A self-contained, waterproof, modular biomimetic oscillating fin

Abstract

This invention discloses an independently waterproof modular biomimetic oscillating fin, belonging to the field of underwater propulsion technology. It includes a base sealing assembly with a static waterproof structure, a DC motor fixed within the base sealing assembly, a swing arm assembly operatively connected to the motor output shaft of the DC motor, and a dynamic waterproof structure disposed between the base sealing assembly and the swing arm assembly. The working end of the motor output shaft is inclined; when the output shaft rotates, the swing arm reciprocates through the transmission action of a limiting post, thereby driving the fin-like surface to generate propulsion. Simultaneously, this invention provides a simple method for manufacturing a waterproof membrane, enabling rapid fabrication of the membrane required for the dynamic waterproof structure. This invention, employing a modular design, an efficient propulsion scheme, and a simple and flexible waterproofing solution, effectively overcomes the limitations of traditional underwater biomimetic oscillating fins, which suffer from complex assembly, limited waterproofing solutions, and high costs. It is of great significance for promoting the development of underwater propulsion technology.

Description

Technical Field

[0001] This invention belongs to the field of underwater propulsion technology, specifically relating to an independent, waterproof, modular bionic oscillating fin. Technical Background

[0002] As a key module in underwater biomimetic design, the oscillating mechanism generates propulsion through periodic oscillations. When installed on underwater robots, it enables them to possess flexible and low-noise motion characteristics. However, the underwater environment poses challenges to the sealing performance and power transmission efficiency of the oscillating mechanism.

[0003] Traditional underwater oscillation mechanisms typically use servo motors for reciprocating motion, but these have drawbacks such as limited oscillation frequency, making it difficult to meet the demands for high maneuverability. During long-term underwater operation, insufficient waterproofing design can lead to corrosion or water leakage damage to internal components, affecting their reliability and service life. Although some studies have adopted dedicated waterproof motors as a drive solution, their high cost and complex structure limit their large-scale application.

[0004] Therefore, there is an urgent need for a swing mechanism that combines modular design, low cost, and excellent waterproof performance to overcome the limitations of traditional underwater swing mechanisms, which is of great significance for promoting the development of underwater propulsion technology. Summary of the Invention

[0005] To address the problems in the prior art, this invention proposes an independent, waterproof, modular biomimetic oscillating fin; the oscillation mechanism enables the fin surface to oscillate, and it can be installed as an independent oscillation drive module on an underwater robot; combined with the waterproofing scheme of the oscillation mechanism, efficient and low-cost waterproofing can be achieved.

[0006] The technical solution adopted in this invention is as follows:

[0007] In a first aspect, the present invention proposes an independent waterproof modular bionic swing fin, comprising a base sealing assembly with a static waterproof structure, a DC motor fixed in the base sealing assembly, a swing arm assembly operatively connected to the motor output shaft of the DC motor, and a dynamic waterproof structure disposed between the base sealing assembly and the swing arm assembly; the working end of the motor output shaft is arranged at an angle.

[0008] The base sealing assembly includes a base and a waterproof sleeve, the waterproof sleeve being fixed to the base; the swing arm assembly includes a swing arm and a fin-shaped surface fixed to the swing arm, the two ends of the swing arm being connected to the waterproof sleeve through a bearing assembly, a pair of limiting posts being symmetrically embedded on the inner side of the swing arm, the limiting posts being located on both sides of the inclined motor output shaft and having a small gap reserved between them and the surface of the motor output shaft, so that the rotational motion of the motor output shaft drives the swing arm to swing back and forth through the limiting posts, thereby driving the fin-shaped surface to generate propulsion force;

[0009] The dynamic waterproof structure is a flexible waterproof membrane with an opening at the lower edge that is fitted over the outside of the swing arm. The opening of the flexible waterproof membrane is clamped and sealed by a static waterproof structure between the waterproof sleeve and the base.

[0010] As a preferred embodiment of the present invention, the limiting post is a carbon column made of carbon fiber, and the carbon column is embedded in the carbon column mounting groove of the swing arm.

[0011] As a preferred embodiment of the present invention, the bearing assembly includes a thrust ball bearing, wherein the inner side of the thrust ball bearing is embedded in the bearing mounting inner groove of the rocker arm, and the outer side is embedded in the bearing mounting outer groove of the waterproof sleeve.

[0012] As a preferred embodiment of the present invention, the static waterproof structure includes a base mating sealing groove located at the edge of the base and a sleeve mating sealing groove located at the edge of the waterproof sleeve. Both sealing grooves are provided with silicone waterproof strips, and a double sealing interface is formed by the concave-convex fit.

[0013] As a preferred embodiment of the present invention, the fin-shaped surface is fixed to the upper surface of the swing arm by screws, and the swing arm is provided with a swing arm positioning protrusion, and the fin-shaped surface is provided with a positioning hole corresponding to the swing arm positioning protrusion.

[0014] As a preferred embodiment of the present invention, the swing arm is provided with a swing arm waterproof washer groove at the screw mounting position, and a silicone waterproof washer is provided in the groove.

[0015] As a preferred embodiment of the present invention, the base is provided with a base data cable groove, through which the data cable of the DC motor is led out, and the gap between the data cable and the base data cable groove is filled with waterproof glue.

[0016] As a preferred embodiment of the present invention, the flexible waterproof film is made of TPU material, and its upper side is provided with waterproof film fixing holes corresponding to the screw holes of the fin-shaped surface and the swing arm, and the flexible waterproof film is clamped between the fin-shaped surface and the swing arm.

[0017] As a preferred embodiment of the present invention, the flexible waterproof film is made by bonding two single-piece TPU films along the edges using a heat-sealing process, while retaining a bottom opening.

[0018] Secondly, the present invention proposes a method for manufacturing a waterproof membrane, which is applied to the above-mentioned independently waterproof modular bionic oscillating fin, and uses the waterproof membrane as a dynamic waterproof structure in the bionic oscillating fin.

[0019] The production method includes the following steps:

[0020] (1) Take two single-piece waterproof films made of TPU material, and make waterproof film fixing holes on the two films respectively, corresponding to the screw hole positions of the fin surface and the swing arm;

[0021] (2) Align and attach the two single waterproof films and heat them along the edges to above the melting point of the TPU material so that the film edges melt and bond. At the same time, apply pressure to promote the integrity of the bond. Leave the bottom straight edge unheated to form an opening on the bottom side.

[0022] (3) After cooling, a tensile test is performed on the bonding edge to verify the bonding strength. Once the requirements are met, the lower opening is opened and the sleeve is placed outside the swing arm.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention provides a swing mechanism that combines the motor output shaft with the limit post with the inclined working surface to efficiently convert the unidirectional rotation of the DC motor into the sinusoidal reciprocating swing of the swing arm. This not only overcomes the bottleneck of the frequency limitation of the traditional servo motor, but also significantly improves the transmission efficiency and motion stability. Furthermore, through the modular fin surface and base design, it can be used as an independent drive module to flexibly adapt to different underwater robots.

[0025] (2) The swing mechanism of the present invention has a dual waterproof structure, and combines the static waterproofing of the base sealing component with the dynamic sealing of the flexible waterproof membrane. While ensuring reliability, the waterproofing cost is greatly reduced. The simple heat sealing process of the waterproof membrane further improves the economy and maintainability, and is easy to disassemble and assemble, making the waterproofing solution more flexible.

[0026] (3) The entire solution of the present invention achieves a compact layout through a highly integrated structural design, which enables the swing mechanism to be quickly installed and deployed as an independent drive module, providing a high-performance, low-cost and easy-to-maintain solution for underwater biomimetic propulsion technology. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the swing mechanism;

[0028] Figure 2 This is an exploded view of the swing mechanism.

[0029] Figure 3 This is a schematic diagram of the base structure of the swing mechanism;

[0030] Figure 4 This is a schematic diagram of the waterproof ferrule structure of the swing mechanism;

[0031] Figure 5 This is a cross-sectional schematic diagram of a swing mechanism with a waterproof membrane;

[0032] Figure 6 This is a simplified processing method diagram for waterproof films;

[0033] In the diagram, 1-fin-shaped surface, 2-swing arm, 3-waterproof sleeve, 4-base, 5-DC motor, 6-motor output shaft, 7-carbon column, 8-carbon column mounting groove, 9-bearing mounting inner groove, 10-swing arm waterproof washer groove, 11-swing arm positioning protrusion, 12-bearing mounting outer groove, 13-thrust ball bearing, 14-base mating sealing groove, 15-base data cable groove, 16-base mounting hole, 17-motor mounting hole, 18-sleeve mating sealing groove, 19-sleeve mounting hole, 20-cylindrical nut fixing groove, 21-flexible waterproof membrane, 22-waterproof strip, 23-single-piece waterproof membrane, 24-waterproof membrane fixing hole. Detailed Implementation

[0034] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0035] This invention proposes an independently waterproof modular biomimetic oscillating fin, which mainly includes an oscillating mechanism and a double waterproof structure, significantly reducing waterproofing costs while ensuring waterproofing reliability.

[0036] Combination Figure 1 and Figure 2 As shown in the schematic diagram and exploded view of the swing mechanism proposed in this invention, the swing mechanism includes a base sealing assembly with a static waterproof structure, a DC motor 5 fixed in the base sealing assembly, a swing arm assembly operatively connected to the motor output shaft 6 of the DC motor 5, and a dynamic waterproof structure disposed between the base sealing assembly and the swing arm assembly; the working end of the motor output shaft 6 is arranged at an angle to interact with the limiting element of the swing arm assembly.

[0037] The base sealing assembly includes a base 4 and a waterproof sleeve 3, the waterproof sleeve 3 being fixed to the base 4; the swing arm assembly includes a swing arm 2 and a fin-shaped surface 1 fixed to the swing arm 2, the two ends of the swing arm 2 being connected to the waterproof sleeve 3 through bearing assemblies, a pair of limiting posts being symmetrically embedded on the inner side of the swing arm 2, the limiting posts being located on both sides of the inclined motor output shaft 6 and having a small gap, for example 0.1mm-1mm, between them and the surface of the motor output shaft, so that the rotational movement of the motor output shaft 6 drives the swing arm 2 to swing back and forth through the limiting posts, thereby driving the fin-shaped surface 1 to generate propulsion force.

[0038] Combination Figure 3 and Figure 4As shown, key functional holes are provided on the base 4 and the waterproof sleeve 3 to achieve precision assembly and reliable sealing. The base 4 has base mounting holes 16 machined on it, evenly distributed on the side flange, for connecting to the waterproof sleeve 3 with screws. Simultaneously, a motor mounting hole 17 is provided at the bottom of the base's inner cavity for fixing a DC motor 5. The waterproof sleeve 3 has corresponding sleeve mounting holes 19, coaxially arranged with the base mounting holes 16, forming a through connection channel. This ensures that screws can penetrate both and cooperate with the cylindrical nut fixing groove 20 inside the base for locking. These holes are machined using high-precision coordinates, ensuring not only modularity and ease of assembly but also a stable mechanical foundation for the static waterproof structure.

[0039] The fin-shaped surface 1 is fixed to the upper surface of the swing arm 2 by screws, and the swing arm 2 is provided with a swing arm positioning protrusion 11. The fin-shaped surface 1 is provided with a positioning hole corresponding to the swing arm positioning protrusion. High-precision positioning is achieved through the swing arm positioning protrusion 11 and the positioning hole. The bearing assembly is preferably a thrust ball bearing 13. The swing arm 2 and the waterproof sleeve 3 are connected by clamping the thrust ball bearings 13 on both sides. The inner side of the thrust ball bearing 13 is embedded in the bearing mounting inner groove 9 of the swing arm, and the outer side is embedded in the bearing mounting outer groove 12 of the waterproof sleeve, forming a stable rotating pair. It is fixed by the clamping action of the swing arm 2. The three mounting holes between the waterproof sleeve 3, the thrust ball bearing 13 and the swing arm 2 are hinged by locking screws. The inner surface of the waterproof sleeve 3 is provided with a groove to avoid axial deviation due to the thickness of the locking nut during the swing of the swing arm. The waterproof sleeve 3 is connected to the base 4 by screws. The inner wall of the base 4 has four cylindrical nut fixing slots 20. After inserting the cylindrical nuts, the screws can be used to penetrate the mounting holes 16 and 19 of the base and fix them to the cylindrical nuts.

[0040] The DC motor 5 is fixed to the motor mounting hole 17 of the base 4 by bottom screws; the motor output shaft 6 is connected to the DC motor 5 by screws. The motor output shaft 6 includes a flat connecting part and an inclined working end with an inclination angle of 20-50°, which is 35° in this embodiment; the limiting post is preferably a carbon column 7 made of carbon fiber. The end of the motor output shaft 6 is located between two carbon columns 7, with a small gap reserved between them and their surfaces. The outer diameter of the two carbon columns 7 is consistent with the carbon column mounting groove 8 on the swing arm, and they can pass through the carbon column mounting groove 8 and be embedded in the swing arm 2. The carbon columns 7 are made of carbon fiber. In this embodiment, after the carbon column is installed, it maintains a gap of 0.17mm with the surface of the motor output shaft 6.

[0041] For ease of description, the motion principle of the swing mechanism will be... Figure 1The state shown is called the zero-phase state. When the DC motor 5 starts to rotate unidirectionally in the zero-phase state, it drives the motor output shaft 6 to rotate. The motor output shaft 6 crosses the reserved small gap and is tangent to the surface of one of the carbon pillars 7. Through the limiting effect of the carbon pillar 7, it drives the swing arm 2 to swing back and forth, causing the fin surface 1 fixed on the swing arm 2 to swing back and forth. After the DC motor rotates 180°, it will cross the reserved small gap and be tangent to the other carbon pillar 7. At this time, the fin surface 1 continues to swing back and forth. During one rotation of the DC motor in one direction, the fin surface completes one cycle of sinusoidal oscillation. The oscillation frequency depends on the rotation speed of the DC motor. It should be noted that, due to the inclined working surface design of the motor output shaft 6 in this invention, the contact point position between it and the carbon column 7 changes at a constant speed during rotation. When the output shaft rotates at a constant angular velocity ω, the tangent point between its working surface and the carbon column moves at a constant speed along the axial direction. Under the tangential action between the working surface of the output shaft and the carbon column, the rotational motion of the output shaft is converted into the angular displacement of the swing arm. Since the inclination angle of the working surface is constant, the displacement of the tangent point is linearly related to the rotation angle of the output shaft, and the angular acceleration of the swing arm is differentially related to the displacement of the tangent point. Therefore, the change of angular displacement with time conforms to the characteristics of a sine function.

[0042] In one specific embodiment of the present invention, the fin surface 1 can change its shape as needed, thereby flexibly changing the shape of the oscillating fin to adapt to different hydrodynamic environments and operational requirements. For example, a high aspect ratio airfoil can be used to improve efficiency for low-speed observation tasks, or a low aspect ratio airfoil can be used to enhance maneuverability for high maneuverability requirements.

[0043] In one specific embodiment of the present invention, the base 4 can change its bottom shape as needed, thereby quickly integrating the entire swing mechanism as a standardized, independent drive module into various underwater robot platforms.

[0044] To achieve waterproofing of the aforementioned swing mechanism, the present invention provides a bottom static waterproofing structure and a top dynamic waterproofing structure.

[0045] like Figure 3 and Figure 4 The static waterproof structure is shown to include a base-fitting sealing groove 14 located at the edge of the base 4 and a sleeve-fitting sealing groove 18 located at the edge of the waterproof sleeve 3. Both sealing grooves contain silicone waterproof strips 22, which form a double-sealing interface through a concave-convex fit. The principle is that the waterproof strips within the matching waterproof grooves are compressed to achieve a static seal at the bottom of the swing mechanism. The base 4 also has a base data cable groove 15, through which the data cable of the DC motor 5 is led out, and the gap between the data cable and the base data cable groove is filled with waterproof adhesive.

[0046] In one specific embodiment of the present invention, one end of the data line leading out from the DC motor 5 is connected to the DC motor, and the other end can be connected to the motor drive of the underwater robot through a waterproof aviation connector. The motor drive can measure the output power of the swing mechanism by connecting to a power detection module.

[0047] like Figure 5 The diagram shown is a cross-sectional view of a swing mechanism with a waterproof membrane. Figure 5 As shown in (a), the top dynamic waterproof structure is a flexible waterproof membrane 21 with an open lower edge, fitted over the outside of the swing arm 2. The flexible waterproof membrane 21 is in a pleated state (not shown in the figure), and its opening is clamped and sealed by a static waterproof structure between the waterproof sleeve 3 and the base 4. The principle is that the waterproof membrane with the bottom opening can isolate the liquid outside the swing arm 2, and the opening can be clamped in the waterproof groove of the bottom static waterproof structure, thereby achieving dynamic waterproofing of the top of the swing mechanism. Figure 5 (b) in the middle is Figure 5 In the enlarged view of (a) in the figure, it can be seen that silicone waterproof strips 22 are provided in the two sealing grooves of the static waterproof structure between the waterproof sleeve 3 and the base 4, and a double sealing interface is formed by the concave and convex fit. The opening of the flexible waterproof membrane is clamped and sealed by the static waterproof structure.

[0048] In one specific embodiment of the present invention, the flexible waterproof membrane has two screw mounting holes on its upper side, the size and position of which are consistent with the screw holes on the fin-shaped surface 1 and the swing arm 2, and its lower side is open; during the installation of the waterproof membrane on the upper side, the fin-shaped surface 1 and the swing arm 2 clamp the waterproof membrane between them, and the fixing screw between them passes through the fixing hole 24 of the waterproof membrane. The swing arm 2 has a swing arm waterproof washer groove 10 at the screw mounting position, in which a silicone waterproof washer is provided to block the gap between the screw and its threaded hole; during the installation of the waterproof membrane on the lower side, when the ferrule mating sealing groove 18 matches the groove on the base mating sealing groove 14, it clamps the waterproof membrane between them. Since both the protrusion and the groove are provided with silicone waterproof strips 22, the waterproof membrane can fit tightly with the protrusion and the groove to achieve a waterproof effect; during the installation of the waterproof membrane, sufficient slack should be left, that is, the length of the waterproof membrane should be greater than the distance between the base mating sealing groove 14 and the top of the swing arm 2, to provide the swing space required for the swing arm 2.

[0049] Based on the above, the present invention also provides a simple method for manufacturing a waterproof film, which involves bonding two single-piece TPU films 23 along their edges using a heat-sealing process, leaving an opening at the bottom. Figure 6 The diagram shows a simplified processing method for waterproof membranes. The specific steps are as follows:

[0050] Step 1. Take two single-piece waterproof films 23 made of TPU material, both of the same size, and make waterproof film fixing holes 24 on the two films respectively. The size and position are consistent with the screw holes on the fin surface 1 and the swing arm 2.

[0051] Step 2. Based on the thermoplasticity of TPU material, after bonding and aligning the two single-piece waterproof films, follow the... Figure 6 Heating is applied at the point indicated by the dashed line. When the single waterproof film is heated to above its melting point and melts, the two pieces will bond together along the dashed line. Applying pressure will promote the bonding of the two waterproof films along the dashed line.

[0052] Step 3. Stop heating and wait for the waterproof film to cool. Apply tensile force to test the adhesion strength at the dotted line. If it meets the requirements, then... Figure 6 The lower opening shown by the solid line is opened and fitted onto the outside of the swing arm 2, and waterproofed according to the top dynamic waterproof structure.

[0053] The above embodiments are merely illustrative of several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A modular, waterproof, biomimetic oscillating fish fin, characterized in that, It includes a base sealing assembly with a static waterproof structure, a DC motor (5) fixed in the base sealing assembly, a swing arm assembly operatively connected to the motor output shaft (6) of the DC motor (5), and a dynamic waterproof structure disposed between the base sealing assembly and the swing arm assembly; the working end of the motor output shaft (6) is arranged at an angle. The base sealing assembly includes a base (4) and a waterproof sleeve (3), the waterproof sleeve (3) being fixed on the base (4); the swing arm assembly includes a swing arm (2) and a fin surface (1) fixed on the swing arm (2), the two ends of the swing arm (2) being connected to the waterproof sleeve (3) through a bearing assembly, a pair of limiting posts being symmetrically embedded on the inner side of the swing arm (2), the limiting posts being located on both sides of the inclined motor output shaft (6) and having a small gap reserved between them and the surface of the motor output shaft, so that the rotational movement of the motor output shaft (6) drives the swing arm (2) to swing back and forth through the limiting posts, thereby driving the fin surface (1) to generate propulsion force; The dynamic waterproof structure is a flexible waterproof membrane with an opening at the lower edge and sleeved on the outside of the swing arm (2). The opening of the flexible waterproof membrane is clamped and sealed by the static waterproof structure between the waterproof sleeve (3) and the base (4). The flexible waterproof membrane is made of TPU material and has a waterproof membrane fixing hole (24) on its upper side corresponding to the screw holes of the fin surface (1) and the swing arm (2). The flexible waterproof membrane is clamped between the fin surface (1) and the swing arm (2).

2. The independently waterproof modular bionic oscillating fin according to claim 1, characterized in that, The limiting post is a carbon column (7) made of carbon fiber, and the carbon column (7) is embedded in the carbon column mounting groove (8) of the swing arm (2).

3. The independently waterproof modular bionic oscillating fin according to claim 1, characterized in that, The bearing assembly includes a thrust ball bearing (13), with the inner side of the thrust ball bearing (13) embedded in the bearing mounting inner groove (9) of the rocker arm (2) and the outer side embedded in the bearing mounting outer groove (12) of the waterproof sleeve (3).

4. The independently waterproof modular bionic oscillating fin according to claim 1, characterized in that, The static waterproof structure includes a base fitting sealing groove (14) located at the edge of the base (4) and a sleeve fitting sealing groove (18) located at the edge of the waterproof sleeve (3). Both sealing grooves are provided with silicone waterproof strips (22), and a double sealing interface is formed by the concave-convex fit.

5. The independently waterproof modular biomimetic oscillating fin according to claim 1, characterized in that, The fin-shaped surface (1) is fixed to the upper surface of the swing arm (2) by screws, and the swing arm (2) is provided with a swing arm positioning protrusion (11), and the fin-shaped surface (1) is provided with a positioning hole corresponding to the swing arm positioning protrusion.

6. The independently waterproof modular biomimetic oscillating fin according to claim 5, characterized in that, The swing arm (2) has a swing arm waterproof washer groove (10) at the screw installation position, and a silicone waterproof washer is installed in the groove.

7. The independently waterproof modular bionic oscillating fin according to claim 1, characterized in that, The base (4) is provided with a base data cable groove (15). The data cable of the DC motor (5) is led out through the base data cable groove, and the gap between the data cable and the base data cable groove is filled with waterproof glue.

8. The independently waterproof modular bionic oscillating fin according to claim 1, characterized in that, The flexible waterproof film is made by bonding two single TPU films (23) along the edges using a heat-sealing process, leaving an opening at the bottom.

9. A method for manufacturing a waterproof membrane, applied to the independently waterproof modular biomimetic oscillating fish fin according to any one of claims 1-8, characterized in that, Using a waterproof membrane as a dynamic waterproof structure in a biomimetic undulating fish fin; The production method includes the following steps: (1) Take two single-piece waterproof films made of TPU material, and make waterproof film fixing holes on the two films respectively, corresponding to the screw hole positions of the fin surface and the swing arm; (2) Align and attach the two single waterproof films and heat them along the edges to above the melting point of the TPU material so that the film edges melt and bond. At the same time, apply pressure to promote the integrity of the bond. Leave the bottom straight edge unheated to form an opening on the bottom side. (3) After cooling, a tensile test is performed on the bonding edge to verify the bonding strength. Once the requirements are met, the lower opening is opened and the sleeve is placed outside the swing arm.

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