JPH08230789A - Stern tube sealing equipment - Google Patents

Abstract

PURPOSE: To make power transmission efficiency more excellent compared with a stern tube seal by the gland packing and more effectively prevent the water leakage from a seal into a ship during a large whirling of a propulsion shall compared with the stem tube seal by the conventional rubber bellows. CONSTITUTION: A rubber cylindrical bellows body 3 provided with a ring-shaped flange bellows part 3a on a rear part of the outer circumference is housed at the prescribed position in the longitudinal direction of a propulsion shaft 4 to tightly fix its fore part 3b to the circumferential surface of the propulsion shaft, and a seal ring 6 to be brought into tight contact with a seal surface 2a in the radial direction provided on the fore part of a stern tube 1 in the slidable manner is concentrically fixed to the rear end surface. A cylindrical holder body 7 which surrounds the circumferential surface of the cylindrical bellows body and where the circumferential edge of the flange-shaped bellows part is brought into internal contact is provided to fix its forward part 7a to the propulsion shaft 7a, and a spring 9 to press a rear part 3c of the cylindrical bellows body rearward is provided inward of the holder body 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stern tube sealing device which is implemented in front of the stern tube of a relatively small boat such as a fishing boat or a leisure boat.

[0002]

2. Description of the Related Art A propulsion shaft is penetrated to the outside of a ship through a stern pipe, but since a radial gap is provided between the stern pipe and the propulsion shaft, seawater tries to enter the inside of the ship through this gap. In order to prevent this, a stern tube sealing device is conventionally provided in the front part of the stern tube.

A stern tube sealing device for a relatively small ship uses a ring-shaped rubber bellows in which a gland packing is brought into close contact with the peripheral surface of the propulsion shaft to ensure watertightness or to surround the peripheral surface of the propulsion shaft. It is designed to ensure water tightness.

[0004]

In the above-mentioned conventional stern tube sealing device, when the gland packing is used, excessive leakage of water occurs due to the passage of time, or the propulsion shaft is worn due to sliding contact of the gland packing, Alternatively, there is a problem that the sliding contact of the gland packing causes a large amount of friction to reduce the power transmission efficiency, and the rubber bellows has a structure in which the elastic force of the rubber is the main component to keep the watertightness. Water leakage is excessive due to deterioration, and it is difficult to ensure watertightness when the radial displacement of the propulsion shaft during rotation and the change in the bending angle of its axis become large due to wear of bearings in the stern tube. There are problems such as

An object of the present invention is to provide a stern tube sealing device which can solve the above problems.

[0006]

In order to achieve the above object, the present invention has a rubber cylindrical bellows body having a ring-shaped brim-shaped bellows portion at the rear portion of its outer periphery, and is fitted onto a specific position in the longitudinal direction of a propulsion shaft. The front part is fixed to the peripheral surface of the propulsion shaft in a dense manner, and the rear end surface is provided with a seal ring which is slidably brought into close contact with the radial seal surface provided on the front part of the stern tube. A cylindrical holder body that is fixed and, on the one hand, surrounds the peripheral surface of the cylindrical bellows body and is inscribed at the peripheral edge of the collar-shaped bellows portion is provided, and the front portion of the cylindrical holder body is fixed to the propulsion shaft. A spring for pressing the rear portion of the cylindrical bellows body to the rear is provided inside.

[0007]

The seal ring has its rear end face slidably displaced and water-tightly pressed against the seal face by the extension force of the spring. In this state, the sealing surface, the seal ring, and the rubber cylindrical bellows block the gap between the stern tube and the propulsion shaft.

The position of the propulsion shaft is displaced forward and backward by a specific dimension between forward rotation and reverse rotation. In such a case, the rubber cylindrical bellows body has its center line in relation to the spring force. It expands and contracts in the direction to ensure close contact between the seal ring and the seal surface.

Further, when the bearing in the stern tube is worn, the propulsion shaft is largely displaced in the radial direction during its rotation, and at the same time, the deflection angle of its own axis is largely changed to cause an unstable whirling state. Of the rubber cylindrical bellows body is elastically deformed in the direction of its centerline in a universal direction in relation to the spring force, and the ring-shaped brim bellows part is supported by the cylindrical holder body at its periphery. Effectively resisting the rear irregular radial displacement, the seal ring is stably held in close contact with the sealing surface.

Further, since the sliding contact portion of the propulsion shaft during rotation is only the contact portion between the seal ring and the seal surface, wear which is difficult to repair due to the sliding contact of the propulsion shaft is avoided, and the sliding contact portion is The frictional force is greatly reduced compared to the conventional gland packing.

[0011]

1 is a longitudinal sectional view showing a state where a propulsion shaft rotates in a forward direction according to the device of the present invention, and FIG. 2 shows a longitudinal section showing a state in which the propulsion shaft rotates toward a reverse side according to the device. Floor plan,
3 is a cross-sectional view showing a section xx in FIG. 2, and FIG. 4 is a section x1 in FIG.
It is sectional drawing which shows -x1 part.

In the figure, 1 is a stern tube, 2 is a ring seat fixed to the front end surface of the stern tube 1 by a bolt, and the front surface of the ring seat 2 is a flat sealing surface 2a along the radial direction of the stern tube 1. ing. At this time, the ring sheet 2 is preferably made of phosphor bronze, and the sealing surface 2a is more preferably made of ceramic from the viewpoint of wear resistance.

Reference numeral 3 denotes a rubber cylindrical bellows body integrally formed of rubber (NBR) or a suitable synthetic resin, and is provided with a ring-shaped brim-shaped bellows portion 3a near the rear end of the outer periphery. At the time of its mounting, the front portion 3b is fitted to the propulsion shaft 4 inserted in the stern tube 1 at a specific position in the longitudinal direction.
Is closely contacted with the peripheral surface of the propulsion shaft 4 and the spring 5 is fitted in the groove on the outer peripheral surface of the front portion 3b so that the front portion 3b is fixed.

Reference numeral 6 is a seal ring made of a material such as tetrafluororesin or phenol resin to which Kevlar is added. The front end portion 6a is buried concentrically with the rear end surface of the cylindrical bellows body 3 and The end portion 6b is to be brought into close contact with the sealing surface 2a. When mounting the end portion 6b, two notches k are provided on the rear end portion 6a as shown in FIG. A part of the cylindrical bellows body 3 is bited so that the seal ring 6 is not displaced in the cylindrical bellows body 3.

Reference numeral 7 denotes a cylindrical holder body made of a relatively hard material such as metal, which surrounds the entire peripheral surface of the cylindrical bellows body 3 and inscribes the peripheral edge of the flange-shaped bellows portion 3a. At the time of mounting, the propulsion shaft 4 is inserted into the shaft hole of the front portion 7a and fixed to the propulsion shaft 4 via the set bolt 8 screwed to the thick portion of the front portion 7a. The setting bolts 8 are preferably arranged symmetrically around the front portion 7a.

Therefore, the cylindrical bellows body 3 and the cylindrical holder body 7 are firmly and integrally fixed to the propulsion shaft 4. Therefore, specifically, the outer peripheral surface of the front end portion of the cylindrical bellows body 3 is formed. 4, a plurality of notches k1 are provided, and on the other hand, on the inner peripheral surface of the fitting hole m formed at the rear end of the shaft hole of the front portion 7a of the cylindrical holder body 7, a protrusion corresponding to the notch k1 is formed. m1 is provided, and the front end of the cylindrical bellows body 3 is fitted in the fitting hole m so that the protrusion m1 and the notch k1 are engaged with each other.

Reference numeral 9 denotes a spring for pressing the rear portion 3c of the cylindrical bellows body 3 rearward. The spring 9 is fitted onto the peripheral surface of the cylindrical bellows body 3 inside the cylindrical holder body 7 and has a front end 9a.
Is brought into contact with the inner surface of the front portion 7a of the cylindrical holder body 7, and the rear end 9b
Is brought into contact with a position radially inward of the collar-shaped bellows portion 3a. At this time, it is preferable that each end portion of the spring 9 is bent in a hook shape and a locking hole is provided at each abutting portion so as to be locked in the locking hole.

An example of use and operation of the apparatus of the present invention constructed as above will be described. When the present device is assembled to the propulsion shaft 4, the annular closed space surrounded by the cylindrical holder body 7 and the cylindrical bellows body 3 is filled with grease.

When the propelling shaft 4 is rotated forward, it is pushed by the propeller p fixed to the rear end of the propelling shaft 4 and moved forward by a dimension corresponding to the loose clearance in the axial direction.

For this reason, the rear end surface of the seal ring 6 mounted on the side of the propulsion shaft 4 tends to separate from the seal surface 2a, but the rear portion 3c of the cylindrical bellows body 3 moves backward due to its own elasticity and the elasticity of the spring 9. Since the outer periphery of the collar-shaped bellows portion 3a slides rearward on the inner surface of the cylindrical holder body 7, the rear portion 3c is displaced rearward, and the seal ring 6 is still suitable for the sealing surface 3a. It is pressed by force.

As a result, the seal ring 6 has the seal surface 2
It comes into close contact with a and is slidably displaced around the propulsion shaft 4 on the seal surface 2a. Therefore, the seal ring 6 and the cylindrical bellows body 3 are inwardly moved through the bearing gap of the stern tube 1. The invading seawater is prevented from excessively leaking into the ship through the contact points of the seal ring 6 and the seal surface 2a during the rotation of the propulsion shaft 4, and the seawater is also absorbed in the front part b of the cylindrical bellows body 3. Reach, but the front 3 of this
Since b is in close contact with the peripheral surface of the propulsion shaft 4, it does not leak from this contact portion.

When the bearing 1a in the stern tube 1 is greatly worn, the propulsion shaft 4 is largely displaced in the radial direction, and at the same time, the bending angle of the axis line is variously changed to cause irregular whirling. And when it comes to this,
If no measures are taken, the position of the seal ring 6 becomes unstable, and the close contact with the seal surface 2a tends to be lost. However, in this device, the peripheral wall of the cylindrical bellows body 3 freely expands and contracts in the direction of the center line thereof, and at the same time, the collar-shaped bellows portion 3a bends and its peripheral edge slides on the inner surface of the cylindrical holder body 7, so that the seal ring 6 is propelled. The shaft 4 is displaced so as to respond to an arbitrary front-back movement and a bending angle, and the rear portion 3c of the cylindrical bellows body 3 is supported by the cylindrical holder body 7 via the collar-shaped bellows portion 3a to prevent excessive displacement in the radial direction. Effectively limited. Thus, the seal ring 6 is stably held at an appropriate position and closely contacts the seal surface 2a to reliably prevent excessive water leakage.

While the cylindrical bellows body 3 is rotating, even if another object approaches the cylindrical bellows body 3 due to carelessness, the cylindrical holder body 7 prevents the other object from directly contacting the cylindrical bellows body 3 and the cylindrical bellows body 3 Prevent damage to the equipment.

When the propulsion shaft 4 is rotated in the reverse direction, the propulsion shaft 4 is pulled by the propeller p and moved backward by a dimension corresponding to the loose clearance.

In this case, the rear end surface of the seal ring 6 mounted on the side of the propulsion shaft 4 tends to be excessively pressed against the seal surface 2a, but the cylindrical bellows body 3 is compressed by the elasticity of itself and the spring 9. Since the periphery of the collar-shaped bellows portion 3a slides forward on the inner surface of the cylindrical holder body 7, the rear portion 3c of the bellows body 3 maintains the state in which the seal ring 6 is pressed against the sealing surface 2a. To do.

Thus, the seal ring 6 is brought into contact with the seal surface 2a with an appropriate pressure, and at the same time, the propulsion shaft 4 moves on the seal surface 2a.
Since it is smoothly slidably displaced around, excessive leakage of seawater into the ship is prevented as in the above, and excessive friction and wear of the seal ring 6 are prevented.

When the propulsion shaft 4 is switched from the forward drive to the reverse drive or vice versa, the propulsion shaft 4 temporarily causes irregular and violent whirling. In this case, the bearing 1 of the stern tube 1 is also generated.
Each part operates properly according to the action when a is greatly worn, and the seal ring 6 is always in close contact with the seal surface 2a at an appropriate pressure, which also prevents excessive leakage of seawater into the ship. To be done.

When the rear end surface of the seal ring 6 is worn, it is replaced together with the cylindrical bellows body 3.

[0029]

According to the present invention constructed as described above, since the seal ring and the seal surface are linked to each other to prevent water leakage, the propulsion shaft itself is not worn, and the conventional gland packing is used. Compared to the above, the increase in water leakage is less likely to occur over time, the rotational friction resistance of the propulsion shaft is reduced, and the power transmission efficiency is improved, and the propulsion shaft is enlarged due to wear of bearings in the stern tube. Even if it shakes around, the seal ring can be expanded and contracted in the center line direction of the cylindrical bellows body, the elastic force of the spring, and the radial support force between the cylindrical holder body and the flange-shaped bellows. The seal surface can always be brought into close contact with the seal surface at an appropriate pressure. Therefore, excessive leakage of water outside the ship into the inside of the ship through this contact point can be reliably prevented. And it is become, more it becomes the cylindrical holder body to prevent damage of the blocking to the bellows body that another object in the cylindrical bellows member is in direct contact.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a state when a propulsion shaft rotates toward a forward side according to the device of the present invention.

FIG. 2 is a vertical cross-sectional view showing a state when the propulsion shaft rotates to the reverse side according to the device of the present invention.

FIG. 3 is a cross-sectional view showing a section xx in FIG.

FIG. 4 is a cross-sectional view showing an x1-x1 portion of FIG.

[Explanation of symbols]

 1 Stern tube 2a Sealing surface 3 Cylindrical bellows body 3a Collar type bellows part 3b Front part of cylindrical bellows body 3c Rear part of cylindrical bellows body 4 Propulsion shaft 6 Seal ring 7 Cylindrical holder body 7a Front part of cylindrical holder body 9 Spring

Claims (1)

[Claims] 1. A rubber cylindrical bellows body having a ring-shaped brim-shaped bellows portion at a rear portion of its outer periphery is externally fitted to a specific position in a longitudinal direction of a propulsion shaft, and its front portion is densely fixed to a peripheral surface of the propulsion shaft. A seal ring, which is slidably in close contact with the radial seal surface provided on the front portion of the stern tube, is fixed to the rear end surface in a substantially concentric manner, while the surrounding surface of the cylindrical bellows body is surrounded. In addition, a cylindrical holder body is provided in which the peripheral edge of the flange-shaped bellows portion is inscribed, and the front portion of the cylindrical holder body is fixed to the propulsion shaft. A stern tube sealing device comprising a spring for pressing.