Patent Application
20190061892
The present invention relates to a lightweight composite propeller for an outboard motor.
An outboard motor is a propulsion system that is mounted at the rear of a vessel such as a small boat and vessels can be propelled by the outboard motor. Outboard motors are usually mounted at the stern of vessels, but are mounted on small boats other than rubber boats.
Since an outboard motor is a propulsion system, outboard motors are manufactured separately from vessels. That is, an outboard motor uses an internal combustion engine, but is very different in structure and strokes from those of vehicle or motorcycles, so the manufacturer of outboard motors may be different from the manufactures of vessels.
Companies of foreign countries including Japan, have most technologies related to outboard motors, so the outboard motors that are presently on the market are unavoidably all imported. The outboard motors are complicated propulsion systems in terms of structure and are imported products, so outboard motors of 2 hp are expensive around 1.5 million Won. Accordingly, purchase of such a motor is large burden on the people who enjoy ocean sports. Further, despite of being expensive products, the outboard motors that are at present on the market are complicated in structure and sellers of outboard motors are very limited, so outboard motors are expensive and time consuming to use and maintain. Accordingly, it is urgent to develop a domestically-made outboard motor to solve this problem.
Meanwhile, the propellers for outboard motors are also imported, and expensive non-metals are used for the propellers of outboard motors to maximize anticorrosion and strength, so the propellers are heavy and difficult to manufacture in large quantities through precision casing. Further, if the propellers are damaged, their power is reduced, vibration is generated, and welding is required for repair thereof, so repair is expensive and time-consuming. Further, if the propellers are severely damaged, the entire propeller should be replaced, which is costly.
The present invention has been made in an effort to solve the problems and an object of the present invention is to provide a lightweight composite propeller for an outboard motor, wherein the propeller has a separate hub and blades that can be easily repaired when damaged, improves fuel efficiency because a lightweight composite material is used therefor, and is easily manufactured in large quantities.
In order to achieve the object of the present invention, a lightweight composite propeller for an outboard motor includes: a hub having a cylindrical body and having an axial hole at a center; blade cores disposed on an outer side of the hub; a rubber bushing disposed in the hole of the hub; and a circular ring-shaped cap disposed at a front end of the hub to prevent the blade cores from being pulled out forward from the hub, in which the blade cores are each an assembly of a blade and a core, and the core is formed by integrally coupling in advance a portion of a body which forms the outer side of the hub to a lower end of the blade, and has a structure for combining and separating the hub and the blade core.
According to the present invention, when the propeller for an outboard motor is damaged, the hub, the blades, and the rubber bushing can be easily replaced, whereby repair cost and time can be reduced. Further, the weight of the product is reduced by using a composite material, so it is possible to improve fuel efficiency and manufacture the product in large quantities.
The present invention is described hereafter in detail with reference to the accompanying drawings.
An important characteristic of the present invention is that a hub 10 and blades 21 of a propeller for an outboard motor are separated.
The hub 10 is coupled to a shaft (not shown) and the blades 21 are combined with the hub 10. When the shaft is rotated by operating an engine, the hub 10 coupled to the shaft is rotated. Accordingly, the blades 21 combined with the hub 10 are rotated, thereby generating thrust. In combination of the blades 21 and the hub 10, the hub 10 and the blades 21 are integrally formed in common propellers, so it is difficult to separate later the blades 21 from the hub 10. However, the blades 21 and the hub 10 are seperably formed in the present invention. The assembly of a blade 21 and the hub 10 can be seen from
The separable structure of the blades 21 and the hub 10 is described in detail hereafter. First, a specific separable structure called a ‘blade core’ 20 (
It is possible to combine or separate the blade 21 and the hub 10 by fitting and separating the blade core 20 on and from the hub 10 (
Meanwhile, the width of the fitting grooves 22a gradually decreases as it goes to the center of the shaft (
The detailed structures of the fitting grooves 20a and the fitting projections 10a are as follows. A bending portion 22a-1 is formed at a first side of each of the fitting grooves 22a by bending both ends of the core 22 toward the center of the shaft and a fitting portion 22a-2 extending toward the center of the shaft is formed at a second side of each of the fitting grooves 22a to face the bending portion 22a-1 with the fitting grooves 22a therebetween (
This is a very important matter in a separable device (product) like the present invention. This is because although a separable device is manufactured to be separable, if the device is easily disassembled after assembled, it may be critically defective in terms of firmness and durability. However, the coupling structure of the fitting grooves 22a and the fitting projections 10a is configured as described above in the present invention so that the blade cores 20 and the hub 10 can be easily separated, but once they are combined, they are not easily disassembled.
Meanwhile, since the fitting groove 22a is covered with the bending portion 22a-1, the fitting portion 22a-2, and the core 22 at the first side, the second side, and the top, respectively, the fitting projections 10a are hidden not to be exposed to the outer side by the cores 22 when the propeller is assembled. Therefore, according to the present invention, it is possible to prevent damage to the fitting projections 10a, that is, the hub 10 in a broad sense. That is, the propeller frequently hits against objects under water while a vessel is sailed, so if an object directly hits against a fitting projection 10a and the fitting projection 10a is damaged or broken, the entire hub 10 should be replaced. Obviously, repairing is difficult and costs a lot of money in this case. However, according to the present invention, since the fitting projections 10a are not exposed to the outside and the parts that may hit against floating object in water are limited not to the fitting projections 10a or the hub 10, but only to the blade cores 20. Accordingly, if a blade core 20 is damaged or broken by hitting against an object under water, it is possible to simply repair the propeller by replacing only the blade core 20. As described above, the present invention has a considerable advantage even in terms of maintenance.
A stopper step 11 is formed at the rear end of the hub 10 (
A circular ring-shaped cap 40 is fitted on the front end of the hub 10 after the blade cores 20 are fitted on the hub 10 (
Since expensive non-metal is used to maximize the anticorrosion and strength of existing propellers for an outboard motor in the related art, the propellers are heavy and difficult to manufacture in large quantities through precision casing. For this reason, the hub 10 is made of aluminum and, the blade cores 20 and the cap 40 are made of a composite material in the present invention, thereby securing anticorrosion and strength of the product and reducing the weight. In particular, the blade cores 20 and the cap 40 are manufactured by injection-molding a composite material so that the product can be manufactured in large quantities and the manufacturing cost can be reduced.
An axial hole 12 is formed through the center of the hub 10 and a rubber bushing 30 is disposed in the hole 12 (
Accordingly, the rubber bushing 30 in the present invention is designed to have an appropriate size so that it can be easily replaced by a person, that is, the diameter of the rubber bushing 30 may be designed to be 5 to 10 mm smaller than the diameter of the hole 12. In this case, since the rubber bushing 30 is made of rubber, it is sufficiently possible for a person to reduce the diameter of the rubber bushing 30 by 5 to 10 mm when pushing the rubber bushing 30 into the hole 12. The rubber bushing 30 inserted in the hole 12 is close contact with the hole 12 due to the elasticity of rubber, so it is tightly fitted in the hub 10. In contrast, it is also sufficiently possible to manually pull out the rubber bushing 30 in order to replace the rubber bushing 30.
As described above, according to the present invention, when the propeller for an outboard motor is damaged, the hub 10, the blades 21, and the rubber bushing 30 can be easily replaced, so repairing requires less cost and time. Further, the weight of the product is reduced by using a composite material, so it is possible to improve fuel efficiency and manufacture the product in large quantities.
According to the present invention, repairing takes less cost and time when the propeller for an outboard is damaged, fuel efficiency can be improved by using a composite material, and the propeller can be manufactured in large quantities. Therefore, the present invention can achieve practical and economic values through wide use in shipbuilding and marine engineering fields.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20-2016-0002722 | May 2016 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2017/005045 | 5/16/2017 | WO | 00 |
