JP2007230381A - Seal structure of impeller shaft in water jet propulsion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent breakage of an impeller shaft by wetting all peripheries and all surfaces of a normal seal ring by supplying cooling water even when an impeller shaft of a water jet propulsion device has a non-submerged part in detaining a vessel. <P>SOLUTION: This seal structure of the impeller shaft of the water jet propulsion device to seal the impeller shaft with the front normal seal ring and a rear emergency seal body stored in a seal housing provided in the middle by extending the impeller shaft to drive an impeller arranged in an intake duct formed on a hull forward with a space in a protective pipe provided in the inside of the hull constitutes its characteristic feature of providing a filler hole to fill cooling water to cool the normal seal ring on the seal housing and communicating an upper part of the seal housing and the space in the protective pipe in the rear of the emergency seal body through to each other with a downtake pipe. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a seal structure for an impeller shaft in a water jet propulsion device attached to a ship.

  2. Description of the Related Art In recent years, with the demand for speeding up ships, the number of ships that obtain propulsive force with the water jet propulsion device disclosed in Patent Document 1 below is increasing. In this water jet propulsion device, an intake duct having a water intake at the bottom of the ship is formed in the hull, and an impeller that is forcibly driven is arranged in the intake duct. It is ejected as a jet jet and propulsion is obtained by its reaction force. Therefore, the shallow structure of the flooded water is possible, and there is an advantage that it can navigate even in shallow water. In fact, both the impeller and the impeller shaft that drives the impeller may be in a state where only about half of them are submerged.

  In this case, the impeller shaft is drawn into the hull and connected to the engine. However, a seal structure is required at the drawn-in portion to prevent water from entering. FIG. 4 is a cross-sectional view of this seal structure. The impeller shaft 1 extends forward through a protective tube 2 provided in the hull, and a seal housing 3 is provided in the middle thereof. The front is provided with a service seal ring 4 and an emergency seal body 5 that is operated in an emergency from the front. Of these, the regular seal ring 4 is fixedly fitted to the impeller shaft 1, and on the rear surface of the sliding ring 6 that is attached to the seal housing 3 and fitted in a non-contact state to the impeller shaft 1. It is in contact. At this time, since the contact portion between the normal seal ring 4 and the sliding ring 6 generates heat, cooling water is injected from the injection port 3a to be cooled.

  On the other hand, the emergency seal body 5 is used in an emergency such as when there is a large amount of water, and is composed of a non-contact arrangement of a flexible ring body made of rubber or the like on the outer periphery of the impeller shaft 1. is doing. In an emergency, compressed air is supplied from the supply port 3b and is applied to the outer periphery of the emergency seal body 5, which is contracted and the impeller shaft 1 is tightened and sealed. However, the emergency seal body 5 has a great sealing effect, but is assumed to be used only while the impeller shaft 1 is stopped, and may be damaged if used while rotating. It is a thing.

With the above configuration, when the impeller shaft 1 is stopped for a long time due to a stoppage or the like, the non-submerged portion of the service seal ring 4 dries, and at this time, impurities in the water solidify and adhere to the surface of the service seal ring 4. . When the impeller shaft 1 is re-driven in such a state, the solidified product damages the surface of the regular seal ring 4 and loses the sealing function. In order to prevent this, cooling water may be supplied even when the ship is stopped. However, since the emergency seal body 5 behind the ship is not in contact with the impeller shaft 1, it flows out of the ship through this gap. Therefore, it is impossible to wet the entire surface of the regular seal ring 4. Therefore, it seems that the emergency seal body 5 should be contracted, but if this is done, the pressure in the seal housing 3 will increase and the cooling water cannot be filled.
Japanese Patent Laid-Open No. 5-155811

  The present invention solves the above problems, and even when the ship is stopped when a non-submerged portion is generated on the impeller shaft, the entire circumference and the entire surface of the regular seal ring can be wetted so that cooling water can be supplied. It is what I did.

  Under the above problems, the present invention has a space in a protective tube provided in the hull for an impeller shaft for driving an impeller disposed in an intake duct formed in the hull according to claim 1. In the seal structure of the impeller shaft of the water jet propulsion unit that seals the impeller shaft with the forward service seal ring and the rear emergency seal body accommodated in the seal housing provided in the middle, the service seal ring is cooled An impeller shaft in a water jet propulsion device characterized in that an inlet for injecting cooling water is provided in the seal housing, and the upper portion of the seal housing and the space in the protective tube behind the emergency seal body are communicated with an escape pipe. The seal structure is provided.

  Further, the present invention is the above-described seal structure, wherein the overflow pipe described in claim 2 is replaced with a hole drilled in the quality wall of the seal housing and the tube wall of the protective pipe, and described in claim 3. 4. A means in which a second service seal ring is disposed between the service seal ring and the emergency seal body, and the liner is integrally attached to the outer periphery of the impeller shaft according to claim 3, and the service seal is attached to the outer periphery of the liner. Means are provided in which a ring, a second service seal ring, and an emergency seal body are arranged.

  According to the means of claim 1, if the emergency seal body is contracted when the ship is stopped, the seal housing is sealed, but the pressure inside is maintained at the atmospheric pressure in the protective pipe by the overflow pipe. The housing can be filled with cooling water. The cooling water leaking from the seal housing is discharged through the overflow pipe. At this time, since the overflow pipe is provided above the seal housing, the regular seal ring is always provided on the entire circumference and the entire surface. Will be wetted. The supply may be stopped after the cooling water is filled.

  According to the second aspect of the present invention, excess pipes and the like do not come out, and according to the third aspect, the second service seal ring replaces the emergency seal body. There is no need to shrink the sealing body. Therefore, even if the impeller shaft is rotated, the emergency seal body is not damaged. In addition, the second regular seal ring does not require so much pressure resistance, and an inexpensive one is sufficient. According to the fourth aspect of the present invention, wear of the impeller shaft due to the regular and second regular seal rings is avoided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, an outline of a water jet propulsion apparatus will be described. FIG. 5 is a plan view of the water jet propulsion device, and FIG. 6 is a cross-sectional view. This water jet propulsion device includes a nozzle 8 attached to the rear of the stern transom portion 7 and a pin 9 perpendicular to the rear of the nozzle 8. The steering deflector 10 is connected to be pivotable to the left and right. An intake duct 11 connected to the steering deflector 10 is formed in the hull from a water intake port 11a formed in the bottom of the ship, and an impeller 12 that is forcibly driven by the impeller shaft 1 is provided in the intake duct 11. .

  At the rear of the steering deflector 10, there is provided a reverse deflector 13 that changes the amount of deflection and the vertical direction after the jet jet pressurized by the impeller 12 collides. The reverse deflector 13 can turn up and down around a horizontal pin 14 provided on the steering deflector 10, and this rotation is interposed between the reverse deflector 13 and the steering deflector 10. This is done by the first hydraulic cylinder 15. Further, second and third hydraulic cylinders 16 and 17 for rotating the steering deflector 10 to the left and right are interposed between the left and right portions of the steering deflector 10 and the left and right portions of the nozzle 8.

  Therefore, when the first hydraulic cylinder 15 is expanded and contracted, the posture of the reverse deflector 13 is changed, and as a result, the boat speed and the traveling direction can be adjusted. That is, when the reverse deflector 13 is lowered and the steering deflector 10 is fully opened, the full speed forward is achieved. When the backward deflector of the jet jet is limited by raising the reverse deflector 13, the ship speed is reduced accordingly. Further, when the reverse force due to the forward reversal of the jet jet exceeds the forward force due to the backward jet by raising the jet flow further, the reverse drive is performed. On the other hand, when the second and third hydraulic cylinders 16 and 17 are expanded and contracted, the direction of the steering deflector 10 is changed and the vehicle can turn at an angle corresponding to the angle.

  The above impeller shaft 1 extends forward through a protective tube 2 extending from the intake duct 11 into the hull and is connected to an engine (not shown). A seal housing 3 in which the emergency seal body 5 and the like are accommodated is provided to constitute a seal structure. FIG. 1 is a cross-sectional view showing a seal structure according to the present invention. First, an inlet 18 is formed in the seal housing 3, and a pipe 19 is connected thereto so that cooling water can be injected. Then, a space 20 between the protective tube 2 and the impeller shaft 1 behind the seal housing 3 and the emergency seal body 5 is communicated with the escape pipe 21. In this example, the overflow tube 21 is installed outside the protective tube 2. However, a hole (not shown) is formed in the chamber wall of the seal housing 3 and the tube wall of the protective tube 2, and the overflow tube 21 is formed in this hole. May be substituted, and in that case, piping can be omitted. In this case, in order to fill the inside of the seal housing 3 with the cooling water, it is preferable that the position of the overflow pipe 21 is set to the highest position of the seal housing 3.

  As described above, when the ship is stopped or the like, the emergency seal body 5 is squeezed and the cooling water is injected into the seal housing 3 from the pipe 19 to fill the seal housing 3 fully. At this time, since the inside of the seal housing 3 communicates with the space (atmospheric pressure) by the overflow pipe 21, this is possible. Moreover, even if it supplies a little too much, since a surplus water can be escaped from the overflow pipe 21, a full state does not change. In this state, even if the supply of the cooling water is stopped, the cooling water fills the seal housing 3 to the full, and as a result, the wet state can be maintained over the entire circumference and the entire surface of the regular seal ring 4. Therefore, even if the impeller shaft 1 is driven again (at this time, the emergency seal body 5 is released), the service seal ring 4 is not damaged.

  FIG. 2 is a cross-sectional view showing another example of the present invention. In this example, a second regular seal ring 22 is provided at a position in front of the emergency seal body 5 in the seal housing 3. According to this, since it is not necessary to squeeze the emergency seal body 5 when the ship is stopped, the flexibility function of the emergency seal body 5 can be maintained and there is no problem even if the impeller shaft 1 is rotated. Further, since the second common seal ring 22 used here does not need to be so pressure-resistant, an inexpensive one is sufficient and the cost can be reduced.

  FIG. 3 is a cross-sectional view showing still another example of the present invention. In this example, the impeller shaft 1 at the place where the service seal ring 4, the second service seal ring 22 and the emergency seal body 5 act is shown. The liner 23 is integrally attached to the outer periphery. According to this, since the impeller shaft 1 does not slide with the regular seal ring 4, the second regular seal ring 22, and the emergency seal body 5, there is an advantage that the surface is not engraved and the durability is high. However, although the liner 23 is worn, the replacement thereof can be performed faster and cheaper than the replacement of the impeller shaft 1. Further, the overflow pipe 21 may be provided with a stop valve 24 and a check valve (not shown) for preventing backflow. This is to prevent the hull from swinging during inspecting and repairing, resulting in flooding, and seawater from flowing back through the overflow pipe 20 and entering the seal housing 3.

It is sectional drawing of an example of the seal structure which concerns on this invention. It is sectional drawing of the other example of the seal structure which concerns on this invention. It is sectional drawing of the other example of the seal structure which concerns on this invention. It is sectional drawing of the prior art example of a seal structure. It is a top view of a water jet propulsion device. It is sectional drawing of a water jet propulsion apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Impeller shaft 2 Protective tube 3 Seal housing 3a Cooling water inlet 3b Compressed air supply port 4 Regular seal ring 5 Emergency seal body 6 Sliding ring 7 Stern transom part 8 Nozzle 9 Pin 10 Steering deflector 11 Intake duct 11a Intake Duct inlet 12 Impeller 13 Reverse deflector 14 Pin 15 First hydraulic cylinder 16 Second hydraulic cylinder 17 Third hydraulic cylinder 18 Inlet 19 Pipe 20 Space 21 Overflow pipe 22 Second service seal ring 23 Liner 24 Stop valve

Claims (4)

  The front of the impeller shaft that drives the impeller disposed in the intake duct formed in the hull is extended forward through the protective tube provided in the hull and accommodated in the seal housing provided in the middle In a seal structure of an impeller shaft of a water jet propulsion device that seals an impeller shaft with a seal ring and a rear emergency seal body, an inlet for injecting cooling water for cooling a normal seal ring is provided in the seal housing, and the seal housing An impeller shaft seal structure in a water jet propulsion device, characterized in that the upper part of the air pipe and the space in the protective pipe behind the emergency seal body are connected by a discharge pipe.   2. The impeller shaft seal structure in a water jet propulsion apparatus according to claim 1, wherein the overflow pipe is substituted by a hole formed in the quality wall of the seal housing and the pipe wall of the protective pipe.   The seal structure of the impeller shaft in the water jet propulsion device according to claim 1 or 2, wherein a second common seal ring is disposed between the normal seal ring and the emergency seal body.   The impeller in the water jet propulsion apparatus according to any one of claims 1 to 3, wherein a liner is integrally attached to an outer periphery of the impeller shaft, and a normal seal ring, a second normal seal ring, and an emergency seal body are disposed on the outer periphery of the liner. Shaft seal structure.