JPH0537695U - Anti-vibration device for marine flats ladder - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a flap ladder that can prevent vibration and noise by providing a rod-shaped projection on the flap rudder. [Structure] The length of the flap rudder 3 is approximately the chord length L of both sides of the flap rudder 3, and one side face is raised forward, while the other side face is raised backward, respectively from the horizontal to 20 degrees. The height and width of the flap rudder 3 are both asymmetrical by 2 to 5% of the chord length L of the flap rudder 3, and the number is 6 to 15 per side surface of the flap rudder 3. Individual rod-shaped projections 6 are provided. As a result, the periodic vortices and turbulence of the Karman vortex-like water flow generated near the flap rudder are eliminated, and the causes of noise and vibration are eliminated.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a vibration preventing device for a marine flap ladder.

In the present specification, the “flapp rudder” refers to the entire rudder device including the flap rudder, and the “flap rudder” refers to one component in the flap rudder.

[0003]

[Prior art]

 As shown in the horizontal sectional view of FIG. 3, the flap ladder has a rudder plate with a rudder area smaller than that of the main rudder 1 and a main rudder 1 rotatably attached to the rear edge of the main rudder 1 via a joint (hinge) 4. It is divided into a rudder (flap rudder) 3, and the flap rudder 3 is interlocked with the rudder angle of the main rudder 1 by the function of the interlocking device 5 (see FIG. 1) to further take its own rudder angle with respect to the main rudder 1, Therefore, it is known as a device that can increase the lateral thrust of the entire rudder and turn the hull with a smaller radius.

[0004]

[Problems to be solved by the device]

 As described above, the flap rudder 3 is attached to the rear edge of the main rudder 1 via the joint 4, but during operation, the flap rudder 3 vibrates left and right due to the water flow, damaging the mechanism, and causing unpleasant noise. Can be the source of It is because the joints 4 to which the flap rudder 3 is attached and the interlocking device 5 (Fig. 1) from the main rudder 1 to the flap rudder 3 have mechanical "rattles" that are originally unavoidable. It is considered that this is caused by the addition of external force due to periodic vortices such as Karman vortex 8 and turbulence generated in the water flow.

Originally, since the rudder angle is zero (neutral) when the ship goes straight, external force is not applied to the flap rudder in either direction in principle. However, even in such a case, if a periodic vortex or turbulence occurs in the water flow as described above, it will be added to the flap rudder as a periodic external force from the left and right. Moreover, since most of the operating time of the ship is straight ahead, not only does it continue to emit noise during that time, but external force in the plus and minus directions centered around zero is also the flap rudder joint and interlocking device for a long time. Repeatedly working on the structure damages the mechanism, impairs its original function, and mechanically increases the “rattle” at an accelerating rate, requiring a great deal of labor for repair. This kind of problem also exists in a ship side thruster and the like, and one solution has already been given by the present applicant (see Japanese Utility Model Publication No. 60-1040). In this case, the projections are spirally wound around the input shaft pod of the side thruster, but in the case of the flap ladder, the main rudder is connected to the flap rudder and this configuration is not possible. Absent.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a vibration preventive device for a flap ladder capable of preventing vibration and noise by providing a predetermined rod-shaped projection on the flap rudder.

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the anti-vibration device for a marine flap ladder according to the present invention has a length of at least approximately the chord length of the flap rudder, and one side is raised forward and the other side is raised backward from the horizontal. A plurality of rod-shaped projections are arranged in a row in the vertical direction on both sides of the flap rudder, respectively, inclining at a gradient of 20 to 40 ° and asymmetrically to the left and right. 2 to 5%, and the number of the rod-shaped projections on one side of the flap rudder is set to 6 to 15.

[0008]

[Action]

 In the above configuration, the periodic vortices and turbulence of the Karman vortex-like water flow that occurs in the vicinity of the flap rudder as shown in FIG. It is dismantled by the multiple rod-shaped protrusions placed in, and the cause of noise and vibration is eliminated.

[0009]

【Example】

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

In FIG. 1, a main rudder 1 is supported and steered by a rudder shaft 2 pivotally supported by a hull H. A flap rudder 3 having a small rudder area is pivotally attached to the rear edge of the main rudder 1 via upper and lower joints (hinge) 4. This flap rudder 3 is connected to an interlocking device 5 provided on the upper part of the rudder, and interlocks with the rudder angle of the main rudder 1 to the main rudder 1 in the same direction as the main rudder 1 and of its own size. You can take a corner. Therefore, for example, when the main rudder 1 is turned to the right, the flap rudder 3 is turned to the right rudder with respect to the main rudder 1 by the interlocking device 5, and the two rudders are combined to generate a larger lateral thrust to strongly turn the hull. Can be made.

As shown in FIGS. 1 and 2, the lengths of both sides of the flap rudder 3 extend substantially along the chord length L of the flap rudder 3, and one side surface rises forward and the other side surface extends backward. The bar-shaped projections 6 of the required size and number are arranged in a line asymmetrically from the horizontal at an inclination of an angle α.

The angle α of the inclination of the rod-shaped projection 6 is set to 20 ° to 40 °. If the angle α is smaller than 20 °, the horizontal asymmetry of the projection is small and the Karman vortex 8 (Fig. 3) cannot be broken down. If the angle α is larger than 40 °, the angle of the rod-shaped projection 6 falls with respect to the water flow. Similarly, the effects diminish.

The height h (FIG. 2) and the width a (FIG. 1) of the cross section of the rod-shaped projection 6 are both within a range of 2 to 5% of the chord length L of the flap rudder 3. If it is smaller than this, the effect of eliminating the vortex is not provided, and if it is larger, the resistance of the rudder to the forward water flow becomes too large.

The number of rod-shaped projections 6 is 6 to 15 per one side surface of the flap rudder 3. In this case as well, if the amount is too small, there is no effect, and if the amount is too large, the resistance increases.

The rod-shaped projections 6 having the above-mentioned length, mounting angle, cross-sectional size (a × h) and the number of rod-shaped projections 6 are prepared, for example, with steel rods, and fixed to the main surface of the flap rudder 3 by welding. However, of course, as long as the size and quantity are in the above range, casting or other known method may be used depending on the situation.

If necessary, rod-shaped projections 7 on both side surfaces of the flap rudder 3 are provided in front of the flap rudder 3, that is, in the rear of the main rudder 1 as well as rod-shaped projections 7 of the same number and size as those of the flap rudder 3 described above. 6 may be arranged in a line so as to extend.

[0017]

[Effect of the device]

 Since the present invention is configured as described above, periodic vortices and turbulence of the Karman vortex-like water flow that occurs in the vicinity of the flap rudder and grows bilaterally to the rear are eliminated, and the cause of noise and vibration is eliminated. To be done. Therefore, it is possible to solve the problems that noise continues to be generated during straight traveling, which makes up most of the operating time of the ship, and that vibrations add to the flap rudder joints and interlocking device and damage the mechanism, requiring a great deal of labor for repair.

[Brief description of drawings]

FIG. 1 is a side view of a flap ladder according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a horizontal cross-sectional view showing a generation state of Karman vortices behind a conventional flap ladder.

[Explanation of symbols]

 1 ... Main rudder 2 ... Rudder head shaft 3 ... Flap rudder 4 ... Joint 5 ... Interlocking device 6, 7 ... Rod-shaped projection 8 ... Karman vortex

Claims (1)

[Scope of utility model registration request] 1. At least the length of the flap rudder is approximately the chord length of the flap rudder. One side of the rudder is inclined forward to the front and the other side is inclined rearward to be inclined from the horizontal to a gradient of 20 to 40 °, respectively, which are asymmetrical. A plurality of bar-shaped projections are vertically arranged on both sides of the flap rudder, and the height and width of the bar-shaped projections are both 2 to 5% of the flap rudder chord length, and A vibration preventing device for a marine flap ladder, wherein the number of the rod-shaped projections is set to 6 to 15.