JPH0411918Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a stern tube shaft sealing device that prevents seawater from entering the ship and preventing oil from leaking out of the ship.

[Conventional technology]

Conventionally, as shown in Fig. 2, annular lip seals c, d, and e have been fixed to the inner periphery of the shaft hole of an annular case member b, which is arranged around the outer periphery of a shaft a that drives a propeller and is fixed to the hull side. , the outer lip seals c and d (closer to the seawater) are arranged to face outboard, and the inner lip seal e (on the hull side) is arranged to face inboard, and these lip seals c,
With respect to d and e, the sleeve liner f, which is airtightly sheathed on the shaft a, slides and rotates closely, preventing seawater from leaking into the ship and preventing stern tube bearing lubricating oil B (hereinafter referred to as inboard oil) from leaking into the ship. ) A stern tube shaft sealing device is known that is configured to prevent leakage of water overboard.

[Problem that the invention attempts to solve]

In the above configuration, the pressure of the in-flight oil B is generally set higher than the seawater pressure when fully loaded so that it is always higher than the seawater pressure from the perspective of preventing seawater A from leaking. Since the inner lip seal e is received, the lip seal e
The load on lip seals c and d is larger than that on other lip seals c and d. In addition, in recent years, as ships have become larger, the difference in water pressure has become larger, and the difference in seawater pressure between fully loaded and ballasted has become larger, resulting in an excessive load on the inner lip seal e, which is deteriorating the durability of the seal. In order to avoid this danger, the pressure of the in-board oil B is switched using two gravity tanks (not shown) for the stern tube bearing, a HIGH tank and a LOW tank. A means is required for approximating the load applied to the inner lip seal e to an appropriate value at each time of ballasting.

[Means for solving problems]

In view of the above-mentioned problems, the stern tube shaft sealing device of the present invention suppresses the excessive pressure of internal oil applied to the inner lip seal and extends the life of the seal. Among a plurality of lip seals that are fixed to the periphery and closely slide and rotate on the shaft or a sleeve liner that is airtightly packaged on the shaft, the inner circumference of the shaft hole of the case member is located on the inboard side of the inner lip seal that seals inboard oil. and an outer circumferential surface of the sleeve liner are closely opposed to each other via a booth, and a pumping force is generated inwardly of the ship by rotation of the shaft on at least one of the closely opposed circumferential surfaces. It has a configuration in which a spiral groove is formed that is inclined in the direction.

[Effect]

That is, according to the present invention, when the shaft rotates, the helical groove generates a pump pressure that causes the internal oil to be delivered from the space near the inner lip seal to the inside of the ship due to the screw propulsion reaction force, and the pump pressure is applied to the inner lip seal. It acts to reduce the pressure of the oil in the machine.

〔Example〕

Next, the specific structure and operation of the stern tube shaft sealing device of the present invention will be explained based on the embodiment shown in FIG.

Reference numeral 1 denotes a shaft that rotates a propeller (not shown) attached to the left side of the figure, 2 is a sleeve liner that is hermetically covered with the shaft 1, and an aft cover 3 is provided on the outside of the sleeve liner 2. , an annular case member 7 consisting of an adapter ring 4, an intermediate ring 5, and a casing 6.
is integrally fixed to. 10 and 11 are located on the inner peripheral side of the case member 7, respectively, and are attached to the aft cover 3.
and the adapter ring 4 and between the adapter ring 4 and the intermediate ring 5
This is a lip seal for preventing leakage, and inner diameter lip portions 10' and 11' into which the garter springs 12 and 13 are fitted and which slide into contact with the sleeve liner 2 protrude toward the seawater A side. Reference numeral 14 denotes an inner lip seal for preventing leakage of in-machine oil B, which is located on the inner circumferential side of the case member 7 and is clamped between the intermediate ring 5 and the casing 6. A garter spring 15 is fitted into the inner lip seal 14, which slides into contact with the sleeve liner 2. The inner diameter lip portion 14' projects toward the inboard oil B side (inside the ship). Further, on the inner periphery of the shaft hole of the casing 6 on the inboard side of the inner lip seal 14, an annular convex stepped portion 17 is formed which is close to the outer circumferential surface of the sleeve liner 2 via a booth 16. A rotating shaft 1 and a sleeve liner 2 are provided on the inner peripheral surface of the portion 17.
A spiral groove 19 is configured to feed the in-machine oil B, which rotates and flows due to its own viscosity, from the space 18 between the inner lip seal 14 and the convex step 17 to the inside of the ship (on the right side in the figure). is engraved.

Therefore, according to this embodiment having the above-mentioned configuration, the rotation of the shaft 1 (sleeve liner 2) generates a pumping force toward the inside of the ship in the spiral groove 19, so that the inside of the space 18 is The pressure of the in-machine oil B is reduced, and the load on the inner lip seal 14 is eased.

In this embodiment, the spiral groove is provided on the inner circumferential surface of the casing, but it goes without saying that the spiral groove may be provided on the outer circumferential surface of the sleeve liner or both circumferential surfaces.

[Effect of idea]

As explained above, the stern tube shaft sealing device of the present invention has a spiral groove on the inside of the inner lip seal that generates a pumping force toward the inside of the ship when the shaft rotates. The internal hydraulic pressure in the outer circumferential space of the lip seal is reduced, and the sliding load on the inner lip seal due to this pressure is reduced, which improves seal durability. In order to cope with the difference in seawater pressure during ballasting and ballasting, it is now possible to use only the HIGH tank instead of the conventional two-tank system of a HIGH tank and a LOW tank, and its practical value is extremely large. There is something.

[Brief explanation of the drawing]

FIG. 1 is a half-cut sectional view showing an embodiment of the stern tube shaft sealing device of the present invention, and FIG. 2 is a half-cut sectional view showing a conventional stern tube shaft sealing device. 1...shaft, 2...sleeve liner, 7
... Case member, 10, 11 ... Lip seal,
14...inner lip seal, 16...booth, 1
9...Spiral groove, B...In-flight oil.

Claims (1)

[Scope of utility model registration request] Among a plurality of lip seals that are fixed to the inner periphery of the shaft hole of an annular case member and closely slide and rotate on the shaft or a sleeve liner that is airtightly sheathed on the shaft, on the inboard side of the inner lip seal that seals inboard oil. , the inner circumferential surface of the shaft hole of the case member and the outer circumferential surface of the sleeve liner are closely opposed to each other via a booth, and at least one of the closely opposed circumferential surfaces is affected by the rotation of the shaft. A stern tube shaft sealing device characterized in that a spiral groove is formed that is inclined in a direction that generates a pumping force toward the inside of the ship.