JP2008149746A - Contra-rotating propeller device for ship - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent diffusion of stream current generated by a front propeller, and to make it act on a rear propeller efficiently in a contra-rotating propeller. <P>SOLUTION: In this contra-rotating propeller device for a ship, a normal rotation propeller 1 is attached to a stern, and a reversing propeller 2 is attached by hanging a pod 7 in the rear of the normal rotation propeller. The periphery of the normal rotation propeller is surrounded by a nozzle 10 fixed in a ship's hull. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a marine contra-rotating propeller device in which propellers that rotate in the forward and reverse directions are opposed to each other.

  As a propeller device of a ship, there is a contra-rotating propeller device in which a second propeller that rotates in reverse (the pitch is also attached in the reverse direction) behind the first propeller is arranged. Since the ship propeller wake has a translational component and a rotational component, the rotational component that does not contribute to propulsion is to be taken into the rotational energy of the second propeller, thereby improving the energy efficiency.

  In this case, many propeller drive shafts have a double-shaft structure in which the drive shaft rotates forward and reverse. According to this, the structure becomes complicated and the peripheral speed is doubled to increase the bearing speed. Sealing conditions became severe and there was a problem with durability. For this reason, the forward (first) propeller is driven by a normal drive shaft, and the reverse (second) propeller is suspended by a strut and the pod is driven by a drive shaft provided in the pod. There is a propeller (for example, Patent Document 1).

However, since it is necessary to attach caps to the shaft end sides of each other's propellers, each cap exists between the two propellers, which causes the problem that the mutual propellers cannot be brought as close as necessary. . When the distance between the two propellers is separated, the wake behind the propeller accelerated by the front propeller diffuses, and the rear propeller cannot be sufficiently affected.
JP-A-6-56082

  The present invention solves the above-mentioned problems, and even when the two propellers are separated from each other, the diffusion of the propeller wake generated by the front propeller is prevented and the rear propeller is sufficiently affected. It is something that can be done.

  Under the above problems, the present invention provides a marine contra-rotating propeller device according to claim 1, wherein a forward propeller is attached to the stern, a pod is suspended behind the forward propeller, and a reverse propeller is attached. A marine contra-rotating propeller device is provided in which an outer periphery of a normal propeller is surrounded by a nozzle fixed to a hull.

  In addition, the present invention has a configuration in which the cross section of the nozzle described in claim 2 has a streamlined inner periphery, and a configuration in which the inner diameter of the nozzle is narrowed toward the rear, according to claim 3, A configuration in which the outer diameter of the blade of the reverse propeller described in claim 4 is equal to or smaller than the outer diameter of the blade of the forward propeller, and a configuration in which the rear end of the nozzle is stopped in front of the reverse propeller. The rear end of the nozzle according to claim 6 is extended to the outer periphery of the reversing propeller.

  According to the present invention, even if the front and rear propellers must be separated to some extent because of the use of separate drive systems, the water flow (rotational component) accelerated by the propeller due to the presence of the nozzle on the outer periphery of the front propeller Is prevented from diffusing and acts on the rear propeller, so there is little energy loss. The nozzle also serves as a guard that protects the propeller from drifting objects. Furthermore, since the nozzle prevents the propeller water stream from directly hitting the bottom of the vessel and causing vibration, the propeller and the bottom of the vessel can be brought close to each other. ), Increase hull volume and prevent grounding.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partial sectional side view of a main part of a stern portion of a ship. The contra-rotating propeller device according to the present invention includes a forward propeller 1 installed in front of the traveling direction and a reverse propeller 2 installed in the rear thereof. The forward propeller 1 has a plurality of blades 1b protruding from a boss 1a attached to a drive shaft 4 that protrudes toward the stern 3 and is forcibly driven. A cap 5 that covers the rear end of the drive shaft 4 is attached to the rear of the boss 1a.

  The reverse propeller 2 also has a plurality of wings 2 b protruding from the boss 2 a, extends a strut 8 that suspends the pod 7 from the bottom 6 of the rear side of the forward propeller 1, and drives a drive shaft into the pod 7. (Not shown) is mounted on the shaft, and the reverse propeller 2 is attached to the drive shaft in front of the pod 7. Similarly to the forward propeller 1, a cap 9 is attached to the front end of the boss 2a. The power transmission to the drive shaft is guided by a bevel mechanism or the like from the ship through the strut 8.

  In this example, the cores of the forward propeller 1 and the reverse propeller 2 are made to coincide with each other, and the distance between them is close as long as the caps 5 and 9 do not interfere with each other. Further, the outer diameter of the blade 2 b of the reverse propeller 2 is smaller than the outer diameter of the blade 1 b of the forward propeller 1.

  In the present invention, a nozzle 10 is attached to the outer periphery of a normal propeller 1. The nozzle 10 is attached by extending a stay 12 from the bottom 6 or the stern 3 and surrounds at least the outer periphery of the forward propeller 1 (the outer periphery of the wing 1b). At this time, the gap between the inner diameter of the nozzle 10 and the outer periphery of the blade 1b of the forward propeller 1 is set to about 0.5 to 5% of the outer diameter of the blade 1b, thereby suppressing the wake of the forward propeller 1 from diffusing. is doing. Furthermore, the cross-section of the nozzle 10 is such that the inner periphery is streamlined so that the water flow enters smoothly.

  The front and rear positions of the nozzle 10 and the forward propeller 1 are such that the tip of the nozzle 10 is positioned at least in front of the front end of the boss 1a, and the water flow that has entered the nozzle 10 is stirred by the forward propeller 1. I have to. On the other hand, the rear end may be up to the cap 5, or may be the front end position of the boss 2a of the reverse propeller 2 as shown in the partial cross-sectional side view of the main part of FIGS. In some cases, it may be extended to the extent that it takes. In the latter case, it is preferable that the inner peripheral diameter of the nozzle 10 is reduced toward the rear. This is because the downstream propeller 1 is squeezed to effectively act on the reverse propeller 2.

  By the way, since it cannot be denied that the above nozzle 10 increases hull resistance, the low speed ship is suitable for the ship to which this invention is applied, such as a tanker and a bulk carrier. Since these ships have a fertile shape, the flow of water flowing into the propeller varies greatly depending on the angle, reducing the propeller efficiency. However, the nozzle 10 has an effect of increasing the propeller efficiency by reducing the fluctuation of the water flow, and in this sense, a double effect can be expected.

  Although the above is a basic form of the present invention, the peripheral propeller 1 and the reverse propeller 2 may have different cores or may have the same rotation diameter. Further, both the forward propeller 1 and the reverse propeller 2 have a fixed pitch, and some have a variable pitch. Furthermore, there is a pod 7 in which a motor is directly charged and the reverse propeller 2 is attached to the output shaft. In addition, there are some that can rotate the strut 8, and there are some that use the rudder instead of this, and other that the strut 8 is fixed and the rudder is provided separately. Further, the reverse propeller 2 may be attached to the rear of the pod 7.

It is a partial cross section side view of the principal part of the stern part which shows this invention. It is a partial cross section side view which shows the modification of a nozzle. It is a partial cross section side view which shows the modification of a nozzle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Forward propeller 1a Boss 1b Wings 2 Reverse propeller 2a Boss 2b Wings 3 Stern 4 Drive shaft 5 Cap for forward propeller 6 Bottom 7 Pod 8 Strut 9 Reverse propeller cap 10 Nozzle 11 Stay

Claims (6)

  A marine counter-rotating propeller device in which a forward propeller is attached to the stern, a pod is suspended behind the forward propeller, and a reverse propeller is attached. The outer periphery of the forward propeller is surrounded by a nozzle fixed to the hull. A marine contra-rotating propeller device.   The marine contra-rotating propeller device according to claim 1, wherein the cross section of the nozzle has a streamlined inner periphery.   The marine counter rotating propeller device according to claim 1 or 2, wherein the inner diameter of the nozzle is reduced toward the rear.   The marine counter rotating propeller device according to any one of claims 1 to 3, wherein the outer diameter of the blade of the reverse propeller is equal to or smaller than the outer diameter of the blade of the forward propeller.   The marine counter rotating propeller device according to any one of claims 1 to 4, wherein a rear end of the nozzle is stopped in front of the counter rotating propeller.   The marine counter rotating propeller device according to any one of claims 1 to 4, wherein a rear end of the nozzle extends to an outer periphery of the counter rotating propeller.