LV14429B - Vibrating actuator of hydrodynamic fin - Google Patents

Abstract

The invention relates to drives of water vehicles, and it can be used for the propulsion of objects floating under water: fishes-robots, submarines, etc. Its purpose is to increase the working efficiency of fin vibrating actuator, i.e., improve its floating stability and staying on the required heading course, increase propulsion efficiency, and decrease hydrodynamic resistance of its housing. The objective is reached by the hydrodynamic fin vibrating actuator, consisting of a drive, the transmission mechanism and two identical fins implemented as thin-walled elements in the form of half-cylinders, the convex part of which is directed outside from an axis of floating object, but the concave part of it is directed inside. The axes of rotation of fins are located in the forepart of their housing. The fins are generating propulsion force. The internal surfaces of fins completely coincide with the external surface of the housing and fit tight to the housing during the phase of their closing up to it. The load bearing surfaces (wings) are arranged over the fins in the upper and bottom part. They are thin rigid plates having triangular form in the plain. The top and bottom horizontal edges of fins during their reaching-out coincide with fore-edges of wings, i.e., the length of the wings attached to the housing coincide with the length of fins.

Description

Description of the Invention

The invention relates to the propulsion of watercraft and can be used for the movement of submersible craft (robotic fish, submarines, etc.).

Analysis of known state of the art

Hydrodynamic fin-type vibratory motors are known to be used to provide motion in water to vessels, boats, submersible robots, launches [1, 2]. Their major drawbacks are inadequate traction power, increased hull hydrodynamic drag, course motion instability, - low speed.

The closest to the present invention, in terms of its technical nature and expected result, is a hydrodynamic fin vibrator, which consists of a drive, a transmission mechanism and two identical ribbed fins [3] (assumed as a prototype). In addition, the drive and transmission mechanism of the device are realized by known technical methods (for example, the drive may be electromagnetic, electric motor, electric stepping motor or hydraulic cylinder. The transmission mechanism may be designed as a crank or bevel mechanism, gear unit or a combination thereof.

Figure 1 shows the design of a fin as defined in the prototype, in the form of a thin-walled semi-cylinder gutter 1, the curved side of which is directed in the direction of travel from the longitudinal axis of the craft ("retraction"). The front, the rear and the horizontal edges are mounted in a frame 2, the front of which is attached to a shaft 3 (fin rotation axis), which in turn is connected to a vibrating actuator drive mechanism. The upper and lower edges of the fin half-cylinder are straight. The geometric parameters of the fin (length L, circumference B, radius R and thickness §) are chosen such that the trap maintains a stable straight line shape as its traverse towards the longitudinal axis of the craft "). in the opposite direction ("retraction"), the hydrodynamic force is influenced by the shape of the balance line of the longitudinal axis (the free end of the fin inclines towards the longitudinal axis of the craft).

The top view of the craft with two semi-cylindrical fins is shown in Figure 2. As the fins move away from the longitudinal axis of the craft ("in the upward direction"), they lose their stability and lean as shown in the diagram. At the maximum angle of retraction of the fins (end of the "shoot"), their movement stops momentarily. At this point, the hydrodynamic forces do not work and the fins are straightened by the internal elastic force that was generated at the point of overhang. The movement of the fins in the opposite direction (towards the longitudinal axis of the craft - "collapse") occurs in a straightened position. Thanks to the cyclic overhang of the fins, it is possible to significantly reduce the braking forces during "kickback" and thus increase the efficiency of the fin vibrator.

The prototype has the following disadvantages:

- the positioning of the fins at the rear of the craft reduces traction due to their presence in the ..hydrodynamic shade of the turbulent whirlpools of the water stream ', which reduces the rate of collapse and, consequently, traction;

- fins of this type, like other fins, cause insufficient traction due to flow loss - edges overflow and other losses, whereby traction also decreases due to the backflow characteristic of the prototype;

- increased hydrodynamic resistance of the hull, due to the positioning of the fins, since the arrangement of the fins, their attachment mechanisms and drive prevents the tail from forming in a streamlined form with minimal hydrodynamic resistance;

- Slight course motion (with respect to the vertical axis), which is explained by the fact that the fins produce a tractive force that is not applied to the center of gravity of the submarine, resulting in a destabilizing moment (misalignment of center of gravity or other reasons; deviations from the course that generate additional energy consumption for the movement are smaller in comparison with the single-jaw vibrator, but are still noticeable due to the tolerances of the technological processes of the fin production);

- low efficiency due to the aforementioned disadvantages, and in general low speed.

- In addition, it can be noted that the manufacture of fins in the form of a semi-cylinder and their anchoring at the rear is only successful in the case of a cylindrical body, thus limiting their applicability.

Fig. 3a shows the interaction of water streams as the fins 1 move in the direction of the longitudinal axis of the craft ("collapse"), choosing between two streams as an example of all streams. The fins 2 and 3 flush with the fixed housing at a constant velocity vi are perpendicular to the surface of the fins at each point in time. When they collide, the flow 4 at a velocity v? Is generated, which produces a traction force P. As the fins contract further, the counterflow 5 at a velocity v ₃ is produced which reduces the traction force P, which becomes inversely proportional to the angle between the fins. Finally, when the fins are parallel, the flows v ₃ and v ₃ become equal, but the traction force is zero. Thus, the emergence of backflow is one of the important reasons for the reduction in traction

5.

Purpose and substance of the invention

The object of the invention is to increase the operating efficiency of the fin vibrator, which is achieved by the fins being located at the front of the housing and being "pulling". The inside surfaces of the fins are fully coincident with the outer surface of the submersible craft and adhere to it during the folding phase. Above the fins, there is a triangular shape (wings) of load-bearing plates attached to the hull, which are made of thin and solid material and increase the efficiency of the vibrator of the fins.

In order to explain the working principles of the proposed fin vibrator and justify its advantages over the prototype, the following graphic material is attached to the description:

- Fig. 1 shows the design of a prototype fin in the form of a thin-walled semi-cylindrical chute (side view);

- Fig. 2 Shown is a schematic of a prototype vibrator with two semi-cylindrical spout fins at the rear of the housing.

- Fig. 3a, Fig. 3b and Fig. 3c. the interaction of the water flows with the fins defined in the prototype moving towards the axis of the craft (collapse) is shown;

- Fig. 4a, 4b. and Fig. 4c. shows an overview of the underwater craft hull with the proposed hydrodynamic fin vibrator.

Figure 4a shows a general view of the body 1 with four triangular flat wings 2 (two on each side) mounted inside a semi-cylindrical gutter fin 3. The fin rotation axes are positioned forward to the plane where the head passage to the center of the body ends. This allows the fin profile to be as simple as possible, technologically easy to make. The maximum angle of inclination of the fins is such that, in the fold, their upper and lower edges 4 (Fig. 3b) coincide with the leading edges 5 of the flat wings 2, enclosing a semi-enclosed space between the wings, fins and hull. The wings attached to the hull shall be equal to the length of the fins.

Evaluating the optimum shapes created by nature for floating objects (fish), it can be concluded that the cross-section is not circular but compressed (Fig. 3c). Therefore, in the axial axis of the prototype, the fins also do not have a circular section (half-cylinder), but the inside surfaces of the fins completely overlap with the outer surface of the underwater craft body and adhere to it during the folding phase. In order to guard against slope and maintain course stability, a wedge 6 (Fig. 1) is attached to the housing 1 with a pivoting corner 7 and a stabilizer 8 directed at the impact angle.

Movement is achieved by moving the fins 3, which, similar to the prototype in the slant, lose shape stability, reducing the resulting braking force. At the end of the turn, when the water fills the created semi-enclosed space between the wings 2, the housing 1 and the fins 3, the fins move in the opposite direction to the housing. The mass of water is expelled from the semi-enclosed space. In addition, due to the shape of the closed semicircle, the direction of the water displacement velocity is parallel to the axis of the cusp. The entire amount of water in the semi-enclosed space is squeezed out because there is virtually no flow of water over the fins. The upstream impedance seen on the prototype has been completely eliminated. The fins, along with the wings and housing, operate in a similar way to a piston pump, squeezing all the water in the semi-enclosed space "down to the last drop" and only in the opposite direction of motion. Therefore, at the same surface area of the fins, the pulling force P and the efficiency ;, coefficient significantly increase with the prototype and the proposed invention.

In view of these advantages, a positive economic effect from the practical realization of the proposed invention is expected.

Used information sources:

1. IJli> i <l> aHCKHH C., Bn6a Ή., ΉκγιπεΒπη B., KpyycMaa M., Menuui B. HccueñoBaHne pa6oTi> i nnaBHHKOBoro ΑΒίηκΗτεπζ rnņpo6HOHTa // JļnHaMiHaBiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHiHHiHiHiHHHiHiHiHiHiHiHiHiHiHiHiHHHiHiHiHiHiHiHiHHHiHiHHiHiHiHiHiHHHiHiHHiHiHiHiHiHiHiHiHiHiHiHiMi C6opHHK τρνγοΒ 16 CHMno3nyMa. - MocKBa-3BeHiiropoñ: PoccuucKaa AKaneMna HayK, 2009, c. 385-392.

2. Latvian patent LV 14054.

3. Latvian patent LV 14076 (prototype).

Claims (1)

Claim 1. A hydrodynamic fin moving vibrator, comprising a drive, a transmission mechanism and two identical fins in the form of a thin-walled semi-cylinder with a curved side facing outwards from the axis of the craft. but the concave side - inward, differs in that, in order to increase the traction power of the fin, to reduce the hydrodynamic drag of the hull, to increase course stability and efficiency: - the axes of rotation of the fins are located at the front of the hull and are towing, with the inner surfaces of the fins completely coinciding with the outer surface of the submersible craft's hull and in contact with the fins' folding phase, - the load-bearing plates in the form of a triangle (wings) are made above the fins at the top and bottom, made of a thin and solid material, but in slanting the upper and lower edges of the fins coincide with the flat edges of flat wings ai 'fin length.