JPH0642144Y2 - Emergency seal mechanism of stern tube shaft sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a stern tube shaft sealing device that seals a propeller shaft of a ship, and more particularly to an improvement of an emergency seal mechanism in a bearing oil seal.

[Conventional technology]

BACKGROUND ART Conventionally, as one type of stern tube shaft sealing device, there is one as illustrated in FIG.

This stern tube shaft sealing device is located outside a stern tube bearing 8 and is fixed to the ship body 2 and surrounds the propeller shaft 4.
It has a structure in which lip seals 12, 14, 16 and 18 made of an elastic body are held in a watertight manner on the inner periphery of.

Of these, the lip seals 12 and 14 near the stern are provided rearward with respect to the stern tube bearing 8, and the front surface thereof receives the pressure of the seawater A and is brought into sliding contact with the sleeve 10 externally mounted on the propeller shaft 4 to form a ship interior. It functions as a seal against seawater that prevents the ingress of seawater A into the sea.

Further, the lip seals 16 and 18 near the stern tube bearing 8 are provided in front of the stern tube bearing 8 to prevent the bearing oil B in the bearing oil chamber 20 from leaking from the shaft periphery to the outside of the ship. It is intended to function as a bearing oil seal.

In the chamber 22 formed between the lip seals 16 and 18 as the bearing oil seal, a pressure guiding hole 24 penetrating the casing 6 and a pressure guiding pipe 26 connected to the pressure guiding hole 24 and extending to the inside of the ship 26 are formed. A bearing oil pressure equal to the pressure of the bearing oil chamber 20 is normally applied via the, so that the lip seal 18 positioned closest to the stern tube bearing 8 is normally in an idling state and stands by as a preliminary seal. In this state, substantially only the lip seal 16 functions as a regular bearing oil seal.

If a problem such as damage occurs in the regular lip seal 16, the valve device (not shown) is operated to shut off the bearing hydraulic pressure to the chamber 22 and the standby state is maintained. The spare lip seal 18 and the bearing oil chamber 20
Since the differential pressure generated between the chamber 22 and the chamber 22 acts from the front,
It can function as a bearing oil seal.

[Problems to be solved by the device]

However, according to the above-mentioned conventional structure, since the bearing hydraulic pressure is applied to the chamber 22 for holding the auxiliary lip seal 18 in the standby state through the pressure guiding pipe 26, the piping of the pressure guiding pipe 26 is physically unsatisfactory. In a possible small vessel, the above-mentioned emergency seal mechanism could not be provided.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an emergency seal mechanism that does not require oil supply piping from the inside of the ship.

[Means for Solving the Problems]

In order to solve the above problems, the emergency sealing mechanism of the stern tube shaft sealing device according to the present invention includes a spare lip seal located closest to the stern tube bearing as a bearing oil seal, and a back side of the spare lip seal. In the stern tube shaft sealing device provided with the common lip seal located, the bearing oil chamber in front of the spare lip seal and the chamber in the back of the lip seal are communicated with each other through a pressure equalizing hole penetrating the casing, The valve chamber formed in the middle of the hole is provided with a bush that is connected to an embedded bolt screwed from the outside of the casing to open and close the pressure equalizing hole.

[Action]

According to the present invention, the bush is normally located at the retracted position in the valve chamber and the pressure equalizing hole is opened, and the spare lip seal closest to the stern tube bearing is pressure-balanced between the bearing oil chamber on the front side and the chamber on the rear side. Therefore, the seal pressure by the bearing oil does not act, and in the standby state, only the regular lip seal functions as a substantial bearing oil seal.

Also, if a malfunction occurs in the service lip seal, by operating the embedded bolt from the outside of the casing to close the pressure equalizing hole by moving the bush, the bearing oil chamber and the service lip seal may leak. The differential pressure generated between the pressure drop chamber and the chamber acts as a seal pressure from the front of the preliminary lip seal, and the preliminary lip seal functions as a bearing oil seal.

〔Example〕

The present invention will be described below with reference to an embodiment shown in FIGS. 1 and 2. In this embodiment, the parts corresponding to those in the prior art example are designated by the same reference numerals as those in FIG. 3, and the description thereof will be omitted.

FIG. 1 is a half-cut sectional view of a stern tube shaft sealing device equipped with an emergency sealing mechanism of the present embodiment, and FIG. 2 is an enlarged sectional view showing an essential part thereof.

28 and 30 are pressure equalizing holes formed through the casing member 6a on the innermost side (stern tube bearing 8 side) of the casing 6, and the both 28 and 30 are screws extending in the radial direction from the outer periphery of the casing member 6a. The holes 34 communicate with each other through a valve chamber 32 formed at the inner diameter side end. The pressure equalizing hole 28 has one end in the bearing oil chamber 20,
The other end is open to the inner peripheral wall of the valve chamber 32, and the pressure equalizing hole 30
Has an opening at one end in the chamber 22 at the back of the preliminary lip seal 18 and at the other end at the bottom surface of the valve chamber 32.

Reference numeral 36 denotes a cylindrical bush inserted in the valve chamber 32, and a pair of O-rings 38, 40 slidably contacting the inner peripheral wall of the valve chamber 32 on the outer peripheral surface thereof.
And a packing 42 is fixed to the end surface facing the bottom surface of the valve chamber 32, and is connected to the embedded bolt 44 with a hexagonal hole screwed into the screw hole 34 via a connecting rod 46. Therefore, the valve chamber 32 is movable in the axial direction. Reference numeral 48 in the figure denotes a bolt that closes the opening of the screw hole 34 on the outer periphery of the casing member 6a.

The operation of the above structure will be described below.
36 is normally in the retracted position shown in FIG.
0 is in an open state, and the pressure of the bearing oil chamber 20 is introduced into the chamber 22 on the back surface of the preliminary lip seal 18 through the pressure equalizing hole 28, the valve chamber 32, and the pressure equalizing hole 30. The spare lip seal 18 is in a standby state in which the front surface and the back surface are pressure-equalized and has almost no sealing function, and the regular lip seal 16 seals against the bearing oil B.

Here, if a problem such as damage occurs in the regular lip seal 16, after removing the bolt 48,
The embedded bolt 44 in the screw hole 34 is screwed inward from the outside of the casing member 6a with a wrench (not shown) or the like.
Then, the bush 36 connected to the embedded bolt 44 by the connecting rod 46 advances in the valve chamber 32 toward its bottom surface, and closes the opening 30a of the pressure equalizing hole 30 in the packing 42 at the tip of the bush 36. The opening 28a of the pressure equalizing hole 28 is closed between the O-rings 38 and 40 on the outer circumference.

Therefore, at this point, the introduction of the bearing oil pressure from the bearing oil chamber 20 to the chamber 22 is cut off, so that the pressure decreases due to leakage from the regular lip seal 16 due to damage or the like, and between the chamber 22 and the bearing oil chamber 20. The resulting differential pressure acts as a seal pressure from the front of the spare lip seal 18, and the spare lip seal 18 functions as a bearing oil seal in place of the regular lip seal 16.

According to the present embodiment described above, the casing member 6a is provided with the pressure equalizing holes 28 and 30 for short-circuiting the bearing oil chamber 20 and the chamber 22 on the rear surface of the auxiliary lip seal 18, and the bush 36 as a valve mechanism for opening and closing the pressure equalizing holes 28 and 30. With this configuration, the spare lip seal 18 is normally held in the standby state, and in the event of an emergency, the spare lip seal 18 is changed from the standby state to the sealed state.Therefore, pressure piping from the inside of the ship is not required. Is characterized by.

The present invention is not limited to the above embodiment. For example, the bush 36 only needs to be able to block between the pressure equalizing holes 28, 30, and other detailed structures can be variously changed.

[Effect of device]

As described above, in the emergency sealing mechanism of the stern tube shaft sealing device according to the present invention, the casing is provided with the pressure equalizing hole that communicates the bearing oil chamber with the chamber on the back of the auxiliary lip seal, and the bush is operable from the outside. By opening and closing, the standby state of the standby lip seal is maintained, and in the event of an emergency, the standby lip seal is changed from the standby state to the sealed state, and pressure piping from the inside of the vessel unlike the conventional case is not required. Therefore, there is an excellent effect that the mechanism is downsized and simplified and can be mounted on a small boat.

[Brief description of drawings]

FIG. 1 is a half sectional view showing a stern tube shaft sealing device equipped with an emergency seal mechanism according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of the same main part, and FIG. 3 is a conventional emergency seal. It is a half section view showing a stern tube shaft sealing device equipped with a mechanism. 4 propeller shaft, 6 casing, 8 stern tube bearing 10 sleeve, 16 regular lip seal 18 spare lip seal, 20 bearing oil chamber 22 chamber, 28,30 pressure equalizing hole, 32 valve chamber 34 screw hole, 36 bush 44 embedded bolt, 46 connecting rod

Claims (1)

[Scope of utility model registration request] 1. A plurality of lip seals, which are in sliding contact with a sleeve mounted on a propeller shaft, are held on the inner circumference of a casing, and a spare lip seal positioned closest to the stern tube bearing as a bearing oil seal and a spare lip seal of the spare lip seal are provided. In the stern tube shaft sealing device having a regular lip seal located on the back side,
The bearing oil chamber on the front side of the spare lip seal and the chamber on the back side of the lip seal communicate with each other through a pressure equalizing hole penetrating the casing, and from the outside of the casing to a valve chamber formed in the middle of the pressure equalizing hole. An emergency sealing mechanism for a stern tube shaft sealing device, comprising a bush that is connected to a screwed embedded bolt to open and close the pressure equalizing hole.