinated rubber. The first sealing lip 12, the second sealing lip 13, and the third sealing lip 14 are all hook-shaped, and their cross-sectional shapes are similar to those of the simplex cup.

[0028] For example, the main body 11 is quadrilateral in shape, and the first sealing lip 12, the second sealing lip 13, the third sealing lip 14 and the connecting part 15 are respectively connected to the four corners of the main body 11, thereby improving the connection stability between the first sealing lip 12, the second sealing lip 13, the third sealing lip 14 and the connecting part 15 and the main body 11; in this embodiment, the main body 11 is square in shape.

[0029] For example, the connecting part 15 is connected to the stern tube 5 via a stern tube connector 3. The stern tube connector 3 includes a first connecting ring 31, a second connecting ring 32, and a fixing bolt 33. The connecting part 15 is sandwiched between the first connecting ring 31 and the second connecting ring 32. The fixing bolt 33 passes through the first connecting ring 31 and the second connecting ring 32 in sequence and connects to the end of the stern tube 5. This effectively fixes the connecting part 15 on the stern sealing ring 1 to the stern tube 5 via the stern tube connector 3, and the clamping of the connecting part 15 by the first connecting ring 31 and the second connecting ring 32 ensures good connection sealing. Preferably, the first connecting ring 31 and the second connecting ring 32 are flanges.

[0030] Furthermore, the connecting part 15 is provided with locking protrusions 151 on both the front and rear sides, and the first connecting ring piece 31 and the second connecting ring piece 32 are provided with locking grooves that engage with the locking protrusions 151. This enables the locking protrusions 151 on the connecting part 15 to quickly position and engage with the first connecting ring piece 31 and the second connecting ring piece 32, ensuring the accurate installation position of the connecting part 15.

[0031] Preferably, a sealing gasket 34 is sandwiched between the second connecting ring 32 and the end face of the stern tube 5. The sealing gasket 34 effectively seals the gap between the second connecting ring 32 and the end face of the stern tube 5, preventing water 6 outside the hull from seeping into the lubricating oil 7 in the lubricating oil chamber.

[0032] Furthermore, the second connecting ring 32 is provided with a baffle 321 extending toward the inner wall of the stern tube 5, so that the baffle 321 can effectively block the sealing gasket 34 located on one side of the inner wall of the stern tube 5, thereby further improving the sealing effect.

[0033] For example, the bushing 2 includes a first fixing ring 21, a second fixing ring 22, and a bushing body 23. The bottom of the first fixing ring 21 and the bottom of the second fixing ring 22 are both fixedly connected to the stern shaft 4. The first fixing ring 21 is connected to the rear end of the bushing body 23 by bolts 26, and the second fixing ring 22 is connected to the front end of the bushing body 23 by bolts 26, facilitating the fixing and installation of the bushing 2. Further, a first sealing ring 24 is provided at the rear end bottom of the bushing body 23, and the first sealing ring 24 is sandwiched between the bushing body 23 and the first fixing ring 21; a second sealing ring 25 is provided at the front end bottom of the bushing body 23, and the second sealing ring 25 is sandwiched between the bushing body 23 and the second fixing ring 22, improving the sealing performance between the bushing body 23, the first fixing ring 21, and the second fixing ring 22. The first fixing ring 21 and the second fixing ring 22 are preferably flanges, and the first sealing ring 24 and the second sealing ring 25 are preferably O-rings.

[0034] In the description of this invention, it should be understood that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A stern shaft sealing device, characterized in that, The system includes a stern shaft seal ring and a bushing encircled on the stern shaft. The bushing has a sealing cavity that seals with the stern shaft seal ring. The stern shaft seal ring includes a main body, a first sealing lip, a second sealing lip, a third sealing lip, and a connecting portion that connects to the stern shaft tube. The first and second sealing lips are respectively connected to the front and rear sides of the main body. The third sealing lip and the connecting portion are respectively connected to the inner and outer sides of the main body. The first sealing lip makes radial contact with the rear wall of the sealing cavity, with its opening facing outwards. The second sealing lip makes radial contact with the front wall of the sealing cavity, with its opening facing the lubricating oil cavity inside the stern shaft tube. The third sealing lip... The lip makes axial contact with the bottom wall of the sealing cavity for sealing, and the lip opening of the third sealing lip faces the side of the first sealing lip; the first sealing lip, the second sealing lip, and the third sealing lip are all pre-compressed and installed in the sealing cavity; the main body is quadrilateral, and the first sealing lip, the second sealing lip, the third sealing lip, and the connecting part are respectively connected to the four corners of the main body; the connecting part is connected to the stern tube through the stern tube connector, the stern tube connector includes a first connecting ring, a second connecting ring, and a fixing bolt, the connecting part is sandwiched between the first connecting ring and the second connecting ring, and the fixing bolt passes through the first connecting ring and the second connecting ring in sequence and is connected to the end of the stern tube.

2. The stern shaft sealing device as described in claim 1, characterized in that, The stern shaft seal is an integrally molded rubber stern shaft seal, and the first sealing lip, the second sealing lip, and the third sealing lip are all hook-shaped.

3. The stern shaft sealing device as described in claim 1, characterized in that, Both the front and rear sides of the connecting part are provided with locking protrusions, and both the first connecting ring piece and the second connecting ring piece are provided with locking grooves that engage with the locking protrusions.

4. The stern shaft sealing device as described in claim 1, characterized in that, A sealing gasket is sandwiched between the second connecting ring and the end face of the stern tube.

5. The stern shaft sealing device as described in claim 4, characterized in that, The second connecting ring is provided with a baffle extending into the inner wall of the stern tube.

6. The stern shaft sealing device as described in claim 1, characterized in that, The bushing includes a first fixing ring, a second fixing ring, and a bushing body. The bottom of the first fixing ring and the bottom of the second fixing ring are fixedly connected to the stern shaft. The first fixing ring is connected to the rear end of the bushing body by bolts, and the second fixing ring is connected to the front end of the bushing body by bolts.

7. The stern shaft sealing device as described in claim 6, characterized in that, The bushing body has a first sealing ring at its rear end bottom, and the first sealing ring is sandwiched between the bushing body and the first fixing ring; the bushing body has a second sealing ring at its front end bottom, and the second sealing ring is sandwiched between the bushing body and the second fixing ring.

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