Low-vibration underwater propulsion motor and underwater propeller

Abstract

The application discloses a low-vibration underwater propelling motor and underwater propeller. The low-vibration underwater propelling motor comprises a shell, a stator, a rotor and an elastic pipe; the stator and the rotor are sealed in the shell; the elastic pipe is arranged outside the shell and communicates with an inner cavity of the shell; the inner cavity of the shell and the elastic pipe are filled with insulating medium oil; the two ends of the rotor are connected with the shell through sliding bearings respectively, and the extension of the rotor is matched with the shell through a dynamic sealing structure; gaps between the inside of the sliding bearings and the rotor communicate with the inner cavity of the shell, so that the insulating medium oil can form a pressure-bearing oil film in the gaps at least at the contact interface of the sliding bearings and the rotor. The low-vibration underwater propelling motor has the advantages of low vibration, low noise and the like, and can be stably operated in deep water for a long time.

Description

Technical Field

[0001] The present application relates to an underwater propeller, and in particular to a low-vibration underwater propulsion motor and an underwater propeller. Background Art

[0002] As the core power component of deep-sea equipment, the performance of underwater propulsion motors directly affects the maneuverability, stealth and operating depth of underwater vehicles. Existing underwater motors usually use a rigid stator and rotor structure. The mechanical vibration caused by electromagnetic excitation will be directly transmitted to the external fluid medium through the shell, resulting in significant hydrodynamic noise during operation. Although the vibration and noise of the motor can be reduced to a certain extent by improving the processing accuracy of the internal components of the motor and performing high-level dynamic balancing on the rotor, the cost is high and the degree of vibration and noise suppression is limited. At the same time, the pressure-resistant shell design of existing motors mostly relies on the thickening of a single material or a simple sealing structure. In deep-water high-pressure environments, it is easy to cause deformation or even leakage due to stress concentration, resulting in limited overall pressure resistance. The typical diving depth is generally below 1,000 meters. Summary of the Invention

[0003] The main purpose of this application is to provide a low-vibration underwater propulsion motor and underwater propeller to overcome the defects of the prior art.

[0004] In order to achieve the above-mentioned purpose of the invention, this application provides the following technical solutions.

[0005] One aspect of the present application provides a low-vibration underwater propulsion motor, comprising a stator and a rotor sealed in a housing, wherein the stator is fixedly connected to the housing, the rotor is rotatably mounted in the housing, and the stator is sleeved on the rotor. The low-vibration underwater propulsion motor further comprises:

[0006] At least two sliding bearings are fixedly disposed in the housing, and at least two sliding bearings are spaced apart at both ends of the stator along the axial direction of the stator, and the rotor is rotatably engaged with the housing via the at least two sliding bearings;

[0007] a dynamic sealing structure disposed in the housing, the dynamic sealing structure being spaced apart along the axial direction of the stator on a side of the sliding bearing close to the first end of the housing, and the dynamic sealing structure being disposed between an extended portion of the rotor and the housing;

[0008] An elastic tube is arranged outside the housing, the elastic tube is connected to the inner cavity of the housing, the inner cavity of the housing and the elastic tube are filled with insulating dielectric oil, and the gap between the sliding bearing and the rotor is connected to the inner cavity of the housing, and the insulating dielectric oil can form a pressure-bearing oil film at least at the contact interface between the sliding bearing and the rotor.

[0009] In one embodiment, the maximum deformation pressure value of the elastic tube is less than the maximum deformation pressure value of the shell, and the insulating dielectric oil can flow between the elastic tube and the shell under the drive of the internal and external pressure difference, so that the overall space formed by the elastic tube and the inner cavity of the shell always maintains a stable dynamic pressure equilibrium state with the external environment.

[0010] In one embodiment, the overall space formed by the elastic tube and the inner cavity of the shell is pressure balanced by the flow of insulating medium oil, and the pressure difference between the overall space formed by the elastic tube and the inner cavity of the shell and the external environment is satisfy: ,in, is the viscosity of the insulating medium oil, Q is the flow rate of the insulating medium oil, L is the flow path length of the insulating medium oil, A is the flow cross-sectional area of ​​the insulating medium oil, is the maximum elastic compensation pressure difference of the elastic tube, It is determined by the elastic modulus of the material of the elastic tube and the design deformation. The value range is 5×10^4 ~1×10^5Pa.

[0011] In one embodiment, the vacant space in the inner cavity of the housing is completely filled with the insulating dielectric oil, and the insulating dielectric oil can at least form a pressure-bearing oil film at the contact interface between the sliding bearing and the rotor.

[0012] In one embodiment, the sliding bearing includes a radial support portion and an axial support portion sequentially arranged along its axial direction, the outer diameter of the axial support portion is larger than the outer diameter of the radial support portion, and a step surface is formed between the radial support portion and the axial support portion.

[0013] In one embodiment, the outer diameter of the axial support portion is 15-20% larger than the outer diameter of the radial support portion.

[0014] In one embodiment, the pitch ratio of the stator winding is 5 / 6, and the winding slots on the stator core are skew slot structures.

[0015] In one embodiment, the gap between the stator and the rotor is an annular gap, and the gap width is D / 1000-D / 2000.

[0016] In one embodiment, one end of the elastic tube is sealed to the high-pressure connector, and the other end is sealed to the second end of the housing, and the second end is arranged opposite to the first end.

[0017] The high-voltage connector includes a power high-voltage connector and / or a signal high-voltage connector. The high-voltage connector is electrically connected to an electrical component installed in the housing via a cable, and the cable passes through the inner cavity of the elastic tube.

[0018] In one embodiment, the shell includes a shell body, a first end cover and a second end cover, the two ends of the shell body are sealed with the first end cover and the second end cover respectively, the elastic tube is connected to the first end cover, and the dynamic sealing structure is arranged in the second end cover.

[0019] In one embodiment, parts of the first end cover and the second end cover are axially embedded in the shell body, and an annular sealing ring is axially provided between parts of the first end cover and the second end cover and the inner wall of the shell body.

[0020] In one embodiment, a guide vane is further provided outside the first end portion of the shell.

[0021] In one embodiment, the dynamic sealing structure includes a stationary ring and a dynamic ring arranged between the rotor extension and the housing. The stationary ring and the dynamic ring are arranged in sequence along the axial direction. The roughness Ra of the contact surface between the stationary ring and the rotor extension is ≤0.1μm, and the flatness is ≤2μm. A wave spring sheet is also provided on the back of the dynamic ring facing the rotor extension. The elastic coefficient of the wave spring sheet satisfies that: when the external ambient pressure rises from 0MPa to 60MPa, the specific pressure of the sealing surface of the dynamic ring is maintained at 0.8-1.0MPa.

[0022] In one embodiment, the static ring is made of tungsten carbide-cobalt alloy, and the dynamic ring is made of polytetrafluoroethylene.

[0023] Another aspect of the present application provides an underwater propulsion device, which includes the low-vibration underwater propulsion motor.

[0024] Compared with the existing technology, the technical solution provided by this application has at least the following advantages:

[0025] 1) The embodiment of the present application provides a low-vibration underwater propulsion motor. By filling the motor with oil and connecting it to an external oil-filled elastic rubber tube, pressure compensation can be achieved to ensure that the internal and external pressures of the motor are in dynamic balance, thereby greatly improving the overall pressure-bearing capacity of the motor and enabling it to have a greater diving depth.

[0026] 2) A low-vibration underwater propulsion motor provided in an embodiment of the present application can significantly reduce the noise generated inside the motor by adopting radial and thrust integral oil-lubricated sliding bearings and using insulating dielectric oil filled in the housing to form a pressure-bearing oil film between the sliding bearings and the rotor and stator.

[0027] 3) The embodiment of the present application provides a low-vibration underwater propulsion motor, which can effectively reduce the vibration caused by electromagnetic excitation force by optimizing the pole-slot matching structure of the motor.

[0028] 4) The embodiment of the present application provides a low-vibration underwater propulsion motor. By adopting a multi-stage sealing structure formed by various sealing forms such as static seals and dynamic seals between the motor housing and the stator and rotor, and inside the stator, etc., the sealing performance of the motor as a whole can be effectively guaranteed, especially its working stability in deep-water annular diameter can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1 This is a structural schematic diagram of a low-vibration underwater propulsion motor in Example 1 of the present application;

[0031] Figure 2 This is a schematic structural diagram of a sliding bearing in Example 1 of the present application;

[0032] Figure 3a 、 Figure 3b Schematic diagram of oil film pressure distribution in Example 1 of the present application;

[0033] Figure 4 This is a schematic structural diagram of a stator in Example 1 of the present application;

[0034] Figure 5 This is a schematic diagram of a static sealing structure in Example 1 of the present application;

[0035] Figure 6 Schematic diagram of pressure distribution on both sides of a static sealing structure in Example 1 of the present application;

[0036] Figure 7 This is a schematic diagram of a dynamic sealing structure in Example 1 of the present application;

[0037] Figure 8 This is a structural diagram of a low-vibration underwater propulsion motor in Example 2 of the present application. DETAILED DESCRIPTION

[0038] The technical solution of the present application will be further described below in conjunction with specific embodiments. However, the implementation of the present application is not limited to these specific details, and may also be implemented in other ways different from those described herein. Therefore, the specific embodiments presented in the present application are only for illustration and not for limitation.

[0039] Example 1

[0040] See also Figure 1-Figure 7 The low-vibration underwater propulsion motor provided in this embodiment includes components such as a housing 110 , a stator 120 , a rotor 130 , and an elastic tube 200 .

[0041] The stator 120 and the rotor 130 are both sealed within the housing 110. The stator 120 is fixedly connected to the housing 110. The rotor 130 is rotatably mounted within the housing 110, and the stator 120 is sleeved on the rotor 130, with the two being coaxially arranged. There may be one or more elastic tubes 200, which are arranged outside the housing 110 and communicate with the inner cavity of the housing 110. The inner cavity of the housing 110 and the elastic tubes 200 are both filled with insulating medium oil. At the same time, the rotor 130 is connected to the housing 110 via two sliding bearings 140 spaced apart along its axial direction, and the extended portion of the rotor 130 is also engaged with the housing 110 via a dynamic sealing structure 180. The interior of the sliding bearing 140 and the gap between the stator 120 and the rotor 130 are both connected to the inner cavity of the housing 110. The maximum deformation pressure value of the elastic tube 200 is lower than the maximum deformation pressure value of the housing 110. Driven by the internal and external pressure difference, the insulating dielectric oil can flow between the elastic tube 200 and the housing 110, so that the overall space formed by the elastic tube 200 and the inner cavity of the housing 110 always maintains a stable dynamic pressure equilibrium with the external environment. In this embodiment, the inner cavity pressure of the housing 110 can be maintained at 0.1 MPa-0.2 MPa.

[0042] It should be noted that the two sliding bearings 140 are respectively arranged to cooperate with the two end portions of the rotor 130 , and the dynamic sealing structure 180 is arranged at intervals along the axial direction of the stator 120 on one side of the sliding bearing 140 close to the first end of the housing 110 .

[0043] Furthermore, the empty space in the inner cavity of the housing 110 is completely filled with the insulating dielectric oil, and the insulating dielectric oil can at least form a pressure-bearing oil film at the contact interface between the sliding bearing 140 and the rotor 130 .

[0044] Specifically, the inner cavity of the propulsion motor housing 110 is filled with oil by a hose, and a certain pressure is maintained inside the hose. As the propulsion motor dives, the hose and its propulsion motor are simultaneously subjected to the same pressure as the external seawater. At this time, the hose is squeezed and deformed, causing the internal pressure of the propulsion motor to increase, but the hose and its propulsion motor maintain a stable dynamic pressure balance with the external seawater, so the propulsion motor maintains a certain pressure difference with the external seawater. Typically, the pressure of the insulating dielectric oil injected in the initial state is around 0.1 MPa, but the propeller will eventually dive to a pressure environment of tens of MPa. The effect of the initially injected insulating dielectric oil prevents seawater from entering the propeller through the dynamic sealing structure 180, ensuring the stability of the propeller. If the initial pressure in the inner cavity of the housing 110 is 0.1 MPa, then the pressure difference between the propeller and the outside will remain stable at 0.1 MPa during the dive.

[0045] Specifically, the elastic tube 200 and the inner cavity of the shell 110 form a whole space to achieve pressure balance through the flow of insulating medium oil, and the pressure difference between the whole space formed by the elastic tube 200 and the inner cavity of the shell 110 and the external environment is satisfy: ,in, is the viscosity of the insulating medium oil, Q is the flow rate of the insulating medium oil, L is the flow path length of the insulating medium oil, A is the flow cross-sectional area of ​​the insulating medium oil, is the maximum elastic compensation pressure difference of the elastic tube 200, It is determined by the elastic modulus of the material of the elastic tube 200 and the designed deformation amount. The value range is 5×10^4~1×10^5Pa.

[0046] For further information, see Figure 3a 、 Figure 3b The gap between the stator 120 and the rotor 130 is an annular gap. In order to optimize the influence of the oil film of the sliding bearing 140 on the dynamics of the rotor 130, this gap is designed to be between D / 1000 and D / 2000. At this time, the dynamic stiffness and dynamic damping of the oil film can effectively reduce the vibration of the rotor 130.

[0047] Furthermore, the insulating medium oil may be insulating oil, white mineral oil, transformer oil, etc., but is not limited thereto.

[0048] This propulsion motor uses internal oil filling to balance external pressure, which can produce multiple benefits. For example, the propulsion motor's interior is filled with oil through a soft elastic tube 200 (also called a hose), ensuring a constant internal pressure. As the propulsion motor descends, the elastic tube 200 is squeezed and deformed, causing the internal pressure of the propulsion motor to increase, while maintaining a certain pressure differential with the external seawater. This method allows the propeller to dive to deeper waters. Second, the propulsion motor's interior is completely isolated from the external seawater, preventing it from corroding. Third, the insulating oil in the propulsion motor forms an effective oil film between the stator 120 and the rotor 130, ensuring the rotor 130's free rotation. As the rotor 130's rotational speed increases, the oil film develops a certain degree of stiffness and damping, effectively reducing vibration of the rotor 130. At the same time, as the propulsion motor's underwater depth changes, the insulating oil can flow between the elastic tube 200 and the motor's inner cavity, allowing the insulating oil that makes up the aforementioned oil film to be replaced. This prevents the oil film from being degraded or even lost in lubrication after long-term operation due to the incorporation of solid particles detached from the rotor 130 and bearing surfaces. Fourthly, the insulating oil filling the motor's interior shortens the heat conduction path within the motor, accelerating heat transfer from the motor to the outside, and helping to reduce thermal-mechanical coupling effects. In particular, when the propulsion motor moves from deep water to shallow water, some of the insulating oil can flow from the motor into the elastic tube 200, carrying some heat with it, accelerating heat dissipation from the motor and reducing its infrared signature.

[0049] Please also refer to Figure 2In this embodiment, the sliding bearing 140 includes a radial bearing portion and an axial bearing portion arranged in sequence along the self axial direction, the outer diameter of the axial bearing portion is larger than the outer diameter of the radial bearing portion, and a stepped surface is formed between the radial bearing portion and the axial bearing portion. More specifically, the outer diameter of the axial bearing portion is 15-20% larger than the outer diameter of the radial bearing portion. Specifically, the radial bearing portion and the axial bearing portion are both cylindrical structures, and the sliding bearing 140 as a whole presents an L-shaped integrated cylindrical structure. The radial bearing portion serves as the main functional part of the sliding bearing 140, and mainly bears the radial force. The axial bearing portion mainly bears the axial thrust. It can be understood that the contact interface between the sliding bearing 140 and the rotor 130 is a stepped surface. Based on such a structural design, the sliding bearing 140 can simultaneously bear the radial force and the axial force, and as the rotating speed of the rotor 130 increases, the pressure oil film is formed between the radial bearing portion, the axial bearing portion and the rotor 130, thereby offsetting the radial force and the circumferential thrust of the propulsion motor. Based on such a structural design, not only the overall structural stability can be improved, but also the vibration between the sliding bearing 140 and the rotating shaft 170, the rotor 130 and other components can be reduced. For example, the sliding bearing 140 can be a high-molecular low-vibration oil lubricated bearing.

[0050] Specifically, the gap between the sliding bearing 140 and the rotor 130 is an annular gap. In order to optimize the influence of the oil film of the sliding bearing 140 on the dynamics of the rotor 130, the gap width is D / 1000-D / 2000, and D is the inner diameter of the sliding bearing 140. At this time, the dynamic stiffness and dynamic damping of the oil film can effectively reduce the vibration of the rotor 130.

[0051] In this embodiment, the pole-slot matching structure of the propulsion motor is also optimally designed to reduce the vibration caused by the electromagnetic excitation force. Specifically, the main structure of the stator 120 is the same as the conventional structure known in the art. In order to improve the performance of the motor and reduce the noise of the motor as much as possible, the present application discards the fractional slot winding scheme of the multi-stage few-slot concentrated winding, and adopts distributed winding. In order to weaken the harmonic magnetic motive force, a short-pitch winding is usually used. In order to weaken the 5th harmonic and the 7th harmonic, the pitch ratio of the stator 120 in the present application is 5 / 6, and the spatial layout is generally three-phase symmetrical. The magnetic flux density harmonic content analysis shows that, for example, the stator 120 in the present application adopts a 36-slot 6-pole scheme, fractional slot winding, q (number of slots per phase per pole) = 2, the electromagnetic force wave frequency only contains even frequency, the rotor 130 magnetic flux density order is 1, 3, 5, 7…, the stator 120 is 1, -5, 7…, the pole-slot matching of the stator 120 is integer slot, and the stator 120 has less magnetic flux density harmonic content and does not contain even components. More specifically, the winding slot on the core of the stator 120 is a skew slot structure.

[0052] Please refer again to Figure 1The shell 110 in this embodiment includes a shell body 110, a first end cover 150 and a second end cover 160. The two ends of the shell body 110 are sealed with the first end cover 150 and the second end cover 160 respectively. The elastic tube 200 is connected to the first end cover 150, and the dynamic sealing structure 180 is arranged in the second end cover 160.

[0053] Furthermore, parts of the first end cover 150 and the second end cover 160 are axially embedded in the shell body 110 , and an annular sealing ring is axially provided between parts of the first end cover 150 and the second end cover 160 and the inner wall of the shell body 110 .

[0054] See also Figure 5 and Figure 6 The propulsion motor's sealing system utilizes O-rings 190 to seal the mating areas of the motor's stationary components. The compression and extension of the O-rings 190 are calculated to achieve optimal sealing. The stator 120 and flange are spaced apart, with two O-rings 190 positioned between them to create a two-stage seal. This gradually reduces seawater pressure, allowing the second-stage O-ring 190 to mitigate the applied pressure and effectively enhance the stator 120's sealing performance.

[0055] See also Figure 7The sealing of the rotating parts adopts a stable mechanical dynamic seal to ensure the overall sealing of the propulsion motor. A mechanical dynamic seal is used for rotational sealing between the propulsion motor stator 120 and the rotor 130. Specifically, the dynamic sealing structure 180 between the propulsion motor stator 120 and the rotor 130 includes a static ring 181 and a dynamic ring 182 arranged between the extended portion of the rotor 130 and the housing 110. The static ring 181 and the dynamic ring 182 are arranged in sequence along the axial direction. The roughness Ra of the contact surface between the static ring 181 and the extended portion of the rotor 130 is ≤ 0.1 μm, and the flatness is ≤ 2 μm. A wave spring sheet is also provided on the back of the dynamic ring 182 facing the extended portion of the rotor 130. The elastic coefficient of the wave spring sheet satisfies: when the external ambient pressure rises from 0 MPa to 60 MPa, the specific pressure of the sealing surface of the dynamic ring 182 is maintained at 0.8-1.0 MPa. Exemplarily, the material of the static ring 181 is tungsten carbide-cobalt alloy material, and the material of the dynamic ring 182 is polytetrafluoroethylene material. Specifically, the mechanical dynamic seal transfers the sealing part to the surfaces of the well-controlled static ring 181 and the dynamic ring 182. The dynamic ring 182 is pushed by the spring and generates a pressure greater than the external environment with the static ring. At this time, a sealing effect can be generated to obtain a rotating seal for the propulsion motor and improve the sealing effect. In addition, through such a design, a prestress is maintained between the mechanical dynamic seal structure 180 and the rotor 130, which can ensure the stability of the rotor 130 and thus reduce vibration. In addition, maintaining the specific pressure at 0.8-1Mpa can minimize the heat generated by the friction of the sealing surface.

[0056] In this embodiment, an interference fit is employed between the stator 120 core and the housing 110. Furthermore, the interior of the stator 120 is infused with a high-strength composite epoxy resin. This process further enhances the integrity of the stator 120 and, more importantly, its rigidity, allowing it to withstand greater pressure.

[0057] In this embodiment, stator 120 is constructed from high-quality silicon steel sheets, and the stator 120 windings are specially shaped. Stator 120 is internally infused with a high-strength composite epoxy resin. Compared to conventional motor glue potting, stator 120 exhibits high rigidity, excellent thermal conductivity, insulation, and aging resistance. In this embodiment, the contact surfaces between internal components of stator 120 are designed with high-pressure sealing rings to prevent seawater penetration. In this embodiment, all components of stator 120 are constructed from aluminum alloy, and the high-pressure sealing rings are constructed from fluororubber. These lightweight, corrosion-resistant materials ensure the propeller can operate longer in seawater.

[0058] In this embodiment, the rotor 130 is protected by a carbon fiber sheath to ensure that the rotor 130 magnets are completely fixed and fully protected against high-speed centrifugal forces. The contact surfaces of all stationary parts are designed with high-pressure resistant sealing rings, and the rotor 130 core is epoxy-encapsulated with glue, so the rotor 130 has excellent sealing performance as a whole.

[0059] In this embodiment, the propulsion motor's outer surface components are made of aluminum alloy, which not only contributes to the motor's lightweight design but also mitigates or prevents corrosion from prolonged seawater contact. Preferably, the propulsion motor's outer surface is hard-oxidized to further mitigate seawater corrosion. Preferably, some motor components, such as the shaft cap, can be made of sacrificial anode material. This, in conjunction with components such as the rotating shaft 170, forms a galvanic cell, mitigating or preventing seawater corrosion on the housing 110 and flange components.

[0060] In this embodiment, except for the stator 120 core, windings, etc., other components such as sensors can be encapsulated by epoxy resin to ensure reliability.

[0061] In this embodiment, the elastic tube 200 can be an elastic rubber tube, one end of which is sealedly connected to a high-voltage connector and the other end is sealedly connected to the housing 110. The high-voltage connectors may include a power high-voltage connector 310 and a signal high-voltage connector 320. The high-voltage connectors are electrically connected to electrical components installed in the housing 110 via cables, which pass through the inner cavity of the elastic tube 200. Therefore, the elastic tube 200 not only provides pressure compensation but also provides protection for communication cables, power cables, etc.

[0062] Example 2

[0063] See also Figure 8 The structure of a low-vibration underwater propulsion motor provided in this embodiment is basically the same as that of Example 1, with the difference being that a streamlined guide vane 400 is added to the first end of the shell 110, which can reduce the flow resistance and eddy current of the propulsion motor itself and increase the overall efficiency of the propulsion motor.

[0064] The above embodiments are intended only to illustrate the technical concepts and effects of this application, with the goal of enabling those familiar with this technical field to understand the content of this application and implement it accordingly. However, these embodiments do not constitute a limitation on the scope of protection of this application. Any equivalent transformations or modifications made based on the spirit and technical ideas of this application should be covered by the claims of this application.

Claims

1. A low-vibration underwater propulsion motor, comprising a stator and a rotor sealed in a housing, wherein the stator is fixedly connected to the housing, the rotor is rotatably mounted in the housing, and the stator is sleeved on the rotor; It is characterized in that Also includes: At least two sliding bearings are fixedly disposed in the housing, and at least two sliding bearings are spaced apart at both ends of the stator along the axial direction of the stator. The rotor is rotatably engaged with the housing via the at least two sliding bearings, and a gap width between the sliding bearings and the rotor is D / 1000-D / 2000, where D is the inner diameter of the sliding bearing; a dynamic sealing structure disposed in the housing, the dynamic sealing structure being spaced apart along the axial direction of the stator on a side of the sliding bearing close to the first end of the housing, and the dynamic sealing structure being disposed between an extended portion of the rotor and the housing; An elastic tube is arranged outside the shell, the elastic tube is communicated with the inner cavity of the shell, the inner cavity of the shell and the elastic tube are filled with insulating medium oil, and the gap between the sliding bearing and the rotor is communicated with the inner cavity of the shell.

2. The low-vibration underwater propulsion motor according to claim 1, characterized in that: The maximum deformation pressure value of the elastic tube is smaller than the maximum deformation pressure value of the shell. The insulating dielectric oil can flow between the elastic tube and the shell under the drive of the internal and external pressure difference, so that the overall space formed by the elastic tube and the inner cavity of the shell always maintains a stable dynamic pressure equilibrium state with the external environment.

3. The low-vibration underwater propulsion motor according to claim 2, characterized in that: The elastic tube and the shell cavity form a whole space to achieve pressure balance through the flow of insulating medium oil, and the pressure difference between the elastic tube and the shell cavity and the external environment is satisfy: ,in, is the viscosity of the insulating medium oil, Q is the flow rate of the insulating medium oil, L is the flow path length of the insulating medium oil, A is the flow cross-sectional area of ​​the insulating medium oil, is the maximum elastic compensation pressure difference of the elastic tube, It is determined by the elastic modulus of the material of the elastic tube and the design deformation. The value range is 5×10^4 ~1×10^5Pa.

4. The low-vibration underwater propulsion motor according to claim 1, characterized in that: The vacant space in the inner cavity of the housing is completely filled with the insulating dielectric oil, and the insulating dielectric oil can at least form a pressure-bearing oil film at the contact interface between the sliding bearing and the rotor.

5. The low-vibration underwater propulsion motor according to claim 1, characterized in that: The pitch ratio of the stator winding is 5 / 6, and the winding slots on the stator core are skew slot structures.

6. The low-vibration underwater propulsion motor according to claim 1, characterized in that: The sliding bearing includes a radial support portion and an axial support portion sequentially arranged along its axial direction. The outer diameter of the axial support portion is larger than the outer diameter of the radial support portion. A step surface is formed between the radial support portion and the axial support portion.

7. The low-vibration underwater propulsion motor according to claim 6, characterized in that: The outer diameter of the axial support portion is 15-20% larger than the outer diameter of the radial support portion.

8. The low-vibration underwater propulsion motor according to claim 1, characterized in that: One end of the elastic tube is sealed with the high-pressure connector, and the other end is sealed with the second end of the shell, and the second end is arranged opposite to the first end.

9. The low-vibration underwater propulsion motor according to claim 8, characterized in that: The high-voltage connector includes a power high-voltage connector and / or a signal high-voltage connector. The high-voltage connector is electrically connected to the electrical components installed in the housing through a cable, and the cable passes through the inner cavity of the elastic tube.

10. The low-vibration underwater propulsion motor according to claim 1, characterized in that: The shell includes a shell body, a first end cover and a second end cover. The two ends of the shell body are sealed with the first end cover and the second end cover respectively. The elastic tube is connected to the first end cover, and the dynamic sealing structure is arranged in the second end cover.

11. The low-vibration underwater propulsion motor according to claim 10, characterized in that: Parts of the first end cover and the second end cover are axially embedded in the shell body, and an annular sealing ring is axially provided between parts of the first end cover and the second end cover and the inner wall of the shell body.

12. The low-vibration underwater propulsion motor according to claim 1, characterized in that: A guide vane is further provided outside the first end portion of the shell.

13. The low-vibration underwater propulsion motor according to claim 1, characterized in that: The dynamic sealing structure includes a stationary ring and a dynamic ring arranged between the rotor extension part and the housing. The stationary ring and the dynamic ring are arranged in sequence along the axial direction. The roughness Ra of the contact surface between the stationary ring and the rotor extension part is ≤0.1μm, and the flatness is ≤2μm. A wave spring sheet is also provided on the back of the dynamic ring facing the rotor extension part. The elastic coefficient of the wave spring sheet satisfies that: when the external environmental pressure rises from 0MPa to 60MPa, the specific pressure of the sealing surface of the dynamic ring is maintained at 0.8-1.0MPa.

14. The low-vibration underwater propulsion motor according to claim 13, characterized in that: The material of the static ring is tungsten carbide-cobalt alloy material, and the material of the dynamic ring is polytetrafluoroethylene material.

15. An underwater propeller, characterized in that: include: The low-vibration underwater propulsion motor according to any one of claims 1 to 14.

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