JPH11314598A - Reinforced plastic-made propeller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress cavitation, enhance corrosion resistance, and simultaneously provide high strength, light weight and high efficiency, by manufacturing a propeller with reinforced plastic reinforced by fiber. SOLUTION: A propeller 10 is manufactured with reinforced plastic reinforced by fiber serving as raw material. This fiber is preferably carbon fiber. The carbon fiber is oriented in the parallel direction to a skew line S. Since this propeller 10 has the material in high strength, blade thickness can be thinned, and efficiency of the propeller can be improved. Because of small specific gravity, weight can be lightened, inertia moment is decreased, and acceleration performance of a propeller shaft can be enhanced. Further, since the carbon fiber is oriented in the parallel direction to the skew line S, resistance to force tending to bend a blade is strong, resistance to twisting force is not so strong, since changing of a pitch due to resistance of water is relatively easy, and cavitation can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforced plastic propeller manufactured by using a reinforced plastic as a propeller used as a propulsion device of a ship.

[0002]

2. Description of the Related Art Conventionally, a propeller used for a ship has been manufactured by casting a metal that does not rust. Generally, a propeller receives a large resistance at the time of acceleration, such as at the time of start-up, and the load is larger at the tip of the blade where the turning radius becomes larger. For this reason, this portion is overloaded and cavitation occurs. When cavitation occurs, it causes hull vibration and causes erosion on the wing surface.

[0003] In addition, electric corrosion (electrolytic corrosion) of a propeller due to a potential difference from seawater also occurs. For this reason, nickel aluminum-based bronze or the like having a small potential difference is used, but electrolytic corrosion cannot be completely suppressed. Furthermore, metal materials are heavy,
It requires a large driving torque and is inconvenient to handle. The present invention solves such a problem, and embodies a propeller excellent in all required characteristics.

[0004]

SUMMARY OF THE INVENTION Under the above-mentioned problems, the present invention relates to a fixed pitch type propeller used for a ship,
A propeller made of reinforced plastic, characterized in that the propeller is made of reinforced plastic reinforced with fiber.

[0005] The use of reinforced plastic as the material of the propeller suppresses cavitation and provides excellent corrosion resistance, but at the same time enables a high-strength, light-weight, and high-efficiency propeller.

The present invention also provides a reinforced plastic propeller in which the above-mentioned fibers are carbon fibers, and the orientation direction of the carbon fibers is in the direction of the skew line. Since carbon fibers are hard and have high tension, the strength of the plastic containing them is also high. Generally, when a fiber is put into a plastic, it is strong against an external force having a line perpendicular to the orientation direction of the fiber as a bending surface, and not so much as an external force having a parallel line as a bending surface. Therefore, it is strong against wing bending and not so strong against torsion. This is preferable for the propeller, but will be described later in detail.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a propeller showing an example of the present invention, and FIG. 2 is a top view. The shape of the propeller 10 itself is not different from that of a conventional metal propeller. What will change is the use of reinforced plastics reinforced with fibers. Although there are various types of fibers, carbon fibers are most preferable in consideration of strength and the like. However, besides this, glass fiber and aramid fiber are also conceivable.

When the propeller 10 is made of reinforced plastic, the boss 10a and the entire wing 10b are made of reinforced plastic, and the boss 10a is made of metal.
There is a case where only b is made of reinforced plastic. The case where the entire boss 10a and the entire wing 10b are formed of a plastic containing fiber will be described.

In the case of molding a shape such as the propeller 10 with plastic, it depends on a contact pressure molding method or a high-pressure or low-pressure pressure molding method. In the present invention, any of them may be used. . In short, it is only necessary that the propeller 10 can be formed into the shape. The type of plastic (resin) used is not limited, but polyester, vinyl ester, epoxy, and the like are generally used. Further, the carbon fiber to be mixed may be either a short fiber or a long fiber, and the compounding ratio thereof is 20 to 6
A standard value of about 0 wt% may be used.

On the other hand, when the boss 10a is made of metal and only the wing 10b is made of reinforced plastic, the boss 10a is also molded and molded simultaneously and integrally with the wing 10b. And fixing to the boss 10a which has been manufactured in advance by bonding, welding, fastening, or the like. In the latter case, since only one kind of the blade 10b having a relatively simple shape may be manufactured, it can also be manufactured by a continuous forming method in which carbon fibers are directly wound around a mold, and the degree of freedom of the forming method is increased.

The reinforced plastic propeller 10 has the following features. First, there is a high strength point due to the characteristics of the material. In the case of carbon fiber-containing resin (CFRP), the tension is higher than that of ordinary aluminum bronze (1).
200 N / mm ² ), which is advantageous in that the blade thickness can be reduced. If the blade thickness can be reduced, the efficiency of the propeller can be improved.
10%). In addition, since the specific gravity is small (about 1.5), the total weight can be reduced to about 1/3 of the nickel aluminum bronze.
The reduction in weight in this manner is excellent in handleability at the time of work, reduces the moment of inertia, and contributes to increasing the acceleration of the propeller shaft.

Further, the occurrence of cavitation is suppressed.
For this, it is necessary to consider a method of orienting carbon fibers mixed in a product (propeller). Specifically, the wing 10b
Is that the carbon fibers are oriented in the radial direction. That is,
Since each blade 10b extends in the radial direction with a constant skew angle α, the carbon fibers are oriented in a direction parallel to the skew line (S). By orienting the carbon fibers in this direction, as described above, the resistance to bending the wing is strong, and the force to twist is not so low.
Changing the pitch is relatively easy due to the resistance of the water.

That is, each blade 10b is twisted at a pitch angle β (β is set to be smaller as the radius becomes larger so that the pitch becomes the same over the entire length of the blade 10b), and when the propeller 10 rotates, Since the blade surface receives water resistance, the blade 10b is twisted in a direction to decrease the pitch angle β. The degree of the torsion increases as the resistance of the water increases, so that the pitch angle β decreases as the acceleration of the propeller 10 increases and as the radius increases.

Further, the skew angle α increases the torsion on the trailing edge side of the blade 10b from the leading edge side, so that the pitch angle β is further reduced. For this reason, the stress applied to the wing surface does not become too large, and the occurrence of cavitation is suppressed. Also, the acceleration of the propeller shaft is enhanced. In addition, the suppression of erosion due to the high erosion resistance due to the characteristics of the material also contributes to the suppression of cavitation.

In addition, the fact that the wing thickness can be reduced and cavitation can be suppressed means that hull vibration and underwater noise are reduced. In addition, since plastic has strong chemical properties against seawater, corrosion resistance is improved. In addition, there is no need to worry about electrolytic corrosion unlike a metal material.

[0016]

As described above, according to the present invention, a propeller excellent in all characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of a propeller showing an example of the present invention.

FIG. 2 is a top view of a propeller showing an example of the present invention.

[Explanation of symbols]

 10 Propeller 10a Propeller boss 10b Propeller wing S Skew line

Claims (4)

[Claims] 1. A reinforced plastic propeller for use in a ship, wherein the propeller is made of reinforced plastic reinforced with fibers. 2. The reinforced plastic propeller according to claim 1, wherein the fibers are carbon fibers, and the orientation direction of the carbon fibers is in the direction of the skew line. 3. The reinforced plastic propeller according to claim 1, wherein the propeller comprises a boss and a wing, and the boss and the wing are integrally formed of reinforced plastic. 4. The reinforced plastic propeller according to claim 1, wherein the propeller comprises a boss and a wing, and a reinforced plastic wing is fixed to the metal boss.