JPH0154239B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rudder structure equipped with blades that can promote energy saving and is advantageous in terms of strength.

In order to increase the effectiveness of the rudder in moving the ship straight or turning, it is advantageous to place the rudder in the wake of the propeller, where the flow velocity is high, and for this reason the rudder is usually placed behind the propeller. However, in addition to the above functions, the rudder also has the function of propelling the ship. That is, the rudder generates lift by receiving the wake of the propeller, and the propulsion direction component of this lift contributes to the propulsion of the ship.

In order to advantageously utilize the propulsion direction component of the lift generated by the wake of the propeller, the inventor of the present application has already proposed a method for disposing the propeller at the rear of the propeller, as shown in Utility Model Application No. 57-24509 (Utility Model Publication No. 61-27360). A rudder design in which blades that protrude laterally are attached to both sides of the rudder plate, and the installation height of the blades is positioned above the center of the propeller shaft, and a utility model registration filed on June 21, 1981. As shown in the application (Utility Model Publication No. 61-27838) (name of the invention: rudder with vanes), focusing on the longitudinal component of the propeller wake, we installed lateral side panels on both sides of the rudder plate placed behind the propeller. We devised a rudder in which a blade was attached to the vessel, and the port and starboard sides of the blade were twisted upside down. However, in these designs, it cannot be said that the propulsion direction component of the lift force is fully utilized for propulsion of the ship.

The present invention focuses on the attachment angle of the blades when viewed from the front, and has been made with the aim of making even more effective use of the propulsion direction component of the lift force generated by the wake of the propeller, and making it advantageous in terms of strength. .

First, the concept of the present invention will be explained.

In the wake of the propeller, due to the induced speed of the propeller, as shown in Fig. 1, there is a spiral flow in the same direction as the rotational direction i of the propeller 1, whose rotational direction components are rotational flows a to h with a speed υ〓. It is formed.

Let's take as an example the case where the blades are attached to both sides of the rudder (the concept is the same even if they are attached to both sides of the rudder support). Consider the case where it is mounted a required distance above the center.

As shown in FIG. 2, when the blade 2 is installed horizontally to the rudder 3 when viewed from the front and a vertical distance H above the propeller shaft center P, the first
The rotational flow υ of the propeller 1 shown in the figure flows obliquely into the blades 2. At this time, the vertical component of υ〓 is an effective component that generates lift on the blade 2, but the horizontal component (horizontal component from the base end of the blade to the tip) generates lift force. (Details will be explained later).

In order to more effectively recover the energy of the rotational flow υ〓 discarded backward by the propeller 1, it is possible to make the rotational flow υ〓 and the blades 2 perpendicular to each other. The generation of components will disappear. In other words, in order to use all the components of the rotating flow υ〓 to generate lift of the blade 2, as shown in Fig. 3,
The blade 2 may be sloped upward at an angle β with respect to the horizontal when viewed from the front. The angle β is
It is determined by the vertical distance H from the propeller shaft center P to the base end of the blade 2. Also, the optimal vertical distance H is
As explained in Utility Model Application No. 57-24509, we compared and examined the magnitude of the rotational flow caused by the propeller wake, which is under the control of the ship's wake flowing into the propeller surface, and the magnitude of the blade area, and determined the axial direction of the lift force. The position that maximizes the thrust component is selected. This position is not uniformly determined because the hull wake distribution differs depending on the ship type, but it is thought to be approximately above the propeller axis center P and 0.2 to 0.4 times the propeller radius. Below this position, the rotational flow caused by the propeller wake is relatively weak, and even if blades are attached here, energy cannot be recovered effectively. In addition, in FIG. 2 and FIG. 3, X is a propeller circle.

Figure 4 is an enlarged view of the blade in Figure 2, and Figure 5 is an enlarged view of the blade in Figure 3.
The propeller rotational flow υ〓 flowing obliquely into the blade 2 is
The blade 2 is shown vector-separated into a vertical component υ _V and a horizontal component υ _H. Then, from the geometric calculation of vectors, the following relationships hold: υ _V = υ〓cosβ υ _H = υ〓sinβ. However, β in Fig. 4 is the angle between the rotating flow υ〓 and the direction perpendicular to the blade 2,
This is equal to the angle β shown in FIGS. 2 and 5.

In addition, Fig. 6 and Fig. 7 correspond to Fig. 2 and Fig. 4, respectively.
FIG. 6 is a side sectional view of the blade 2 at a typical position shown in FIGS. 3 and 5, and FIG.
FIG. 7 is a side sectional view when the blade 2 is attached with an upward slope when viewed from the front.

In FIG. 6 and FIG. 7, υ _x is the axial direction (front-back direction) component of the propeller wake. Also, the vertical component υ _V in Figure 6 is the vertical component υ _V in Figure 4.
And, the rotational flow υ〓 in FIG. 7 is the same as the rotational flow υ〓 in FIG. 5, respectively. Therefore, in FIG. 6, the diagonal flow υ ₁ , which is a vector combination of the two flows υ _x and υ _V , flows into the blade 2. In addition, in FIG. 7, a diagonal flow υ ₂ which is a vector combination of υ _x and υ〓 flows into the blade 2. From this geometric relationship, υ ₁ =√ _x ² + _V ² =√ _x ² +〓 ^{2 2} υ ₂ =√ _x ² +〓 ² holds, and since cos ² β＜1, υ ₂ ＞υ _1. Become.

On the other hand, the blade 2 is installed so as to have the optimum angle of attack α with respect to the diagonal flow υ ₁ or υ ₂ so that the induced drag generated in the blade 2 is minimized. At this time, the lift force generated in the blade 2 is proportional to the square of the inflow velocity. As mentioned above, since υ ₂ > υ ₁ , the lift force L ₂ in FIG. 7 is larger than the lift force L ₁ in FIG. 3. Furthermore, the diagonal flow υ ₂ has a larger inflow angle than the diagonal flow υ ₁ . According to the lift principle, lift is generated at right angles to the diagonal flow υ ₁ or υ ₂ flowing into the blade 2. Therefore, the lift force _L2 is more inclined with respect to the vertical direction than the lift force _L1 .

Since L ₂ > L ₁ and the slope of L ₂ > the slope of L ₁ , the longitudinal component of the lift force, that is, the blade 2
The thrust force generated in Fig. 7 is larger. Therefore, when the blade 2 is installed above the propeller shaft center P, it is better to tilt the blade 2 upward at the angle β when viewed from the front, so that the longitudinal component of lift force, that is, the thrust force generated on the blade 2, is better. (thrust) increases.

Next, a case will be considered in which the blades attached to the rudder or the rudder support move up and down as the ship shakes (particularly rolls) in waves.
When the agitation becomes severe, the feathers fly out of the water into the air and then re-enter the water, repeating this motion. When the blade enters the water from the air, that is, when it lands on the wave surface, a large impact pressure is applied to the blade. If this impact pressure can be alleviated even a little, the design of the blade will be advantageous in terms of its strength, and it will be possible to design a blade with a lighter structure.

It is generally known that an acute-angled wedge can reduce the impact pressure of a wedge better than an obtuse-angled wedge. For example, the famous von-Karman equation for wedge impact pressure is expressed as follows:

p=π/tanβ'・1/2ρV ^2Where , p: Impact pressure β': Angle of the wedge hypotenuse with respect to the horizontal plane V: Water entry velocity ρ: Water density π: Pi In the above equation, the angle β' is also It can be seen that as the value increases, the acute wedge and the impact pressure p become smaller. This also applies to the blades of the present invention. That is, the horizontally mounted Figure 2 (Figure 4)
Figure 3 (Figure 5, Figure 7) has an angle of inclination of β when viewed from the front than the installation state shown in Figures 5 and 7.
The impact pressure applied to the blade is smaller in the mounting condition shown in Figure).

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 8 shows an embodiment of the present invention, in which 1 is a propeller, 2 is a blade fixed to the side of the rudder 3, and the base end of the blade 2 is located above the propeller shaft center P by a vertical distance H. It is located in Figure 3 and Figure 5 when viewed from the front.
As shown in the figure, it has an upward slope from the proximal end toward the distal end.

With such a configuration, as explained in the concept section, the longitudinal component of lift force, that is,
The thrust force generated in the blades 2 becomes larger, and the propulsion direction component of the lift force generated by the propeller wake is used more effectively, which is advantageous in terms of the strength of the blades 2.

FIG. 9 shows another embodiment of the present invention, and the difference from the previous embodiment is that in the previous embodiment, the blades are attached to the side plates of the rudder, whereas in this embodiment, the rudder support member 4
The reason is that the blade 2 is fixed to the side. The base end of the blade 2 is located above the propeller axis center P by a vertical distance H, and when viewed from the front, as shown in Figures 3 and 5, it has an upward slope from the base end to the tip end. , is the same as the blade in Fig. 8. In this way, even if the blade 2 is attached to the side part of the rudder support member 4, the eighth
The same effects as in the case shown in the figure can be achieved.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

According to the rudder structure in which the blades of the present invention are attached, the upwardly sloping blades are positioned such that the base end side is low and the tip side is high, and the base end side is above the center of the propeller axis and at a position 0.2 to 0.4 times the propeller radius. Because it is fixed to both sides of the members that make up the rudder, it is possible to more effectively convert the energy of the rotational flow thrown away by the propeller into thrust force. Therefore, if the blades are simply installed horizontally, As shown in Japanese Patent No. 62099, energy saving is further promoted compared to the case where blades are tilted upward and blades tilted downward around the propeller shaft.
In addition, since the impact pressure can be alleviated, it is effective in terms of strength and can produce various excellent effects such as being able to provide a lighter structure of the blade.

[Brief explanation of drawings]

Figure 1 is an illustration of the propeller wake generated by the propeller only, Figure 2 is an illustration of the case where the blades are installed horizontally on the rudder side, and Figure 3 is an illustration of the blades installed at an angle on the rudder side. Figure 4 is an enlarged illustration of the blade part in Figure 2, Figure 5 is an enlarged illustration of the blade part in Figure 3, and Figure 6 is an illustration of the blade part in Figure 2 and Figure 4. A side sectional view at a representative position of the blade shown in Fig. 7.
The figure is a side sectional view of the blade at a typical position shown in FIGS. 3 and 5, and FIG. 8 is an explanatory diagram of an embodiment of the present invention.
FIG. 9 is an explanatory diagram of another embodiment of the present invention. In the figure, 1 is a propeller, 2 is a blade, 3 is a rudder, and 4 is a rudder support member.

Claims (1)

[Claims] 1. On both sides of the member constituting the rudder placed behind the propeller, install upwardly inclined blades with the base end side low and the tip side high. A rudder structure equipped with vanes that are fixed in a double position.