JP2019156095A - Propeller boss cap with fin - Google Patents

Abstract

To provide a propeller boss cap with a fin, which can be manufactured at lower cost than a conventional product.SOLUTION: A boss cap is attached to a propeller boss, and in regards to the boss cap with a plural of fins attached to an outer peripheral surface, a plastic plate fin is welded to fix or is bonded to fix to an outer peripheral surface of the boss cap of a hollow plastic welded structure or a hollow plastic bonded structure to reduce a hub vortex generated in a boss cap wake.SELECTED DRAWING: Figure 1

Description

The present invention relates to a propeller boss cap with fins.

A boss cap attached to a propeller boss and having a plurality of fins attached to the outer peripheral surface in order to reduce hub vortex generated in the wake of the boss cap is disclosed in Patent Document 1 and the like.
Propellers and finned propeller boss caps are generally manufactured by propeller manufacturers. From the viewpoint of corrosion resistance against seawater and erosion resistance against propeller cavitation, the propeller is generally an aluminum copper alloy casting, and from the viewpoint of consistency in manufacturing operations, the finned propeller boss cap is also an aluminum copper alloy casting. Met.

Japanese Examined Patent Publication No. 7-121716

A conventional propeller boss cap with fins, which is a cast product of an aluminum copper alloy, has a problem that the manufacturing cost is high because of expensive material costs and a large number of manufacturing steps.
This invention is made | formed in view of the said problem, It is a propeller boss cap with a fin, Comprising: It aims at providing the propeller boss cap with a fin whose manufacturing cost is remarkably low compared with a conventional product.

In order to solve the above problems, in the present invention, a boss cap attached to a propeller boss, wherein a plurality of fins are attached to the outer peripheral surface in order to reduce hub vortex generated in the wake of the boss cap. The present invention provides a finned propeller boss cap characterized in that fins of a plastic plate are welded or fixed to the outer peripheral surface of a boss cap which is a hollow plastic welded structure or adhesive structure.
A propeller boss cap with a fin, in which a fin of a plastic plate is welded or fixed to the outer peripheral surface of a boss cap, which is a hollow plastic welded structure or adhesive structure, is a conventional fin made of cast aluminum copper alloy. Compared to the attached propeller boss cap, the material cost is lower and the number of manufacturing steps is smaller, so the manufacturing cost is much lower. Moreover, since plastic is lighter than aluminum copper alloy products, the weight of the propeller boss cap with fins is reduced, and the polar moment of inertia of the propeller rotating system is reduced, thereby improving the fuel efficiency of the ship.
Since the peripheral speed of the propeller boss cap fin is small, cavitation does not occur. Therefore, even if the material is plastic, no erosion occurs. Since the bending moment acting on the fin is small, there is no problem in strength even if the material is plastic. Since plastic does not cause corrosion by seawater, no countermeasures against corrosion are required.
Further, in the present invention, a boss cap attached to a propeller boss, wherein the boss cap has a plurality of fins attached to the outer peripheral surface in order to reduce hub vortex generated in the downstream of the boss cap. There is provided a propeller boss cap with a fin including a boss cap and a plastic fin, wherein the boss cap and the fin are integrally formed by a 3D printer.
Instead of the propeller boss cap with fins having a multiple-member welding structure or an adhesive structure, the fins may be integrally formed using a 3D printer.
The connection part between members is lost, and the strength is improved.

In a preferred embodiment of the present invention, the boss cap is a cylindrical body.
A cylindrical plastic boss cap having no double curved surface can be easily manufactured using a commercially available plastic pipe and a plastic plate, and contributes to a reduction in manufacturing cost by reducing the number of manufacturing steps. Even when the three-dimensional printer is integrally formed, simplification of the structure contributes to a reduction in manufacturing cost.
In a preferred embodiment of the present invention, the fin thickness decreases from the base near the boss cap toward the top.
By reducing the plate thickness of the fins from the base part near the boss cap toward the top part, the weight of the propeller boss cap with fins is reduced, and the polar moment of inertia of the propeller rotating system is reduced, thereby improving the fuel efficiency of the ship.

By this invention, it is a propeller boss cap with a fin, Comprising: The manufacturing cost with a fin lower than the conventional product is provided.

It is an external appearance perspective view of a propeller boss cap with a fin concerning the example of the present invention, and a propeller provided with the boss cap concerned.

A finned propeller boss cap according to an embodiment of the present invention will be described.
As shown in FIG. 1, a propeller boss cap 1 with a fin is provided with a boss cap 2 which is a hollow plastic welded structure or an adhesive structure, and is arranged on the outer peripheral surface of the boss cap 2 at equal intervals in the circumferential direction. And a plurality of plastic plate fins 3 fixed by welding or adhesively. The boss cap 2 has a cylindrical body 2a, a circular end plate 2b that is welded or fixed to one end of the cylindrical body 2a to close the one end, and an outer ring that is welded or fixed to the other end of the cylindrical body 2a. And a flange 2c. The outer flange 2c is fixed to the end surface of the propeller boss A with a bolt (not shown).
The boss cap 2 and the fin 3 are made of high density polyethylene resin (HDPE). A commercially available plastic pipe used for a water pipe or the like is used for the cylindrical body 2a of the boss cap 2, and a commercially available plastic plate is used for the end plate 2a and the outer flange 2c.

The propeller boss cap 1 with fins, in which the fins 3 of the plastic plate are welded or fixed to the outer peripheral surface of the boss cap 2 which is a hollow plastic welded structure or adhesive structure, is a cast aluminum alloy. Compared to a conventional propeller boss cap with fins, the material cost is low and the number of manufacturing steps is small, so the manufacturing cost is much lower. Further, since the plastic is lighter than the aluminum copper alloy product, the weight of the propeller boss cap 1 with fins is reduced, and the polar moment of inertia of the propeller rotating system is reduced, thereby improving the fuel efficiency of the ship.
Since the peripheral speed of the fin 3 of the propeller boss cap 1 is small, cavitation does not occur. Therefore, even if the material of the fin 3 is plastic, no erosion occurs. Since the bending moment acting on the fin 3 is small, there is no problem in strength even if the material of the fin 3 is plastic. Since plastic does not cause corrosion by seawater, no countermeasures against corrosion are required. The high-density polyethylene resin is excellent in mechanical strength and water resistance and is suitable as a plastic material for the propeller boss cap 1.
The cylindrical plastic boss cap 2 having no double curved surface can be easily manufactured by using a commercially available plastic pipe and a plastic plate, and contributes to a reduction in manufacturing cost by reducing manufacturing man-hours.
In the boss cap 2 of the cylindrical body, the strength of the hub vortex generated in the wake of the boss cap is almost the same as that of the conventional boss cap having a shell shape.
The plate thickness distribution of the fins 3 may be uniform, but may be decreased continuously or discontinuously from the base portion near the boss cap 2 toward the top portion. The weight of the propeller boss cap 1 with the fin is reduced, and the polar moment of inertia of the propeller rotating system is reduced, thereby improving the fuel efficiency of the ship.
The cylindrical body 2a may be replaced with a truncated cone-shaped cylinder, but in this case, labor for processing a commercially available plastic plate into a truncated cone-shaped cylinder is generated.
Other high strength plastics may be used in place of the high density polyethylene resin.
The finned propeller boss cap 1 may be integrally formed by using a 3D printer instead of a plural-member welding structure or an adhesive structure. The connection part between members is lost, and the strength is improved.
Even when the three-dimensional printer is integrally formed, simplifying the structure by using the boss cap 2 as a cylinder contributes to a reduction in manufacturing cost. Although the cylindrical body 2a may be replaced with a truncated cone-shaped cylindrical body, the manufacturing cost increases due to the complicated shape.
When integrally forming using a 3D printer, the plate thickness distribution of the fins 3 may be uniform, but may be decreased continuously or discontinuously from the base near the boss cap 2 toward the top. The weight of the propeller boss cap 1 with the fin is reduced, and the polar moment of inertia of the propeller rotating system is reduced, thereby improving the fuel efficiency of the ship.

The present invention can be widely used for a propeller boss cap with a fin.

DESCRIPTION OF SYMBOLS 1 Propeller boss cap with fin 2 Boss cap 2a Cylindrical body 2b Circular end plate 2c Annular outer flange 3
Fin A Propeller Labs

Claims (4)

A boss cap attached to a propeller boss, in which a plurality of fins are attached to the outer peripheral surface in order to reduce hub vortex generated in the downstream of the boss cap. A propeller boss cap with a fin, wherein a fin of a plastic plate is welded or bonded and fixed to the outer peripheral surface of the boss cap. A boss cap attached to a propeller boss, wherein the boss cap has a plurality of fins attached to the outer peripheral surface in order to reduce hub vortex generated in the wake of the boss cap, and a boss cap that is a hollow plastic structure; A propeller boss cap with a fin, comprising a plastic fin, wherein the boss cap and the fin are integrally formed by a 3D printer. The boss cap is a cylindrical body, and the propeller boss cap with fins according to claim 1 or 2. The propeller boss cap with fins according to any one of claims 1 to 3, wherein the plate thickness of the fins decreases from the base portion near the boss cap toward the top portion.

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