Shaftless rim-embedded pressure-compensated propeller and bearingless support structure

Abstract

The application discloses a shaftless rim built-in pressure compensation propeller and bearing-free support structure, comprising a static support, a rotating duct and a propeller. A closed cavity is formed in the static support, and an elastic sealing compensation body capable of elastically deforming is arranged in the cavity, which is used for compensating the cavity volume change caused by thermal expansion and contraction of the medium and shell structure deformation. The rotating duct and the static support are matched by a taper surface and a taper hole to form a gap, and when working, external water flow enters to form a water film, thereby realizing bearing-free support, lubrication and cooling. The application is compatible with inner rotor and outer rotor structures, is suitable for gas or liquid medium, has compact structure and reliable sealing, and can be widely applied to underwater robots, ship auxiliary propulsion and underwater operation equipment.

Description

Technical Field

[0001] This invention relates to the field of underwater propulsion equipment technology, specifically to a shaftless rim propeller, and more particularly to a shaftless rim propeller with a built-in elastic pressure compensation structure and bearingless support using a conical water film. Background Technology

[0002] Shaftless rim thrusters offer advantages such as compact structure, high propulsion efficiency, and anti-entanglement properties, making them widely used in small to medium-power underwater equipment, including underwater robots, ship auxiliary propulsion, and underwater work equipment. Shaftless rim thrusters typically employ a closed-cavity structure, with the cavity filled with a gas or liquid medium, relying on the shell and the external water environment for heat dissipation.

[0003] During actual operation, the medium inside the cavity expands and contracts due to the heat generated by the motor; in deep water environments, external water pressure can also cause slight deformation of the propeller casing structure, further altering the cavity volume. These factors collectively cause continuous pressure fluctuations within the cavity, directly affecting the reliability of the sealing system.

[0004] In shallow water conditions, even without full load, prolonged continuous operation will cause the medium temperature to rise slowly, generating a sustained internal positive pressure. Long-term pressure fluctuations subject the seals to repeated alternating loads, gradually leading to fatigue, deformation, and microcracks, resulting in a gradual decline in sealing performance and ultimately causing leaks and water ingress. Under full load or frequent start-stop conditions, the thermal expansion of the medium is even more dramatic, causing a rapid increase in internal positive pressure, which can easily force open the seal, leading to oil leaks or water infiltration.

[0005] In deep-water conditions, the external water pressure increases significantly, and the changes in cavity volume caused by shell deformation become more pronounced. Negative pressure is easily formed inside the cavity, and high-pressure water from the outside will be drawn into the cavity under the action of the pressure difference, directly causing serious failures such as motor short circuits and burnout.

[0006] Traditional pressure compensation devices mostly adopt an external structure, protruding from the outside of the machine. This not only increases the size but also makes them prone to collisions and entanglement, failing to meet the requirements of small and medium-power shaftless rim propellers for miniaturization, simplicity, and high reliability. Furthermore, traditional shaftless rim propellers often use rolling bearings for support, which suffer from wear, jamming, and limited lifespan. Currently, the industry lacks a compact, integrated pressure balancing and support solution that can operate long-term in shallow water, safely in deep water, and stably under all working conditions. Summary of the Invention

[0007] Technical issues

[0008] This invention addresses the problems of cavity pressure fluctuation, easy seal failure, poor reliability of external compensation devices, and easy bearing wear in existing shaftless rim thrusters. It provides a shaftless rim thruster with built-in pressure compensation and a bearingless support structure, which achieves built-in pressure balance and bearingless water film support. The whole machine has a compact structure, reliable sealing, long service life, and wide applicability.

[0009] Technical solution

[0010] A shaftless rim-mounted pressure-compensated thruster includes a stationary support (1), a rotating duct (2), and a propeller (5). The stationary support (1) has a closed cavity (3) inside; the closed cavity (3) contains an elastically deformable sealed elastic compensator (4) to compensate for volume changes caused by thermal expansion and contraction of the medium and changes in cavity volume caused by deformation of the shell structure due to external water pressure. The stationary support (1) is used to fix the stator (6) of the thruster. The rotating duct (2) and the stationary support (1) form a bearingless support structure through a conical fit: the mating surfaces of the rotating duct (2) and the stationary support (1) are respectively provided with a conical surface and a conical hole, forming a gap (7) between the conical surface and the conical hole. During operation, external water flows into the gap to form a water film, achieving support, lubrication, and cooling.

[0011] Furthermore, the enclosed cavity (3) is statically sealed and isolated, and is not in contact with external water flow. The propeller can adopt an inner rotor shaftless rim structure or an outer rotor shaftless rim structure. The enclosed cavity (3) can be filled with gas or insulating liquid medium. The sealed elastic compensator (4) can be filled with dry air or inert gas to form an independent sealed structure. The size and distribution of the gaps (7) can be optimized according to the working conditions to ensure the stability of the water film. This invention does not require an additional external pressure compensation mechanism and has a smooth and simple appearance.

[0012] Beneficial effects

[0013] The built-in sealed elastic compensator (4) automatically compensates for volume changes caused by changes in medium temperature and volume changes caused by structural deformation due to external water pressure, keeping the pressure inside the cavity (3) stable and ensuring the reliability of the sealing system.

[0014] The external water pressure is borne by the static support (1) as a whole, and the elastic compensator (4) does not directly bear the external water pressure load, so it is stable in operation and has a long service life.

[0015] The machine has no external pressure compensation mechanism, a smooth and simple appearance, and features anti-collision and anti-weed entanglement characteristics.

[0016] It is compatible with both internal and external rotor structures, suitable for gaseous or liquid media, and has strong versatility.

[0017] The conical water film bearingless support structure eliminates rolling bearings, achieving non-contact, low-wear operation. It uses external water as a lubricating medium, resulting in low maintenance costs. At the same time, the forced convection cooling of the water flow provides high heat dissipation efficiency.

[0018] Pressure compensation structures and bearingless support structures can be used in combination or independently, with a wide range of applications. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of the overall structure of the propulsion device of the present invention.

[0020] Figure 2 for Figure 1 A magnified view of part I in the middle shows the gap between the conical hole and the conical surface.

[0021] Figure label:

[0022] 1—Static support

[0023] 2—Rotating Duct

[0024] 3—Closed cavity

[0025] 4—Closed elastic compensator

[0026] 5—Propeller

[0027] 6-Stator

[0028] 7—Gap Detailed Implementation

[0029] The present invention will be further described in detail below with reference to specific embodiments.

[0030] Example 1: Basic Structure

[0031] A shaftless rim-mounted pressure-compensated propeller includes a stationary support 1, a rotating duct 2, and a propeller 5.

[0032] The stationary support 1 is an assembled structure, including a housing, end caps, stator isolation sleeves, and a conical sleeve, which are fixedly connected to form a whole. The stationary support 1 is provided with a sealing groove and a sealing structure to achieve static sealing isolation between the closed cavity 3 and the external water flow. The stator 6 is fixed inside the stationary support 1 and arranged around the rotating duct 2.

[0033] The enclosed cavity 3 is formed inside the stationary support 1 and is filled with insulating cooling oil (or other media). The sealed elastic compensator 4 is a sealed cavity structure that can be elastically deformed and is filled with dry air (at normal pressure). It is completely housed inside the cavity 3 and does not come into contact with external water flow.

[0034] The rotating duct 2 and the stationary support 1 have conical surfaces and conical holes on their mating surfaces (i.e., one has a conical surface and the other has a conical hole), forming a gap 7 after assembly. The gap size can be optimized according to the working conditions to ensure water film stability. During operation, external water flows into the gap to form a water film, achieving non-contact support, lubrication, and cooling between the rotating duct 2 and the stationary support 1.

[0035] When the temperature of the medium changes or the shell is deformed by external water pressure, the sealed elastic compensator 4 is passively compressed or expanded to compensate for the volume change and maintain the pressure stability inside the cavity 3.

[0036] Example 2: Internal Rotor Structure

[0037] The propeller adopts an internal rotor shaftless rim structure. The rotating duct 2 is located inside the stator 6. The propeller 5 rotates synchronously with the rotating duct 2. The stationary support 1 is located on the outside and fixes the stator 6. The enclosed cavity 3 is formed inside the stationary support 1.

[0038] Example 3: External rotor structure

[0039] The thruster adopts an external rotor shaftless rim structure. The rotating duct 2 is located outside the stator 6. The propeller 5 rotates synchronously with the rotating duct 2. The stationary support 1 is located inside and fixes the stator 6. The enclosed cavity 3 is formed inside the stationary support 1.

[0040] Example 4: Gas Medium

[0041] The enclosed cavity 3 is filled with a gaseous medium (such as dry air or nitrogen) and relies on the shell for natural heat dissipation. The sealed elastic compensator 4 can also compensate for volume changes caused by the thermal expansion and contraction of the gas.

[0042] Example 5: Liquid Medium

[0043] The enclosed cavity 3 is filled with insulating cooling oil to improve heat dissipation efficiency.

[0044] Example 6: No external compensation mechanism for the whole machine

[0045] This invention does not require additional external bladders, pistons, or other compensation structures, and has no protruding parts.

[0046] Example 7: Bearingless support for standalone application

[0047] The conical water film bearingless support structure can be applied alone to shaftless rim propellers. Without the installation of a sealed elastic compensator 4, it can still achieve the support effect of bearingless, low wear, self-lubrication, and self-cooling.

Claims

1. A shaftless rim-mounted pressure-compensated propeller, comprising a stationary support (1), a rotating duct (2), and a propeller (5), characterized in that: The static support (1) has a closed cavity (3) inside; The closed cavity (3) is provided with a tightly deformable closed elastic compensator (4) to compensate for the volume change caused by thermal expansion and contraction of the medium and the cavity volume change caused by the deformation of the shell structure due to external water pressure. The stationary support (1) is used to fix the stator (6) of the thruster; The rotating duct (2) and the stationary support (1) form a bearingless support structure through a conical surface fit: the rotating duct (2) and the stationary support (1) are respectively provided with a conical surface and a conical hole, and a gap (7) is formed between the conical surface and the conical hole. When working, external water flows into the gap to form a water film, which realizes support, lubrication and cooling.

2. The thruster according to claim 1, characterized in that: The enclosed cavity (3) is statically sealed and isolated, and is not in contact with external water flow.

3. The thruster according to claim 1, characterized in that: The propeller is an inner rotor shaftless rim propeller, and the rotating duct (2) is located inside the stator (6); or the propeller is an outer rotor shaftless rim propeller, and the rotating duct (2) is located outside the stator (6).

4. The thruster according to claim 1, characterized in that: The enclosed cavity (3) is filled with gas or insulating liquid medium.

5. The thruster according to claim 1, characterized in that: The thruster does not have an additional external pressure compensation mechanism.

6. The thruster according to claim 1, characterized in that: The sealed elastic compensator (4) is filled with dry air or inert gas.

7. A bearingless support structure for a shaftless rim propeller, characterized in that: The rotating duct (2) and the stationary support (1) are coaxially fitted together through their mating surfaces. The mating surfaces are respectively provided with a conical surface and a conical hole, and a gap (7) is formed between the conical surface and the conical hole. When working, external water flows into the gap to form a water film, achieving bearingless support, lubrication and cooling.

8. The bearingless support structure according to claim 7, characterized in that: The bearingless support structure is applied to an inner rotor shaftless rim propeller or an outer rotor shaftless rim propeller.

9. The bearingless support structure according to claim 7, characterized in that: The bearingless support structure can be used in conjunction with the sealed elastic compensator of the propeller according to any one of claims 1 to 6.

10. An underwater robot, a ship auxiliary propulsion device, or underwater operation equipment, characterized in that: It includes the thruster as described in any one of claims 1 to 6.

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