JPS60183293A - Vibration damping type fin structure for ship - Google Patents

Abstract

PURPOSE:To make it possible to restrain an airfoil-like rectifier fin projected from the shell plating of a hull, from vibrating while a high propelling efficiency is sustained, by forming several vibration damping pores in the tip end section of the airfoil-like fin, which pierce therethrough and extend to the lower surface of the fin. CONSTITUTION:Several pores are formed in the tip end section of an airfoil-like fin 2 attached to a hull 1, for previously twisting a stream flowing into a screw propeller at the stern of the hull, or for rectifying a stream along the hull, the pores piercing through the fin and extending to the lower surface of the fin. Accordingly, upon vibration of tip end of the fin 2 the fluid flowing around the fin generates tiny vortices at the inlet and outlet of the pores 4 when it passes through the pores 4, and therefore, the damping coefficient of the fin 2 may be increased due to action of the viscosity of fluid within the pores. It is noted that the pores 4 are formed in several number in the part of the fin 2 where the vibration amplitude of the fin may be as large as possible while the air-foil efficiency is not substantially deteriorated.

Description

【発明の詳細な説明】 本発明は、船尾のスクリュープロペラへ流入する流れに
予めひねセ）を与えたり、あるいは船体に沿う流れの整
流を行なったりするために船体外面に突設されＩこフィ
ンの構造に関し、特に防振式のフィン構造に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention provides an I-shaped fin which is protruded from the outer surface of the ship in order to pre-tension the flow flowing into the stern screw propeller or to straighten the flow along the ship. The present invention relates to a vibration-proof fin structure.

第１〜３図は従来のフィン構造の４ａ要を示１もので、
１１１’Ｓｉ図はフィンをそなえた船尾部の側面図、第
２図は第１図のＩＩ　−ＩＩ矢矢視大火断面図第３図は
第２図の■−１１矢視拡に断面図である。Figures 1 to 3 show the main points of 4a of the conventional fin structure.
Figure 111'Si is a side view of the stern section with fins, and Figure 2 is a cross-sectional view of the conflagration taken along the II-II arrows in Figure 1. Figure 3 is an enlarged cross-sectional view taken along the ■-11 arrows in Figure 2. be.

船体１の船尾部外面に取すイ１けられたフィン２は、プ
ロペラ３に流れ込む流体を整流して、推進効率の向」二
をはかるものであり、したがってフィン２はなるべく薄
く細く形成されており、その長さもプロペラ３の直径を
超すものかよいとされているが、そうすると当然の結果
としてフィンの剛性の低下を招くことになるため、推進
効率の向上とフィン２の剛性の向上とは相反することに
なる。特にこのフィン２は、起振源としてのプロペラ３
や図示しない主機に近いところに設けられるため、振動
に対する配慮が重要となる。フィン２の固有振動数か起
振源の固有振動数と一致すると、フィン２１こ大きな振
動が発生するので好ましくないか、起振源との同調を完
全に防止するためには、フィン２を剛性の大きなものと
しなければならず、そうすると」二連したように推進効
率が低下してしまうという問題点かある。The fins 2 installed on the outer surface of the stern part of the hull 1 rectify the fluid flowing into the propeller 3 to improve the propulsion efficiency, so the fins 2 are formed as thin and narrow as possible. It is said that the length of the fins should exceed the diameter of the propeller 3, but this naturally results in a decrease in the rigidity of the fins, so improving propulsion efficiency and improving the rigidity of the fins 2 are contradictory. I will do it. In particular, this fin 2 is used as a propeller 3 as an excitation source.
Since it is installed near the main engine (not shown), it is important to take vibration into consideration. If the natural frequency of the fin 2 matches the natural frequency of the excitation source, it is undesirable because large vibrations will occur in the fin 21, or in order to completely prevent synchronization with the excitation source, the fin 2 should be made rigid. The problem would be that the propulsion efficiency would be reduced in a two-pronged manner.

本発明は、このような問題点を解決しようとするもので
、高い推進効率を維持しなが呟フィンの振動を十分に抑
制で外るようにした、舶用防振式フィン構造を提供する
ことを目的とする。The present invention aims to solve these problems, and provides a vibration-isolating fin structure for ships that sufficiently suppresses vibrations of the fins while maintaining high propulsion efficiency. With the goal.

このため、本発明の舶用防振式フィン構造は、船体外面
に突設された翼状フィンの先端部に、翼上下面に貫通す
る多数の防振用小孔か形成されたことを特徴としている
。Therefore, the marine vibration-isolating fin structure of the present invention is characterized in that a large number of small vibration-isolating holes penetrating the upper and lower surfaces of the wing are formed at the tip of the wing-like fin protruding from the outer surface of the hull. .

以下、図面により本発明の実施例について説明すると、
第４図は本発明の一実施例としての舶用防振式フィン構
造をそなえた船舶の船尾部の概要を示す斜視図、第５図
は第４図の＼ｌ−■矢視断面図である。Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
FIG. 4 is a perspective view showing the outline of the stern of a ship equipped with a marine anti-vibration fin structure as an embodiment of the present invention, and FIG. 5 is a sectional view taken along the \l-■ arrow in FIG. .

一般に、フィン２が流木中で共振し振動するときの先端
の振幅は、次式で゛表わされる。Generally, the amplitude of the tip of the fin 2 when it resonates and vibrates in the driftwood is expressed by the following equation.

と ただし　η＝フィン先端の振幅 δ＝滅哀率 ｗ　＝　４辰動有効重敵 ω＝２π［（［は固有振動数） Ｆ−有効起振力 」一式から明らかなように、フィン２の先端の振幅を抑
制するためには、減衰率δを増加さぜることが有効であ
ることがわかる。As is clear from the set of η = amplitude of the fin tip δ = extinction rate w = 4 effective heavy enemy ω = 2π [([ is the natural frequency) F - effective excitation force], the tip of the fin 2 It can be seen that increasing the attenuation rate δ is effective in suppressing the amplitude of .

そこで、本発明のフィン構造では、この減衰率を増加さ
せるため、第４，５図に示すように、船体に取付けられ
た翼状フィン２の先端部に、翼上下面に貫通する多数の
防振用小孔４が形成されるのである。Therefore, in the fin structure of the present invention, in order to increase this attenuation rate, as shown in Figs. A small hole 4 is formed.

本発明の舶用防振式フィン構造は−Ｌ述のように構成さ
れているので、フィン２の先端が振動して、その周囲の
流木か小孔４を通過する際に、小孔４の出入口では小さ
な渦を発生することにより、小孔４内では粘性の作用に
よって、フィン２の減衰率を増加させることができる。Since the marine anti-vibration type fin structure of the present invention is configured as described in -L, when the tip of the fin 2 vibrates and passes through the surrounding driftwood or the small hole 4, By generating a small vortex, the damping rate of the fin 2 can be increased by the action of viscosity within the small hole 4.

なお、小孔４の位置は、なるべく振幅の大きい位置に多
数設けるのか゛よく、したがって、フィン２の先端部に
おいて翼効率を損ねない程度にできるだけ多数の小孔４
を設けるようにする。It is preferable to provide a large number of small holes 4 at positions where the amplitude is as large as possible. Therefore, it is preferable to provide as many small holes 4 as possible at the tip of the fin 2 without impairing blade efficiency.
should be established.

以」二詳述したように、本発明の舶用防振式フィン構造
によれは、船体外面に突設された翼状フィンの先端部に
、翼上下面に貫通する多数の防振用小孔が形成されると
いう極めて簡素な構成で、推進効率の向上をはかりなが
ら、フィンの振動を十分に抑制する効果が得られるので
ある。As described in detail below, the marine vibration-isolating fin structure of the present invention has a large number of small vibration-isolating holes penetrating the upper and lower surfaces of the wing at the tip of the wing-like fin protruding from the outer surface of the hull. With this extremely simple configuration, it is possible to sufficiently suppress vibrations of the fins while improving propulsion efficiency.

【図面の簡単な説明】[Brief explanation of the drawing]

第１〜３図は従来のフィン構造の概要を示すもので、第
１図はフィンをそなえた船尾部の側面図、第２図は第１
図のｎ　−ＩＩ矢視拡大断面図、第３図は第２図の■−
ｍ矢視拡大断面図であり、第４図は本発明の一実施例と
しての舶用防振式フィン構造をそなえた船舶の船尾部の
概要を示す斜視図、第５図は第１１図の＼′−＼゛矢視
断面図である。 ］・・船（Ｌ　２・・フィン、３・・プロペラ、４・・
小孔。 復代理人　弁理士　飯　沼　義　彦 第１図 第２図Figures 1 to 3 show an overview of the conventional fin structure, with Figure 1 being a side view of the stern section with fins, and Figure 2
Figure 3 is an enlarged cross-sectional view taken in the direction of the arrow n-II in the figure, and Figure 3 is the ■-
FIG. 4 is a perspective view showing the outline of the stern of a ship equipped with a marine anti-vibration fin structure as an embodiment of the present invention, and FIG. ′-＼゛arrow sectional view. ]...Ship (L 2...Fin, 3...Propeller, 4...
Small hole. Sub-Agent Patent Attorney Yoshihiko Iinuma Figure 1 Figure 2

Claims (1)

【特許請求の範囲】[Claims] 船体外面に突設された翼状フィンの先端部に、翼上下面
に貫通する多数の防振用小孔が形成されたことを特徴と
する、舶用防振式フィン構造。A vibration-isolating fin structure for ships, characterized in that a large number of small vibration-isolating holes penetrating the upper and lower surfaces of the wing are formed at the tip of the wing-like fin that protrudes from the outer surface of the hull.