JPS6211720B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a rudder for a ship.

In the case of a conventional ship equipped with a normal rudder, the rudder acts as nothing more than resistance when the ship is moving straight, and the energy of the rotational flow behind the propeller is lost, which is one of the reasons for the reduction in propulsion efficiency. In addition, in the case of conventional regular rudders, in order to improve turning performance, it is necessary to increase the ratio of the rudder's length to height (aspect ratio) or to increase the rudder area. On LPG ships with a lot of water, the center of buoyancy is at the rear and the water is shallow, so there is a problem that it is difficult to install a large rudder that satisfies these conditions.

An object of the present invention is to provide an efficient rudder that can reuse the energy of the rotational flow downstream of a propeller as propulsion force for a ship, can be constructed in a small size, and has good turning performance.

The rudder of a ship according to the present invention has a rudder arranged approximately vertically above and below the propeller center line behind the propeller.
It consists of a pair of cylindrical or truncated conical rotors, and these rotors can rotate independently around their respective central axes.

As shown in Figures 1 and 2, when the cylindrical bodies 1 and 2 are placed in constant fluid flows V1 and V2 and rotated around the central axis, the blades are inserted into the flow. Lifting forces L1 and L2 are generated in the same way as when it is placed. This effect is called the Magnus effect, and experiments have shown that the lift coefficient of a rotating cylindrical body is lower than that of a normal wing.
It is known that it can be made about 10 times larger. By changing the rotation direction and rotation speed of the rotating cylindrical body, the forces F1 and F2 acting on the cylindrical body are
The direction and magnitude of (the resultant force of lift forces L1, L2 and drag forces R1, R2) can be changed. The same applies when a truncated cone is used instead of a cylinder.

When a ship's propeller rotates clockwise when viewed from the rear, the propeller wake becomes a rotational flow, and above the propeller center line, it flows diagonally from the left corner to the upper rotor, and below this, it flows diagonally downward from the right corner. flows into the side rotor. Therefore, by rotating the upper rotor clockwise when viewed from above and rotating the lower rotor counterclockwise when viewed from above at approximately the same speed, the vessel is made to proceed straight, as explained below. At the same time, it is possible to generate propulsive force in these rotors. That is,
Similar to the cylindrical body 1 in Fig. 1, the upper rotor, which rotates clockwise when viewed from above, is subjected to a diagonally forward force F1 due to the oblique flow V1 from the left side, and as shown in Fig. 2. Similar to the cylindrical body 2, a diagonally left forward force F2 acts on the lower rotor, which rotates counterclockwise when viewed from above, due to an oblique flow V2 from the right corner. When the rotational speeds of the upper and lower rotors are approximately equal, the force F acting on the upper and lower rotors is
1, F2 in the left-right direction component forces C11, C12 are balanced, so the ship moves straight, and the components C21, C of these forces F1, F2 in the ship's traveling direction (rightward in the drawing)
22 both act as a propulsive force. In addition, by rotating the upper and lower rotors in opposite directions at different speeds or in the same direction,
The ship can be turned as described next. That is, as is clear from FIGS. 1 and 2, when the upper and lower rotors rotate in opposite directions, the directions of the horizontal components C11 and C12 of the forces F1 and F2 that act on them are opposite. However, when the rotational speeds of the upper and lower rotors are different, a difference occurs in the magnitude of these component forces C11 and C12, and a turning moment corresponding to this difference is generated in the ship. In addition, when the upper and lower rotors rotate in the same direction, the directions of the horizontal component forces C11 and C12 of the forces F1 and F2 that act on them are the same, so the ship has a large force corresponding to the sum of these forces. A turning moment is generated.

As mentioned above, according to the ship rudder of this invention,
By appropriately adjusting the rotational direction and rotational speed of the upper and lower rotors, it is possible to make the ship go straight or turn in the same way as with a normal rudder. Also,
When the ship is moving straight, the upper and lower rotors are rotated in opposite directions at approximately the same speed, so that propulsive force can be obtained using the rotational flow behind the propeller, improving the propulsion efficiency of the ship. Further, the rudder according to the present invention is composed of a pair of upper and lower rotors, and the magnitude of the turning moment can be changed by adjusting the rotation direction and rotation speed of these rotors, so it can be constructed compactly and has excellent turning performance. Even when sailing at low speeds, which is a problem with conventional rudders, sufficient turning performance can be obtained by rotating the upper and lower rotors in the same direction at high speeds. Further, a cylindrical or truncated conical rotor is easy to manufacture and can be driven by a motor or the like, so the structure is simpler and cheaper than a typical steering device.

An embodiment of the present invention will be described below with reference to FIG.

FIG. 3 shows the stern part of the ship, where a pair of cylindrical rotors 11,
12 are arranged almost vertically. Vertical drive shaft 1
The upper and lower ends of the shaft 13 are rotatably supported by the stern protrusion 14 and the shoe piece 15.
The center of the lower rotor 12 is fixed to the lower part of the rotor. Further, a vertical hollow drive shaft 16 coaxial with this shaft 13 is rotatably supported on the portion of the drive shaft 13 excluding the lower and upper ends and on the stern protrusion 14. rotor 11
The center of is fixed. At the upper ends of these drive shafts 13 and 16 located in the stern protrusion 14, there are gears 1 connected to two motors (not shown), respectively.
7, 18 are fixed, and the upper and lower rotors 11,
12 can rotate independently about their respective central axes. In addition, each rotor 11,
The rotation direction and rotation speed of 12 can be changed arbitrarily.

When the ship is to go straight, the upper rotor 11
is rotated clockwise when viewed from above, and the lower rotor 12 is rotated counterclockwise when viewed from above at approximately the same speed. In this way, as described above, no turning moment is generated in the ship, and the rotational flow of the propeller wakes the upper and lower rotors 11,
Propulsive force is generated at 12. Note that the propeller wake is affected by the shape of the ship at the stern, and the inflow angles to the upper and lower rotors 11 and 12 are not necessarily equal, so the left-right component of the force acting on the upper and lower rotors 11 and 12 is The rotational speeds of the upper and lower rotors are not necessarily the same when the ship is moved straight by balancing them.

When turning the ship, the upper and lower rotors 1
1 and 12 may be rotated in opposite directions at different speeds or in the same direction. In this way, as described above, a turning moment is generated in the vessel. In this case, the upper and lower rotors 11,
12 do not necessarily need to be rotated in the same direction, but as mentioned above, if they are rotated in the same direction, a very large turning moment can be generated.

The rotors 11, 12 may have a truncated cone shape, and the configuration for supporting and rotating them is as follows:
The present invention is not limited to the above embodiments, and may be modified as appropriate.

FIG. 4 shows an embodiment different from the above, in which a vertical plate-like member 19 fixed to the hull is arranged immediately after the upper and lower rotors 11, 12 similar to the above, and the whole has an airfoil shape. FIG. 5 shows a further different embodiment, in which a member 20 similar to the above is placed immediately after the upper and lower rotors 11, 12, and a vertical member 20 fixed to the hull is placed immediately in front of the rotors 11, 12. Column-shaped members 21 are arranged, and the whole has an airfoil shape. In the case of Figures 4 and 5,
Not only will the resistance to the wake of the propeller be reduced, but it can also be expected to increase the propulsive force due to lift.

[Brief explanation of the drawing]

1 and 2 are diagrams explaining the principle of this invention, FIG. 3 is a partially cutaway side view of the stern portion showing an embodiment of the invention, and FIGS. FIG. 3 is a plan view of a rudder showing two embodiments. 10...Propeller, 11,12...Rotor.

Claims (1)

[Claims] 1 Consists of a pair of cylindrical or truncated conical rotors 11 and 12 arranged substantially vertically above and below the propeller center line at the rear of the propeller 10, and these rotors 11 and 12 are arranged separately around their respective central axes. A ship's rudder that is capable of rotating.