JPS6112496A - Ship propeller unit - Google Patents

Abstract

PURPOSE:To satisfactorily restrain cavitation errosion, by covering all or a part of forward and backward surfaces of a propeller body with an ultra-high molecular weight polyethylene resin having a molecular weight of more than 100 millions. CONSTITUTION:A polyethylene resin is coated on a propeller body of a ship propeller unit to enhance the anti-cavitation errosion characteristic of the propeller. Therefore, the propeller may be designed without deteriorating its propeller efficiency. Further, if an ultra-high molecular weight polyethylene resin having a molecular weight of more than 100 million, preferably from 300 million to 600 million, is used, the anti-cavitation errosion may be further enhanced to raise the propeller efficiency. This resin is very hard so that it is difficult to be damaged, and therefore, the original surface condition may be maintained. Further, the anti-errosion ability may be enhanced to make sea creatures difficult to adhere to the propeller, and vibration and noise of a ship may be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a marine propulsion device, and more particularly, to an improvement of a metal propeller for a marine propulsion device.

(Prior Technology) As is well known, most marine propulsors have conventionally been manufactured from copper alloys mainly consisting of manganese bronze and aluminum bronze, and in rare cases ferrous materials such as cast steel and cast iron have also been used. However, in recent years, the problem of cavitation erosion occurring in propellers has become more prominent as ships have become larger and the diameters and speeds of marine propulsors have increased. When cavitation erosion occurs, the roughness of the propeller surface decreases, water resistance increases, propeller torque increases, and propulsion efficiency decreases. This cavitation erosion is essentially a design problem, but it is difficult to completely eliminate it with current design technology, so cavitation erosion is suppressed at the expense of propeller efficiency. is the reality.

For this reason, attempts have been made to coat the propeller body of a marine propulsion device with a polymer material (Japanese Patent Laid-Open No. 58-36
Publication No. 794). Although this publication does not mention specific polymer materials, for example, rubber-based materials such as natural rubber, acrylonitrile-butadiene copolymer rubber, etc.
0-385), or those obtained by curing an epoxy resin containing an inorganic reinforcing material with a polyamide-based or amine-based curing agent (JP-A-50-154330). However, each of these has the following disadvantages.

(Problem to be solved by the invention) In other words, although the former method can suppress cavitation erosion to some extent, it has the disadvantage of a high coefficient of friction with water and poor propulsion efficiency for ships, and the heat generated by the occurrence of cavitation causes damage to the coating. Another drawback is that the material deteriorates. In addition, although the latter has the advantage that the propellers of marine propulsion units are less likely to corrode when navigating through coastal waters contaminated with industrial wastewater flowing out from various factories, it is said that it does not effectively suppress cavitation erosion. There are disadvantages.

The present invention aims to solve all of the above-mentioned disadvantages, that is, it can suppress cavitation erosion well, has excellent corrosion resistance, and has a low coefficient of friction with water, thereby improving the propulsion efficiency of ships. That is.

(Means for Solving the Problems) That is, the present invention is a marine propulsion device in which all or part of the forward and reverse moving surfaces of the propeller body are coated with polyethylene resin,
More preferably, the present invention relates to a marine propulsion device in which a propeller body is coated with an ultra-high molecular weight polyethylene resin having a molecular weight of 1 million or more.

The polyethylene resin used in the present invention is the most produced resin along with vinyl chloride resin, is an inexpensive general-purpose resin, has a light specific gravity of 0.91 to 0.97, and has excellent cold resistance and electrical insulation. It does not absorb or permeate water, has excellent oil, acid, and organic solvent resistance, and also has the property of absorbing vibration and sound.

The present inventors arrived at the present invention by discovering that when the propeller body of a marine propulsion device is coated with this polyethylene resin, cavitation erosion can be suppressed well.

As described above, the present invention utilizes polyethylene resin, which has been conventionally known as a general-purpose resin, in special parts, thereby achieving effects hitherto unknown.

Molecules especially as polyethylene resin! When using a so-called ultra-high molecular weight polyethylene resin with a molecular weight of 1 million or more, preferably between 3 million and 6 million, it has increased strength and rigidity compared to conventional high-density polyethylene resin, is less likely to break, and also has better weather resistance and slipperiness. Becomes good. Therefore, it is preferable to use this so-called ultra-high molecular weight polyethylene resin as a material for ships.

Methods for coating the propeller body of a marine propulsion device with polyethylene resin include, for example, a method in which liquid polyethylene resin dissolved in a solvent is applied to the propeller body by spraying or brush coating, and a method in which polyethylene resin is melted at high temperature is applied. A method of applying polyethylene resin using a brush coating method, a method of pasting a polyethylene resin sheet and a propeller body with an adhesive, a method of sandwiching an adhesive inclusion between a polyethylene resin sheet and a propeller body, and pasting it with an adhesive. An appropriate method is adopted.

(Functions and Effects of the Invention) According to the present invention, since the propeller body of the marine propulsion device is coated with polyethylene resin, the following effects can be achieved.

(a) Since the cavitation erosion resistance is excellent and the occurrence of cavitation erosion is suppressed, propellers can be designed without sacrificing propeller efficiency, thus increasing the propulsion efficiency of ships. . Also, the molecular weight is 1 million or more, preferably 3
If an ultra-high molecular weight polyethylene resin having a molecular weight of 1,000,000 to 6,000,000 is used, the cavitation erosion resistance can be further improved.

The surface of polyethylene resin can be made smoother than the polished surface of conventional metal propellers, and because marine organisms are less likely to adhere to it, the frictional resistance between the propeller and water is reduced. Therefore, propeller torque can be reduced and propulsion efficiency can be increased.

Furthermore, when ultra-high molecular weight polyethylene resin with a molecular weight of 1 million or more is used, this resin is hard and difficult to damage, making it possible to maintain the original surface condition and preventing a decrease in propulsion efficiency. can.

The fcl polyethylene resin surface has superior corrosion resistance compared to metal surfaces. Therefore, corrosion of the propeller can be suppressed even when navigating in sea areas contaminated with industrial wastewater. Moreover, if an ultra-high molecular weight polyethylene resin with a molecular weight of 1 million or more, preferably 3 million to 6 million is used,
Furthermore, corrosion resistance can be improved.

Since the FDL polyethylene resin surface is smoother than a metal surface, marine organisms are less likely to adhere to it during navigation. Therefore, it is possible to reduce the amount of propeller cleaning and polishing work that is performed every time the propeller is tonked. Furthermore, if an ultra-high molecular weight polyethylene resin having a molecular weight of 1 million or more, preferably 3 million to 6 million, is used, the amount of cleaning and polishing of the propeller can be further reduced due to the above-mentioned factors and resistance to damage.

(81 Polyethylene resin has the property of absorbing vibration and sound, so if it is coated on the propeller body of a marine propulsion device, the vibration and noise of the vessel can be reduced.

(Test example) Aluminum bronze, epoxy, nylon 11. Prepare plate-shaped specimens of resins such as Teflon, vinyl chloride, conventional high-density polyethylene, and ultra-high molecular weight polyethylene with a molecular weight of approximately 3 million to 6 million. tested by law,
The damage weight was measured.

The results are shown in FIG. As is clear from this, polyethylene resin has extremely low damage weight compared to other materials, and is effective in suppressing cavitation erosion.

(Example) An ultra-high molecular weight polyethylene resin with a molecular weight of about 3 million to 6 million is cut into a tile shape of 500 m x 500 m, and after degreasing, a heat-sensitive adhesive polyolefin resin film (here, Idemitsu) is applied to the surface to be adhered. manufactured by the petrochemical company, using an Idemitsu poly tank) at a temperature of 160°C and a pressure of 10k.
The pressure bonding was carried out under conditions of gf /cnl and a time of about 1 minute. Next, that surface was placed on the surface of an aluminum bronze propeller at a temperature of 140 to 170°C and a pressure of 2 to 10 kgf/cJ.
They were bonded for about 1 minute and cooled under pressure. Prior to joining, the propeller adhesion surface is roughened (surface roughness 10 to 50 μm) using a sander or blasting machine, and then
Degreased.

When applying pressure, since the propeller body has a curved surface, pressure is applied through an elastic material so that pressure is applied uniformly to the entire surface, and when arranging tiles, it is necessary to make sure that there are no gaps between the joints. I glued it in place.

Peel strength of the ultra-high molecular weight polyethylene resin of the propeller obtained in the above examples (JIS K 6854: 18
0 peel test) was approximately 2Qkgf/25'm, which was good.

[Brief explanation of drawings]

FIG. 1 is a graph showing the results of measuring the damaged weight of various materials using a magnetostrictive vibration type cavitation tester, where the horizontal axis shows the type of material and the vertical axis shows the damaged weight.

Claims (1)

[Scope of Claims] 1. A marine propulsion device characterized in that all or part of the forward and reverse moving surfaces of the propeller body are coated with polyethylene resin. 2. The marine propulsion device according to claim 1, wherein an ultra-high molecular weight polyethylene resin having a molecular weight of 1 million or more is used as the polyethylene resin.