JPS6216879B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for improving the propulsion performance of a ship.

Figure 1 shows the stern section of a normal one-shaft, one-rudder boat, with several fins installed in front of the propeller to give the flow flowing into the propeller a rotational flow in the opposite direction to the rotation of the propeller. This shows a conventional ship propulsion performance improvement device designed to improve propulsion efficiency by canceling rear rotational flow, and the fins mentioned above are generally called reaction fins.

In the conventional ship propulsion performance improvement device shown in FIG. 1, 1 is the hull, 1a is the bottom of the ship, 2 is the propeller, 3 is the propeller boss, 4 is the rudder, 5 is the upper rudder support member, 6 is the rudder stem, 7 8 is a propeller cap, and 9 is a propeller shaft.The rear end of the coaxial shaft 9 is connected to the propeller 2, and the front end of the coaxial shaft 9 is connected to a motor (not shown). Reference numeral 10 denotes a stern boss (hereinafter referred to as the boss). The boss 10 is rotatably mounted around the propeller shaft 9, and the front end of the boss 10 is connected to the stern frame 11.
a, 11b. 11a is an upper stern frame, 11b is a lower stern frame,
12a, 12b, 12c, 12d, 12e, 12
f is a fin, 13 is a load water line, and 14 is a propeller shaft center line.

Various shapes of reaction fins have already been developed to improve ship propulsion performance. The inventors also conducted experiments to improve propulsion efficiency and developed a ship propulsion performance improving device as shown in FIGS. 2 and 3, and have already filed an application.

FIG. 2 is a sectional view corresponding to the cross section shown in FIG. 1, and is a sectional view of a marine vessel propulsion performance improvement device for which the inventors have already filed an application, and FIG. 3 is a side view thereof from the starboard side.

In FIGS. 2 and 3, parts equivalent to those in FIG. 1 are given the same reference numerals. Further, 12a', 12b', 12d', and 12e' are attached to the boss 10 radially. The port side fins 12a', 12b' are only inclined downward at the rear edge with respect to the propeller shaft center line 14, and are not twisted. On the other hand, the fins 12d' and 12e' on the starboard side are twisted upward at the rear edge so that the mounting angle is larger at the tip than at the mounting root of the boss 10. Note that the installation angle is the angle between the chord of the fin and the propeller axis. 15a, 15b, 15c, 15d, 15
e and 15f are reinforcing materials, and the same reinforcing materials 15a and 15
b, 15c, 15d, 15e, 15f are fins 1
2a', 12b', 12d', and 12e' are fixed near the center, and are connected to the adjacent fins and the upper and lower stern frames 11a, 11b, and are reinforced to prevent vibration of the reaction fins. It is.

This prior application example (Japanese Unexamined Patent Application Publication No. 1983-1989) is structured in this way.
In the ship propulsion performance improvement device of 492), a propeller shaft 9 is rotated by a prime mover (not shown) inside the ship, and when the propeller shaft 9 rotates, the propeller 2 turns to the right, the ship 1 travels. At that time, the flow of water in the stern section of the fins 12a', 12b', 12
The rotation direction of the propeller 2 is changed by d' and 12e', that is, counterclockwise, and the flow flows into the propeller 2. Therefore, the rotational flow generated behind propeller 2 (clockwise, same as propeller 2) is reduced,
Energy loss is reduced accordingly and propulsion efficiency is improved. At that time, in particular, the reinforcing materials 15b, 1
Due to the action of 5e, the resistance of the hull increases, and the propulsion performance decreases by that amount.

In other words, it was found that the resistance of the reinforcing material intersecting the water line passing through the propeller shaft centerline 14 was extremely large. Therefore, the resistance of the hull increases, and the propulsion performance decreases by that amount.

The present invention has been made based on the above findings. That is, in front of the screw propeller at the stern, a plurality of fins are formed to protrude radially from a boss surrounding the propeller shaft and are formed so as to convert the direction of the flow flowing into the propeller into a direction opposite to the rotating direction of the propeller. In the case of a reaction fin equipped with a reaction fin, when the blade of the propeller rotating in the direction of moving the ship forward moves downward, the mounting angle of the fin is upward from the mounting part of the boss to the tip of the fin. On the side where the wing moves upward, the mounting angle of the fin is made the same from the mounting part of the boss to the tip of the fin in the downward direction of the trailing edge, and the fin and stern are twisted. It is characterized in that the reinforcing material that is fixed to the frame is arranged so as not to intersect the water line passing through the center line of the propeller shaft, and its purpose is to eliminate the drawbacks of the conventional device, Furthermore, the present invention provides a ship propulsion performance improvement device that can improve propulsion efficiency.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the embodiment illustrated in FIGS. 4 and 5. In FIGS. 4 and 5, the same reference numerals are given to the same parts as those in FIGS. 1 to 3. Further, this embodiment also shows the case where the propeller rotates clockwise, and vice versa when the propeller rotates counterclockwise.

FIG. 4 is a sectional view of this embodiment showing the cross section shown in FIG. 5, and FIG. 5 is a side view thereof from the starboard side.

In FIGS. 4 and 5, the fins 12a',
12b', 12d', and 12e' are attached to the boss 10 radially. Port side fin 12a', 12
b' has the same mounting angle from the mounting root of the boss 10 to the tip of the fin, and is merely inclined downward at the trailing edge with respect to the propeller shaft centerline 14, and is not twisted. On the other hand, the starboard side fin 12d', 1
The mounting angle of 2e' is twisted upward at the rear edge so that the tip is larger than the mounting root of the boss 10, and the port side fins 12a', 12b' and the starboard side fin 12
Both fins d' and 12e' are the same as the fins shown in FIGS. 2 and 3.

Further, a reinforcing material 15 is provided between the center portions of the upper fins 12a' and 12e' and the upper stern frame 11a.
a, 15f are installed, and the lower fins 12b', 1
Reinforcing members 15c and 15d are installed between the center portion of 2d' and the lower stern frame 11b. The reinforcing material 15b intersects with the water line plane passing through the propeller shaft centerline 14 illustrated in FIGS. 2 and 3,
15e is not provided. In addition, the reinforcing material 15
a, 15c, 15d, and 15f may be provided not only at the center of the fin but also at the tip of the fin.

In this embodiment configured in this manner, the propeller shaft 9 is rotated by a prime mover (not shown) inside the ship, and when the propeller 2 rotates to the right due to the rotation of the propeller shaft 9, the ship body 1 moves forward. At that time, the flow of water in the stern section is caused by the fins 12a', 12b', 12d',
12e', the air is turned counterclockwise, which is opposite to the direction of rotation of the propeller, and flows into the propeller 2. Therefore, the rotational flow generated behind the propeller 2 in the same direction as the rotation (clockwise) of the propeller 2 is reduced, energy loss is reduced by that much, and the propulsion performance is improved.

At that time, since there is no reinforcing material that intersects with the water line passing through the propeller shaft center line 14, as shown in FIG. 6, reinforcing materials 15b and 15e are attached as shown in FIG. The resistance of the hull 1 is reduced compared to the ship propulsion performance improvement device. Figure 6 shows
This is a curve that represents the drag coefficient of the hull based on the Froude number. Curve A in the figure is the reinforcing material 15b of the earlier application,
Curve B is the measurement result when the reinforcing material 15e of this embodiment is installed, and the curve B is the measurement result when the reinforcing material 15b and 15e of this embodiment are not installed.

In addition, in this example, the reinforcing material is only fixed between the fins and the stand frame, but the number of fins is increased, the reinforcing material is fixed between the fins, and the space between the fins and the stand frame is fixed. Even if the propeller is stuck, a similar effect will occur if no reinforcing material is provided that intersects the water line passing through the propeller shaft centerline 14.

As detailed above in the above embodiments,
The present invention provides a plurality of projecting radial parts in front of a screw propeller at the stern of the ship, projecting radially from a boss surrounding the propeller shaft, and formed to convert the direction of the flow flowing into the propeller into a direction opposite to the rotating direction of the propeller. In a reaction fin equipped with a fin, on the side where the blade of the propeller rotating in the direction of moving the ship forward moves downward, the mounting angle of the fin with respect to the center line of the propeller shaft should be adjusted so that the mounting angle of the fin with respect to the center line of the propeller shaft is adjusted upward of the trailing edge of the boss. Twist the fin so that it becomes larger toward the tip of the fin, and on the side where the blade moves upward, adjust the mounting angle of the fin with respect to the center line of the propeller shaft downward from the trailing edge to the mounting part of the boss. Improved ship propulsion performance by making the fins uniform from the fins to the tips of the fins, and arranging reinforcing materials between the fins and between the fins and the stern frame so as not to intersect the water line passing through the center line of the propeller shaft. Since this is a device, the resistance of the ship body is reduced and the propulsion efficiency is increased compared to the ship propulsion performance improving device of the prior application which has a reinforcing material that intersects with the water line passing through the center line of the propeller shaft.

[Brief explanation of the drawing]

Fig. 1 is a side view of a marine propulsion performance improving device showing a conventional example, Fig. 2 is a marine propulsion performance improvement device showing an example of a prior application, Fig. 3 is a side view from the starboard side, and Fig. 4 is a side view of the marine propulsion performance improving device according to the present invention. A sectional view of one such embodiment, FIG. 5 is a side view from the starboard side, and FIG. 6 is a curve representing the drag coefficient of the hull based on the Froude number. DESCRIPTION OF SYMBOLS 1... Hull, 2... Propeller, 4... Rudder, 9... Propeller shaft, 10... Boss, 11a... Upper stern frame, 11b... Lower stern frame, 12a', 1
2b', 12d', 12e'...Fin, 14...Line parallel to the propeller axis, 15a, 15c, 15d, 15f
...Reinforcement material.

Claims (1)

[Claims] 1. In front of the screw propeller at the stern, a plurality of fins protrude radially from a boss surrounding the propeller shaft and are formed so as to convert the direction of the flow flowing into the propeller into a direction opposite to the rotational direction of the propeller. In the case of a reaction fin equipped with a reaction fin, on the side where the blade of the propeller rotating in the direction of forward movement of the ship moves downward, the mounting angle of the fin with respect to the center line of the propeller shaft is set upward at the rear edge of the mounting part of the boss. From there, twist the fin so that it becomes larger toward the tip of the fin, and on the side where the blade moves upward, adjust the mounting angle of the fin with respect to the center line of the propeller shaft from the mounting part of the boss to the fin in a downward direction from the trailing edge. A device for improving marine propulsion performance, characterized in that the fins are the same up to the tip of the fins, and a reinforcing material for fixing between the fins and the stern frame is arranged so as not to intersect with a water line passing through the center line of the propeller shaft.