HK1020927B - Vertical water-jet propulsion device - Google Patents

Description

Vertical hydraulic jet propulsion unit

The present invention relates to a vertical hydraulic jet propulsion unit having a structure capable of reducing the rotational force required to rotate a housing.

The vertical hydraulic jet propulsion unit is provided with a water inlet and a water outlet which are flush with the bottom of the ship. The device that does not project out of the bottom of the vessel can be conveniently applied to a special vessel for shallow water work, such as a floating crane vessel, which cannot guarantee sufficient immersion of the propeller in the water due to its shallow draft, nor can it be equipped with a conventional tunnel thruster. Japanese unexamined published patent application Nos. 6-278692, 6-2866937 and 52882, 8-58689 disclose the prior art of such vertical hydraulic jet propulsion devices. The vertical hydrojet propulsion unit allows the housing body to include a water outlet that can be rotated in any direction through a 360 ° range, thereby generating a propulsion force in any selected direction, thereby improving the maneuverability of the ship.

Fig. 6 is a sectional view of the vertical type hydraulic jet propulsion device disclosed in the above-mentioned japanese unexamined patent application publication No. 7-52882. Fig. 7 is a plan view seen from one point of the diffuser.

As shown in the drawing, the discharged water flow sucked from the water inlet 53 of the central portion of the bottom 52a of the housing 52 flows upstream of the impeller 51 to join the rotating water flow generated by the rotation of the impeller 51. The diffuser 54 downstream of the propeller 51 changes the direction of the rotating water flow by the blades 55, and changes the direction of the rotating water flow by the action of the blades 55 to flow out in the radial direction at the outlets of the blades. Due to the presence of the rotating water flow, if the discharged water flow enters the pressure chamber on the housing 52, the rotational energy causes a frictional loss between the discharged water flow and the surface of the housing 52, resulting in a large energy loss. As for the function of the diffuser 54, since it is designed such that the section of the water flow path is gradually increased, the kinetic energy of the water flow is gradually converted into pressure energy, thereby increasing the thrust. The diffuser 54 provided with vanes 55 is an integral part of the vertical hydrojet propulsion unit.

According to the conventional vertical hydrojet propulsion unit described above, the diffuser 54 is integral with or mounted integrally on the housing 52. Because of this, the device is structured such that both the housing 52 and the diffuser 54 are driven to rotate by the steering motor 56.

As shown in fig. 7, the blades 55 of the diffuser 54 generate a rotational force (rotational moment) Y in the arrow direction due to the reaction force F of the water flow. This rotational force is so great as to enable the housing 52 to rotate 360 in any direction and significantly affect the determination of the capacity of the steering motor. That is, if the housing 52 is rotated by the manipulation motor 56 and the diffuser 54 is rotated in the direction of the rotational force (torque) Y applied thereto as indicated by the arrow in fig. 7, then the housing 52 is rotated and the manipulation motor 56 is rotated with a small power (conversely, it is required to stop the rotation thereof by manipulating the motor). On the other hand, if the diffuser 54 is rotated in the opposite direction, the required force is to overcome the sum of the frictional resistance and the moment created by the total inertial force of the housing; the second is the rotational moment generated by the water flow, which is much greater than the first two forces. The capacity of the steering motor is determined by the power. Power consumption is an important factor, especially for barges with lower power generation capacity. From the initial investment and operating cost considerations, the lower the power consumption, the better. The steering motor needs to be installed in a limited space, and therefore, the capacity of the motor is also required to be reduced to a small value, and the size of the motor is also required to be as small as possible. In the prior art mentioned above, the housing 52 is fitted with a propeller shaft seal 57, as shown in FIG. 6. If the housing 52 is rotated in the opposite direction to the impeller 51, the relative peripheral speed of the shaft seal contact portion is equal to the sum of its rotational speed and the impeller rotational speed. Because of this, the requirements for the shaft seal become very demanding and the service life of the shaft seal is correspondingly shortened.

According to the aforementioned japanese unexamined patent application publication No.7-52882, three drain ports are provided in the bottom of the housing 52, and the end surface of the intermediate drain port on the side close to the water inlet port is formed in an arc shape concentric with the water inlet port. The inside of each drain opening is not installed with a guide vane as will be described in the present application. It is clear that the above prior art does not take into account the effective flow of the discharged water flow in the horizontal direction. As a result, a portion of the water flow is significantly removed from directly below the bottom of the housing 52. Meanwhile, the torque required to rotate the housing assembly includes a rotational force against the kinetic energy of the discharged water flow, which is caused by the inertial force of the housing assembly and the like. If the flow rate and direction of the water flowing out from the side water outlets arranged on the two sides of the middle water outlet are not balanced, the rotating force has great influence on the torque, and the magnitude of the force becomes a decisive factor influencing the rotating torque. To avoid such a turning moment, the document 7-52882 teaches to define the size and position of the drain opening. In practice, the balance must be determined so that an undesired turning moment is likely to be generated in a particular direction. The capacity of the steering motor is also increased due to the increase of the rotational torque. In the above case, a greater water pressure or a greater power consumption will occur.

It is therefore an object of the present invention to provide a vertical hydrajet propulsion device having a structure that reduces the rotational force required to rotate a housing.

In one embodiment of the vertical hydraulic jet propulsion device of the present invention, the vertical hydraulic jet propulsion device includes a housing which can be rotated by an operating motor to push water upward from the bottom of the housing by rotation of a propeller so that the flow of water fills a pressure chamber provided on the housing through a diffuser and is discharged to the outside through a water discharge port provided at the bottom of the housing, wherein an inner ring supported by a hull side and having a propeller shaft inserted therein is provided at an upper portion of the housing to support the housing through a rotation bearing, and the diffuser is integrally mounted on or formed with the inner ring.

In this case the inner ring forms a fixed part supported by the hull side and the diffuser is separate from the hull to form a separate component. The rotational moment on the diffuser caused by the change of the direction of the water flow does not act on the housing. Furthermore, the diffuser remains stationary even if the housing rotates. Thus, the power of the motor required to rotate the housing itself is reduced.

Thus, if a gear box is associated with the lower end of a downwardly extending cylindrical inner ring mounted within the housing and the diffuser is integrally mounted at the lower end of the inner ring, a simpler construction is achieved.

Further, a propeller shaft seal may be installed between the fixed portion of the diffuser or inner ring and the rotating propeller shaft to isolate the seawater or lubrication chamber. Thus, the seawater and the lubricating oil can be prevented from entering and leaking between the seawater and the lubricating chamber.

Furthermore, if a rotary seal is installed between the stationary part of the diffuser or inner ring and the rotating housing, separating the seawater chamber from the lubrication chamber, the ingress and leakage of seawater and lubricating oil between the seawater chamber and the lubrication chamber can be avoided.

In addition, the contact surface between the diffuser and the inner ring inserted into the diffuser can be designed as a conical surface, so that the diffuser and the inner ring generate a thrust force with each other due to the rotational action of the reaction force of the water flow acting on the diffuser. This provides a self-locking system, and the diffuser can be secured with smaller and fewer bolts.

Another vertical hydrojet propulsion unit of the present invention comprises a housing rotatable in a horizontal plane; a water inlet arranged in the center of the bottom of the shell; a propeller disposed above the water inlet; a diffuser in communication with the water inlet; a pressure chamber in communication with the diffuser; and a water discharge port communicating with the pressure chamber and provided at the bottom of the casing, wherein the water discharge port is provided with a water discharge guide blade inclined at an angle such that the direction of water flow discharged from the water discharge port is as parallel as possible to the bottom of the casing.

As a result, the flow of water ejected from the drain port is achieved not directly downward but in the horizontal direction as much as possible, so that the efficiency of thrust generation can be improved.

In this case, the drain guide vane may be disposed to be inclined at an angle such that the water stream sprayed from the drain port is discharged in a direction opposite to the water inlet port. Thus, the water flow sprayed from the water outlet can be prevented from being quickly sucked into the water inlet, and the efficiency of generating the thrust is improved. Further, a water inlet guide vane may be provided on the water inlet port, the water inlet guide vane being inclined at an angle such that a direction of the sucked water flow is opposite to a direction of the water flow ejected from the water outlet port. Thus, the water flow sprayed from the water outlet can be prevented from being sucked, and the efficiency of thrust generation can be improved.

Further, the drain port may be arranged such that a center drain port symmetrical to a diametrical line passing through the center of the inlet port and/or side drain ports symmetrically arranged on both sides of the diametrical line, and the end surface on the inlet port side of the intermediate drain port is arranged to be perpendicular to the direction of the diametrical line. Thus, the angle of inclination of the side drain guide vane can be changed and adjusted. Thus, the left and right propelling forces are different in magnitude, and a moment is generated to compensate for a rotational moment caused by the rotational water flow generated by the rotation of the propeller. As a result, the power required to turn the housing to operate the motor can be reduced.

Furthermore, if the angle of inclination of the guide blades of the intermediate drain opening can be varied and adjusted, the load on the propeller can be adjusted. That is, if the area of the drain opening is increased, the load thereof is reduced. If the area is reduced, the load increases. The prime mover can be conveniently matched and adjusted at a constant rotating speed relative to the propeller by accurately adjusting the inclination angle.

FIG. 1 is a schematic cross-sectional view of a hydrajet propulsion unit WJ of the present invention;

FIGS. 2A and 2B are a schematic view and a perspective view, respectively, showing important parts of an example of a structure for improving the installability of a diffuser fixed to an inner ring by using a reaction force of a vane generated by a rotational force of the diffuser;

FIG. 3 is a schematic cross-sectional view of a vertical hydrojet propulsion unit;

FIG. 4 is a view showing the bottom of the housing of the vertical hydrajet propulsion unit;

FIG. 5A is a cross-sectional view of a drain opening portion with a stationary guide vane; FIG. 5B is a schematic view of an adjustable drain guide vane;

FIG. 6 is a cross-sectional view of a conventional vertical hydrajet propulsion unit;

fig. 7 is a plan view of a conventional vertical hydrojet propulsion unit as seen at the diffuser.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a schematic cross-sectional view of a hydrajet propulsion unit WJ of the present invention.

The hydrojet propulsion unit WJ is mounted on the hull 1. The hydrojet propulsion unit comprises: a platform 4 on which a vertical gear box 3 is mounted, a power transmission mechanism 2 being mounted at a central portion of the vertical gear box 3; an inner ring 5 extending below the central portion of the platform 4; a propeller shaft 7 vertically inserted into the inner ring 5, the lower end of the shaft being provided with a propeller 6; a diffuser 8 located downstream of the impeller 6 and fixed to the inner ring 5; and a housing 10 supported by the inner ring 5 and other components and driven to rotate by an operating motor 9.

The platform 4 is positioned on the opening 1c of the hull 1 and is mounted on the base plate 1a inside the hull 1. A drive shaft 11 (not shown) extending from the prime mover is inserted and supported in the gear case 3 vertically disposed at the central portion of the platform 4. A bevel gear 2a is mounted on top of the gear housing 3. The gear 2b is engaged with the bevel gear 2a to form the power transmission device 2. The propeller shaft 7 is vertically inserted into the cylindrical inner ring 5 below the gear 2b, and is supported by upper and lower bearings 7 a.

The inner ring 5 is connected to and in contact with the gear housing 3 and projects in a cylindrical manner downward thereof. A diffuser 8 and a propeller shaft seal 12, which are in sliding contact with the propeller shaft 7, are mounted on the flange portion 5a, and the flange portion 5a is fixed to the lower end of the inner ring 5 by a plurality of bolts 8 b. The inner ring 5 is mounted on the platform 4 and the platform 4 is fixed to the hull 1, together forming a fixed part. The diffuser 8 is fixed to the inner ring 5, likewise forming a non-rotating fixed part.

As described above, the seawater chamber 12a and the lubrication chamber 12b are separated from each other, and mutual entry and leakage of seawater and lubricating oil between the seawater chamber 12a and the lubrication chamber 12b are prevented due to the propeller shaft seal 12 installed between the diffuser 8 or the fixed portion of the inner ring 5 and the rotating propeller shaft 7.

Meanwhile, a cylindrical housing 10 is mounted on the opening portion 1C of the hull and is provided at the center thereof with an outer ring 13 concentric with the inner ring 5. The outer ring 13 is supported by and engages the inner ring 5 by a rotary bearing 14. The outer ring 13 is separate from the diffuser 8 and is independently rotatable with respect to the diffuser 8. In particular, the diffuser 8 of the fixed part and the housing 10 of the rotating part are in sliding contact and engaged by only one rotating seal 15, but are separate or independent from each other.

Likewise, the seawater chamber 12a and the lubrication chamber 12b are isolated from each other, and the seawater and the lubricating oil between the seawater chamber 12a and the lubrication chamber 12b are prevented from entering and leaking each other due to the rotary shaft seal 15 installed between the diffuser 8 or the fixed portion of the inner ring 5 and the housing 10. A seal 4a mounted between the housing 10 and the platform 4 also separates the seawater chamber 12a and the lubrication chamber 12b from each other.

An engaging gear 13a is mounted on an outer ring 13 of the housing 10. The meshing gear 13a meshes with a gear 9b, the gear 9b is mounted on a shaft 9a of the steering motor 9, and the steering motor 9 is mounted on the platform 4 so that the housing 10 can be driven by the steering motor to rotate independently.

The central bottom 10a of the housing 10 is provided with a water inlet 16, and the inner wall 10b of the housing 10 vertically surrounds the impeller 6. The above-mentioned diffuser 8 is disposed at the upper end of the inner wall 10b, but is separated therefrom. The diffuser 8 is provided therein with a water flow passage, which is pushed out by the propeller 6, flows, and is guided by the radial blades 8 a. As described above, the flow of water flowing out of the propeller 6 is changed into a rotating flow of water and then acts on the blades 8 a. However, since the diffuser 8 is fixed to the hull and is separated from the hull 10, the rotational moment generated by the reaction force acts on the hull without affecting the rotation of the hull 10. Only a small force is required to operate the motor 9 to rotate the housing 10 itself.

The water flowing out of the diffuser 8 enters a pressure chamber 17 of the casing 10 connected to the diffuser 8, and the water in the pressure chamber 17 is discharged from a water discharge port 18 having guide vanes 18a fitted to the bottom 10a of the casing, thereby generating a propelling force. By rotating the housing 10, the position of the drain port 18 can be freely changed within a range of 360 °.

Fig. 2A and 2B show an example of a structure that can improve the mountability of the diffuser fixed to the inner ring by using the reaction force of the vane generated by the rotational force of the diffuser.

Specifically, a tapered surface 19a is designed so that a rotational force Y caused by a reaction force of the water current acting on the diffuser 8 pushes a ring member 8c protruding in the diffuser 8 and a flange 5a at the lower end of the inner ring 5, on which the ring surface 8c is seated, at a joint surface 18 between the ring member 8c and the flange 5a and the tapered surface 19. In this way a self-locking system is achieved, as a result of which only few and very small connecting bolts are required for fixing the diffuser 8.

Another preferred example will be described in conjunction with fig. 3 to 5.

Fig. 3 is a schematic sectional view showing a vertical type hydrajet propulsion unit, and fig. 4 shows the bottom of the casing. The vertical hydrojet propulsion unit WJ is mounted at the bottom 21 of the vessel. The cylindrical housing 23 of the propulsion device is concentrically mounted within the circular opening portion 22 of the bottom 21. The housing 23 is secured to the vessel bottom 21 by a platform 24. That is, a rotary bearing 40 is provided to roll between the upper portion of the inner ring 34 and the outer ring 39 at the inner bottom end of the upper wall 23C of the housing 23. The housing 23 is capable of rotation and is supported by the hull wall as a unit. Thus, the hull 23 is mounted on the hull by means of the platform 24, ensuring rotation of the hull 23. A gear box 28 is disposed in the middle of the platform 24, and an input shaft 29 is inserted transversely into the gear box 28 and supported by bearings 30. A bevel gear 31 is provided at the top end of the input shaft 29. The upper part of the output shaft 32 has a bevel gear 33 which engages with the bevel gear 31 to form a bevel gear pair. The output shaft 32 extends vertically downward through a hole in the inner ring 34 to the lower portion of the gear case 28. A projection 35 is provided on the lower portion of the output shaft 32, and a propeller 36 is mounted on the projection. The output shaft 32 is rotatably supported by a bearing 32a between the output shaft 32 and the inner ring 34.

The housing 23 has a conical central wall 23a, the lower portion of which is recessed downwardly to surround the outer edge of the inner ring 34. The lower end of the central wall 23a extends up to the upper end of the projection 35. The central portion of the bottom 23e of the housing 33 is upwardly and outwardly angled from the narrow gap formed between the central portion and the top end of the impeller 36 to form an inner wall 23 b. The inner wall 23b flares upward and extends from the same location as the bottom of the conical central wall 23a and a defined distance therefrom to form a diffuser 37. A flow sheet 38 is provided on the diffuser 37 in the radial direction, i.e., between the central wall 23a and the upper portion of the inner wall 23 b.

A pinion 41a mounted on the platform 24 to operate the lower end of the shaft of the motor 41 is engaged with the outer ring 39. If the motor 41 is operated to drive the pinion 41a to rotate in a predetermined direction, the housing 23, which is integrated with the outer ring 39 engaged with the pinion 41a, rotates about the center of the output shaft 32. Therefore, the position of the drain opening 42, which will be described later, can be freely changed within a range of 360 °. Further, an annular projection 25 is provided on the upper wall 23c inside the cylindrical housing 23. A guide ring 26 projecting downwardly from the platform 24 is concentrically engaged with the outer circumference of the projection 25 by a seal 27.

A circular opening portion surrounded by the inner wall 23b below the impeller 36 forms a water inlet 43. The water inlet 43 is disposed in series with respect to the diffuser 37 and communicates with a pressure chamber 44 provided between the outer wall 23d and the inner wall 23b of the housing 23. A drain opening 42 (in fig. 3, an intermediate drain opening 45, which will be described later) is provided in the wall of the bottom portion, so that water ejected from the pressure chamber 44 is discharged from the drain opening 42. A plurality of arc-shaped drain guide vanes 42a are provided on the drain 42, and have an inclination angle such that the discharged water stream is ejected in a horizontal direction as much as possible or in a direction parallel to the bottom 23e of the housing 23 as much as possible. This is because the more water is ejected in the horizontal direction, the more effective the thrust is generated. Since the inlet port 43 and the drain port 42 are both provided on the bottom 23e of the housing 23, the plurality of suction guide vanes 43a of the inlet port 43 have an inclination angle opposite to that of the drain port guide vanes 42a, so that the water discharged from the drain port 42 is not sucked by the inlet port 43 quickly. According to the above description of the structure of the vertical type hydro-jet propulsion device WJ, the water flow is sucked from the water inlet 43 through the rotating propeller 36, as shown by the arrow in fig. 3, the pressure of the water in the propeller is increased, and the water is discharged from the diffuser into the pressure chamber 44. The pressure energy of the water in the pressure chamber 44 is converted into kinetic energy and the water is ejected from the water discharge port 42 to generate a desired thrust.

As shown in FIG. 4, the drain opening 42 includes a central drain opening 45 and side drain openings 46 around its periphery. The intermediate drain opening 45 is designed in a rectangular shape having a dimension in a tangential direction of the water inlet 43 larger than a diameter of the circular water inlet 43. It is preferable that the side end face 45a of the intermediate drain opening 45 opposed to the water inlet 43 is designed to be perpendicular to a diametrical line O passing through the center of the circular water inlet 43. The reason for this is that the water flow is fully utilized to form thrust, and the loss caused by the partial water flow flowing to the right lower side is avoided. The end surface may be arranged concentrically with the water inlet 43 as shown by the imaginary line 45B, so that the efficiency of the thrust by the water flow is not reduced too much. The side drain openings 46 have the same size and are symmetrical about the diametrical line O. Not only the drainage guide vane 42a but also the side drainage port 46 is provided at the intermediate drainage port 45. Fig. 5 shows a sectional view of the guide vane 42 a. The guide vane 42a installed at the side discharge opening 46 is inclined at an angle opposite to that of the inlet guide vane 43a to prevent the water flowing out of the discharge opening 42 from being rapidly sucked into the inlet 43.

As shown in fig. 5B, the drain guide vanes attached to the intermediate drain port 45 and the side drain port 46 are inclined at variable angles like the variable guide vanes 42B. That is, the center of each variable guide vane is rotatably supported, and an operating rod 49 extending from a link 48 of the driving cylinder 47 is connected to the upper end of the guide vane 42b through a connecting material 50, respectively. The variable guide vanes 42b can be adjusted to the desired angle of inclination by operating the actuating cylinder 47 to extend or retract the rod 48.

If the intermediate drain opening 45 has guide vanes with variable pitch, it can be used to adjust the drain opening to match the propeller when the prime mover connected to the input shaft is rotating normally at a certain speed. If the guide vanes of the side discharge openings 46 are variably pitched, it may be useful to vary the balance of the water flow rate discharged between the left and right discharge openings and thereby vary the flow forces to compensate for the imbalance in the rotational moments. This makes it possible to reduce the power for operating the motor.

Claims (5)

1. A vertical water jet propulsion unit comprising a housing rotatable by operation of an electric motor, a water stream flowing upwardly from the bottom of the housing by rotation of a propeller, the water stream being fed through a diffuser into a pressure chamber of the housing and discharged from a discharge port in the bottom of the housing, characterized in that an inner ring supported by a hull and having a propeller shaft inserted therein is provided in the upper part of the center of the housing; the diffuser is integral with or integrally mounted on the inner ring; characterised in that the housing is supported by the inner ring via a rotary bearing.

2. The vertical hydrojet propulsion unit of claim 1, wherein the lower end of the downwardly extending cylindrical inner ring connected to a gear box is within the housing; and a diffuser is installed at the lower end of the inner ring.

3. A vertical hydrojet propulsion unit according to claim 1 or 2, in which a propeller shaft seal is provided between the fixed part of the diffuser or inner ring and the rotating propeller shaft to separate the sea water part from the lubrication chamber.

4. A vertical hydrojet propulsion unit according to any one of claims 1 and 2, in which a rotary seal is provided between the stationary part of the diffuser or inner ring and the rotating casing to separate the sea water part from the lubrication chamber.

5. The vertical hydrojet propulsion device according to any one of claims 1 to 2, wherein the contact surface between the diffuser and the inner ring incorporated in the diffuser is designed as a conical surface, and the diffuser and the inner ring are pushed against each other by the rotational force caused by the reaction force of the water flow on the diffuser.