Low-vibration low-noise underwater propulsion motor

Abstract

The application discloses a low-vibration and low-noise underwater propulsion motor, which comprises a shell, a stator, a rotor, a rotating shaft and a pressure compensation mechanism, wherein the pressure compensation mechanism comprises a compensator body and an elastic element; the compensator body is in sealing connection with one end of the shell, and a sealed containing space is arranged in the compensator body; the elastic element is arranged in the sealed containing space and connected with or contacted with a thrust sliding bearing; the thrust sliding bearing is movably arranged on the rotating shaft; the inner cavity of the shell is filled with insulating oil with a set pressure; and the pressure compensation mechanism can make the insulating oil in the propulsion motor have a pressure greater than that of the external environment. The low-vibration underwater propulsion motor has the advantages of low vibration and low noise, can adapt to different diving depths and keep good sealing effect, 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 and low-noise underwater propulsion motor. Background Art

[0002] As the core power component of deep-sea equipment, the performance of underwater propulsion motors directly determines the maneuverability, stealthiness, and operating depth of underwater vehicles. To cope with the high-pressure environment of the deep sea, traditional underwater propulsion motors usually use internal insulating oil filling to achieve pressure balance and improve the pressure resistance of the motor windings. However, with the dynamic changes in diving depth, the pressure difference between the inside of the motor and the external environment fluctuates significantly, resulting in a sharp decline in the reliability of the sealing structure. In particular, dynamic sealing parts are prone to micro-gaps due to material fatigue or deformation, causing insulating oil leakage, which in turn causes problems such as deterioration of the internal insulation performance of the motor and reduced heat dissipation efficiency. In severe cases, it may even cause winding short circuits or permanent magnet demagnetization, threatening the safe operation of the vehicle.

[0003] Existing technologies typically address sealing issues by employing multi-layer composite sealing structures or high-precision machining processes to improve the adaptability of the sealing interface. However, these solutions significantly increase manufacturing costs and, under long-term alternating pressure loads, can still cause the sealing materials to age and fail. Therefore, there is an urgent need for a pressure-resistant and sealing technology solution for underwater propulsion motors that can adapt to a wide range of diving depths and offer high sealing reliability. Summary of the Invention

[0004] The main purpose of this application is to provide a low-vibration and low-noise underwater propulsion motor to overcome the defects of the prior art.

[0005] In order to achieve the above-mentioned purpose of the invention, this application provides the following technical solutions.

[0006] One aspect of the present application provides a low-vibration and low-noise underwater propulsion motor, comprising: a housing, and a stator, a rotor, two radial sliding bearings, and a thrust sliding bearing installed in an inner cavity of the housing, wherein the stator is sleeved on the rotor, the rotor is connected to a rotating shaft, the rotating shaft is rotatably engaged with the housing via the radial sliding bearing and the thrust sliding bearing, respectively, the rotating shaft is sealed with a first end of the housing via a mechanical dynamic seal structure, the rotating shaft is also fixedly connected to a propeller disposed outside the housing, and the inner cavity of the housing is further filled with insulating oil having a set pressure, wherein the set pressure is greater than the ambient pressure outside the housing;

[0007] In addition, the propulsion motor also includes a pressure compensation mechanism, which is axially arranged at the second end of the shell. The pressure compensation mechanism includes a compensator body and an elastic element. The compensator body is sealed with the shell. A sealed accommodating space is provided in the compensator body. The side of the compensator body facing the inner cavity is an elastic diaphragm. The elastic diaphragm is in direct contact with the insulating oil in the inner cavity. The elastic element is arranged in the sealed accommodating space and is connected or in contact with the elastic diaphragm. The elastic element is in an elastic compression state. The elastic diaphragm can be deformed axially under the action of external force, wherein the external force includes the elastic force of the elastic element and the pressure of the insulating oil.

[0008] Furthermore, the axis of the elastic element is parallel to the axis of the rotating shaft, and the aspect ratio of the elastic element is , the pressure compensation mechanism satisfies:

[0009] ;

[0010] Where m is the mass of the elastic element, c is the damping of the elastic element, t is the duration of deformation of the elastic element, A is the effective pressure-bearing area of ​​the pressure compensation mechanism, P is the pressure of the insulating oil in the inner cavity of the shell, k is the stiffness of the elastic element, and x is the deformation of the elastic element.

[0011] Furthermore, the pressure compensation mechanism also includes a diaphragm pressure cover, which is axially arranged between the elastic element and the elastic diaphragm, and is connected or in contact with the elastic element and the elastic diaphragm respectively. The elastic element applies its elastic force to the elastic rubber diaphragm through the diaphragm pressure cover, and the effective pressure-bearing area of ​​the pressure compensation mechanism is the contact area between the diaphragm pressure cover and the elastic diaphragm.

[0012] Furthermore, the elastic element includes a spring.

[0013] Furthermore, the two radial sliding bearings and the thrust sliding bearing are arranged at intervals along the axial direction, and the thrust sliding bearing is located on the side of the radial sliding bearing close to the pressure compensation mechanism. One end of the rotating shaft passes through a radial sliding bearing and is inserted into the thrust sliding bearing, and cooperates with the thrust sliding bearing to form a clamping structure.

[0014] Furthermore, the thrust sliding bearing is a tilting pad bearing.

[0015] Furthermore, a thrust plate is fixedly provided on the rotating shaft, and the thrust plate is in contact with or connected to the thrust sliding bearing.

[0016] Furthermore, the gap between the stator and the rotor is connected to the inner cavity of the housing, the insulating oil fills the inner cavity of the housing, and part of the insulating oil is filled between the rotating shaft and the radial sliding bearing, between the rotating shaft and the thrust sliding bearing, and in the gap of the radial sliding bearing, and forms a pressure-bearing oil film.

[0017] Furthermore, the pressure-bearing oil film between the radial sliding bearing and the rotating shaft is a wedge-shaped oil film structure. When the rotor rotates, the pressure in the wedge-shaped oil film structure increases as the rotor's rotational speed increases. It should be noted that the pressure in the wedge-shaped oil film structure does not increase indefinitely, but only reaches force equilibrium with the rotor and other related structures, at which point it ceases to increase.

[0018] Furthermore, the gap between the radial sliding bearing and the rotating shaft is an annular gap. To ensure a low-vibration motion mechanism, the width of the radial sliding bearing gap is D / 1000 to 2D / 1000, where D is the outer diameter of the radial sliding bearing.

[0019] Furthermore, two bearing supports are fixedly provided in the housing, each of the bearing supports is correspondingly provided on the periphery of a radial sliding bearing, and the bearing supports are movably matched with the radial sliding bearing and are used to limit the axial movement of the radial sliding bearing.

[0020] Furthermore, the two radial sliding bearings are defined as a first radial sliding bearing and a second radial sliding bearing, the first radial sliding bearing is axially located between the pressure compensation mechanism and the second radial sliding bearing, the first radial sliding bearing is a straight cylindrical structure, and the second radial sliding bearing is an L-shaped cylindrical structure.

[0021] Furthermore, the first end of the shell is sealed with an end cover, and the mechanical dynamic sealing structure is arranged in the end cover.

[0022] Furthermore, a resolver encoder is installed in the end cover for monitoring the working status of the motor, and the resolver encoder and the rotor have the same number of pole pairs.

[0023] In one embodiment, the rotating shaft includes a first shaft segment and a second shaft segment fixedly connected along the axial direction, the first shaft segment is composed of a magnetic metal material and serves as a rotor core, the second shaft segment is composed of a corrosion-resistant material, the first shaft segment is entirely arranged in the shell, and the second shaft segment is partially arranged outside the shell.

[0024] In one embodiment, the compensator body is entirely embedded in the shell, and the tail of the compensator body is connected to the second end of the shell in a surrounding and sealed manner.

[0025] Another aspect of the present application provides an underwater propulsion device, which includes the low-vibration and low-noise underwater propulsion motor.

[0026] Compared with the existing technology, the technical solution provided by this application has at least the following advantages:

[0027] First, by setting a pressure compensation mechanism in the propulsion motor and injecting insulating oil with a certain pressure into the propulsion motor, the elastic element in the pressure compensation mechanism is forced to maintain a certain deformation, so that the propulsion motor can maintain a certain pressure and maintain a certain pressure difference between the inside and the outside. In particular, the internal and external pressure difference generated by the pressure compensation mechanism on the propulsion motor is smaller than the specific pressure generated by the mechanical dynamic sealing structure. When the propulsion motor is running underwater, the pressure compensation mechanism can maintain the pressure difference between the inside and the outside of the propulsion motor, thereby effectively ensuring the sealing of the propulsion motor at different diving depths and reducing or eliminating the leakage of insulating oil.

[0028] Secondly, by adopting various forms of bearings, for example, a low-vibration L-shaped oil-lubricated bearing is set at one end of the rotating shaft as the power output end, and an independent radial sliding bearing and an axial thrust sliding bearing with a large contact area are set at the other end, the effect of the axial thrust can be increased, and the insulating oil filled in the housing is used to form a pressure oil film between the rotating shaft and the bearing and between the rotor and the stator, which can significantly reduce the noise generated inside the motor.

[0029] Third, 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, as well as inside the stator, the overall sealing performance of the motor can be effectively guaranteed, especially its working stability in deep water annular diameter can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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.

[0031] Figure 1 This is a schematic structural diagram of a low-vibration and low-noise underwater propulsion motor according to an embodiment of the present application;

[0032] Figure 2 This is an axial cross-sectional view of a low-vibration and low-noise underwater propulsion motor according to an embodiment of the present application;

[0033] Figure 3 This is a schematic structural diagram of a radial sliding bearing in an embodiment of the present application;

[0034] Figure 4 This is a schematic structural diagram of another radial sliding bearing in an embodiment of the present application;

[0035] Figure 5 This is a schematic structural diagram of a thrust sliding bearing in an embodiment of the present application;

[0036] Figure 6 This is a schematic diagram of the oil film structure between a radial sliding bearing / thrust sliding bearing and a rotating shaft in an embodiment of the present application. DETAILED DESCRIPTION

[0037] 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.

[0038] See also Figure 1-Figure 5 A low-vibration underwater propulsion motor includes components such as a shell 100, a stator 200, a rotor 300, and a rotating shaft 400. The stator 200 and the rotor 300 are both encapsulated in the inner cavity of the shell 100, the main part of the rotating shaft 400 is encapsulated in the inner cavity of the shell 100, a part of the rotating shaft 400 extends from the inner cavity of the shell 100 and is fixedly connected to the propeller, the stator 200 is sleeved on the rotor 300, the rotor 300 rotates with the stator 200, the stator 200 is fixedly connected to the shell 100, the rotor 300 is sleeved on the rotating shaft 400 and connected to the rotating shaft 400, and the rotor 300 and the rotating shaft 400 both rotate with the shell 100.

[0039] Specifically, the rotating shaft 400 is matched with the housing 100 through two radial sliding bearings and a thrust sliding bearing 600 arranged at intervals along the axial direction. The two radial sliding bearings (i.e., the first radial sliding bearing 510 and the second radial sliding bearing 520 hereinafter, the same below) and the thrust sliding bearing 600 are fixedly matched with the housing 100. One end of the rotating shaft 400 passes through the two radial sliding bearings in sequence and is inserted into the thrust sliding bearing 600, and cooperates with the thrust sliding bearing 600 to form a clamping structure. Among them, the two radial sliding bearings are mainly used to limit the radial freedom of the rotating shaft 400 and the rotor 300, to ensure that the rotating shaft 400 does not produce radial displacement, and to keep the rotating shaft 400, the rotor 300 and the stator 200 coaxially arranged. The radial sliding bearings and the thrust sliding bearing 600 cooperate and are used to limit the axial displacement of the rotating shaft 400. The thrust sliding bearing 600 can also withstand the huge thrust generated by the propeller. It can be understood that the two radial sliding bearings and the thrust sliding bearing 600 are coaxially arranged, and the rotating shaft 400 and the radial sliding bearing can only produce relative movement in the axial direction.

[0040] Specifically, there is a clearance fit between the stator 200 and the rotor 300, and between the radial sliding bearing, the thrust sliding bearing 600 and the rotating shaft 400. The gap between the stator 200 and the rotor 300, and the gap between the radial sliding bearing, the thrust sliding bearing 600 and the rotating shaft 400 are connected to the inner cavity of the housing 100. In addition, the inner cavity of the housing 100 is filled with insulating oil with a set pressure. The insulating oil is also filled in the gap between the stator 200 and the rotor 300, the gap between the radial sliding bearing and the rotating shaft 400, and the gap between the thrust sliding bearing 600 and the rotating shaft 400, and forms a pressure-bearing oil film, as shown in FIG. Figure 6 As shown, the pressure-bearing oil film enables the rotor 300 to form a low-vibration rotor motion mechanism. Specifically, the vacant space within the housing 100 cavity is completely filled with insulating oil, and the pressure within the housing 100 cavity is maintained above a set value. The set value can be determined based on the maximum submersible depth of the motor, and the two are positively correlated. For example, in this embodiment, the set value can be set to 0.2-1 MPa. Exemplary insulating oils include, but are not limited to, insulating oil, white mineral oil, or transformer oil.

[0041] Specifically, the pressure-bearing oil film between the radial sliding bearing and the rotating shaft 400 is a wedge-shaped oil film structure. When the rotor 300 rotates, the pressure in the wedge-shaped oil film structure increases as the speed of the rotor 300 increases. Specifically, the gap between the radial sliding bearing and the rotating shaft 400 is an annular gap (the gap between the inner ring of the radial sliding bearing and the surface of the rotating shaft). To ensure a low-vibration motion mechanism, the width of the radial sliding bearing gap is D / 1000 to 2D / 1000, where D is the outer diameter of the radial sliding bearing.

[0042] Specifically, the stator 200 is fixed to the housing 100 through a structure / method known in the art. In the radial direction, there is a gap between the stator 200 and the rotor 300. The rotor 300 and the rotating shaft 400 also have the freedom to move in the axial direction. The structure of the stator 200 and the rotor 300 can adopt a structure known in the art. The configuration structure between the stator 200 and the rotor 300 is also known in the art and is not specifically limited here. In this embodiment, except for the stator 200 core, windings, etc., the remaining components such as sensors can be encapsulated with epoxy resin to ensure reliability.

[0043] In this embodiment, the stator 200 can be made of high-quality silicon steel sheets, and the stator 200 windings are specially shaped. The interior of the stator 200 is poured with a high-strength composite epoxy resin. Compared with ordinary motor glue, it has the characteristics of high rigidity, thermal conductivity, good insulation, and excellent aging resistance. In this embodiment, the contact surfaces of the internal parts of the stator 200 are designed with high-pressure sealing rings to prevent the penetration of seawater. In this embodiment, the various components included in the stator 200 can be made of aluminum alloy materials, and the high-pressure sealing rings are made of fluororubber materials. These are all lightweight and corrosion-resistant materials that can ensure that the propeller can operate longer in seawater.

[0044] In this embodiment, the rotor 300 is sheathed with carbon fiber material to ensure that the rotor 300 magnets are completely fixed and can be fully protected under the action of high-speed centrifugal force. The contact surfaces of all stationary parts are designed with high-pressure resistant sealing rings, and the rotor 300 core is epoxy-encapsulated with glue, so the overall sealing performance is excellent.

[0045] In this embodiment, the outer surface components of the propulsion motor are made of aluminum alloy, which not only contributes to the motor's lightweight design but also mitigates or prevents corrosion from prolonged contact with seawater. Preferably, the outer surface of the propulsion motor is hard-oxidized to further mitigate corrosion from seawater. Preferably, certain motor components, such as the shaft cap, can be made of sacrificial anode material. This, in conjunction with the housing 100 and flange, forms a galvanic cell, mitigating or preventing corrosion of the housing 100 and flange components from seawater.

[0046] Specifically, the rotating shaft 400 is divided into two parts, specifically comprising a first shaft segment and a second shaft segment fixedly connected along the axial direction. The first shaft segment is entirely located within the inner cavity of the housing 100 and connected to the rotor 300. The second shaft segment, located adjacent to the first shaft segment, is disposed within the inner cavity of the housing 100, while a portion facing away from the first shaft segment is disposed outside the housing 100 and fixedly connected to the propeller. More specifically, the first shaft segment is composed of a magnetically conductive metal material (e.g., magnetically conductive carbon steel) and serves as the core of the rotor 300, enhancing the motor's magnetic circuit. The second shaft segment is composed of a corrosion-resistant material (e.g., stainless steel or a corrosion-resistant titanium alloy) to adapt to the operating environment. Specifically, because the rotating shaft 400 is composed of two parts with a large span and long stroke, the two shaft segments need to be machined separately. A wear-resistant coating, such as tungsten carbide, is then applied to each segment through spraying or other methods. Finally, the segments are assembled together and subjected to integral grinding or other processing.

[0047] More specifically, the two radial sliding bearings are defined as a first radial sliding bearing 510 and a second radial sliding bearing 520. The thrust sliding bearing 600, the first radial sliding bearing 510, and the second radial sliding bearing 520 are sequentially arranged along the axial direction. Specifically, the first radial sliding bearing 510 and the thrust sliding bearing 600 cooperate with the first shaft segment, and the second radial sliding bearing 520 cooperates with the second shaft segment. Specifically, two bearing supports are further disposed within the housing 100. The bearing supports are fixedly engaged with the housing 100, each of which is disposed on the periphery of a corresponding radial sliding bearing (typically, the bearing supports can be sleeved on the radial sliding bearing). The bearing supports cooperate with the radial sliding bearings (possibly through a detachable structure known in the art) and are used to limit the axial movement of the radial sliding bearings. Typically, the first radial sliding bearing 510 can be a straight cylindrical structure. The inner annular surface of the bearing support member that cooperates with the first radial sliding bearing 510 is provided with a groove-like structure that matches the first radial sliding bearing 510. The first radial sliding bearing 510 is partially embedded in the groove-like structure, thereby maintaining the position of the first radial sliding bearing 510. The second radial sliding bearing 520 can have the same or different structure as the first radial sliding bearing 510. Typically, the second radial sliding bearing 520 can be an L-shaped cylindrical structure, that is, one end of the second radial sliding bearing 520 has an annular protrusion extending radially outward. Part of the second radial sliding bearing 520 can nest with or abut against the rotating shaft 400, the housing 100, and the bearing support member to form a stop structure, thereby maintaining the position and posture of the second radial sliding bearing 520 within the housing 100. In this embodiment, the sliding bearings of the propulsion motor are of two types. The protruding end is a low-vibration L-shaped oil-lubricated bearing (i.e., the second radial sliding bearing 520), and the rear end is an independent radial sliding bearing (i.e., the first radial sliding bearing 510) and a thrust sliding bearing 600 with a large contact area, which can increase the effect of axial thrust.

[0048] In this embodiment, please refer to Figure 3 The thrust sliding bearing 600 is a tilting pad bearing. The pads of the tilting pad bearing can be divided into several petals within the circumference, and each pad can swing at its own fulcrum, making it easier to form an oil wedge, which can improve the stiffness and damping of the oil film, thereby improving the support capacity of the thrust sliding bearing 600 and effectively reducing the vibration noise of the motor. Figure 4 and Figure 5 , radial sliding bearings can adopt cylindrical dynamic pressure lubricated bearings or split dynamic pressure lubricated bearings, etc.

[0049] For details, please refer to Figure 1, one end of the housing 100 may also be provided with an end cover 110, which is fixed and sealed to the housing 100, and the second shaft section of the rotating shaft 400 passes through the end cover 110 and extends out. It should be noted that the end cover 110 can also be provided as a whole with the housing 100, but based on factors such as subsequent maintenance, as a typical embodiment, the end cover 110 is connected to the housing 100 through a detachable fixed sealing connection structure / method known in the art. Specifically, in order to maintain the sealing inside the underwater propulsion motor, the rotating shaft 400 is sealed with the housing 100 / end cover 110 through a mechanical dynamic sealing structure 700. It should be noted that the rotating shaft 400 and the mechanical dynamic sealing structure 700 remain fixed in the radial direction, but are movably matched in the axial direction. More specifically, the second shaft section of the rotating shaft 400 is matched with the mechanical dynamic sealing structure 700. More specifically, the mechanical dynamic sealing structure 700 can be set in the cavity inside the shell 100 or in the end cover 110. The mechanical dynamic sealing structure 700 can be fixedly assembled on the shell 100 / end cover 110 through a structure / method known in the art. It can be understood that there is a gap-free fit between the mechanical dynamic sealing structure 700 and the shell 100 / end cover 110.

[0050] Specifically, in order to make the propulsion motor control more precise, a resolver encoder with the same number of pole pairs as the rotor 300 can also be set in the end cover 110. The resolver encoder is used to monitor the working status of the motor. The structure of the resolver encoder itself and the configuration structure between it and other components can be implemented in a manner known in the art and are not specifically limited here.

[0051] It should be noted that with the dynamic changes in diving depth, the pressure difference between the motor interior and the external environment fluctuates significantly, causing a sharp decline in the reliability of the sealing structure. In particular, dynamic sealing parts are prone to micro-gaps due to material fatigue or deformation, causing insulation oil leakage, which in turn causes problems such as deterioration of the motor's internal insulation performance and reduced heat dissipation efficiency. In severe cases, it may even lead to winding short circuits or permanent magnet demagnetization, threatening the safe operation of the spacecraft. Based on this, please refer again to Figure 1 and Figure 2The propulsion motor also includes a pressure compensation mechanism 900, which is axially arranged at one end of the housing 100, specifically the end facing away from the propeller. The pressure compensation mechanism 900 can generate a pressure greater than the external environment in the insulating oil inside the propulsion motor. Specifically, the pressure compensation mechanism 900 includes a compensator body 910 and an elastic element 920. The compensator body 910 is sealed with the housing 100. A sealed accommodating space is provided inside the compensator body 910. The side of the compensator body 910 facing the inner cavity is an elastic diaphragm 930. The elastic diaphragm 930 is in direct contact with the insulating oil in the inner cavity. The elastic element 920 is arranged in the sealed accommodating space and is connected to or in contact with the elastic diaphragm 930. The elastic element 920 is in an elastically compressed state. The elastic diaphragm 930 can deform axially under the action of an external force, wherein the external force includes the elastic force of the elastic element 920 and the pressure of the insulating oil.

[0052] Specifically, the axis of the elastic element 920 is parallel to the axis of the rotating shaft 400, and the aspect ratio of the elastic element 920 is , the pressure compensation mechanism 900 satisfies:

[0053] ;

[0054] Where m is the mass of the elastic element, c is the damping of the elastic element, t is the duration of deformation of the elastic element, A is the effective pressure-bearing area of ​​the pressure compensation mechanism 900, P is the insulating oil in the inner cavity of the housing, k is the stiffness of the elastic element 920, and x is the deformation of the elastic element 920. Illustratively, the elastic element 920 comprises a spring. Specifically, the pressure compensation mechanism 900 maintains the pressure differential between the propulsion motor and the external environment through the elastic force of the elastic element 920. That is, through the interaction between the elastic element 920 (spring) and the fluid pressure, a dynamic balance of pressure within the propulsion motor is achieved. This ensures the stability of the movement of the elastic element 920, thereby maintaining the internal and external pressure differential of the propulsion motor and reducing vibration. The pressure of the insulating oil inside the propulsion motor acts on each component, which is equivalent to applying a force to each component. This force is equivalent to applying an elastic constraint to each component, which can achieve a vibration reduction effect.

[0055] Specifically, the pressure compensation mechanism 900 also includes a diaphragm pressure cover 940, which is axially arranged between the elastic element 920 and the elastic diaphragm 930, and is respectively connected or in contact with the elastic element 920 and the elastic diaphragm 930. The elastic element 920 exerts its elastic force on the elastic rubber diaphragm through the diaphragm pressure cover 940. The effective pressure-bearing area of ​​the pressure compensation mechanism 900 is the contact area between the diaphragm pressure cover 940 and the elastic diaphragm 930.

[0056] Specifically, the static components of the underwater propulsion motor provided in the embodiments of the present invention can be sealed using an O-ring. The compression and extension of the O-ring are calculated to achieve the optimal sealing effect. The stator 200 is loosely fitted with the flange, and two O-rings are used between the two components to form a two-stage seal. This gradually reduces the seawater pressure and effectively enhances the sealing performance of the stator 200. The rotating components of the underwater propulsion motor provided in the embodiments of the present invention are sealed using a stable mechanical dynamic seal, thereby ensuring the overall sealing performance of the propulsion motor. For example, a mechanical dynamic seal structure is used to provide a rotary seal between the stator 200 and the rotor 300 of the propulsion motor. The mechanical dynamic seal structure shifts the sealing area to the well-controlled surfaces of the static and dynamic rings (both of which are part of the mechanical dynamic seal structure). The dynamic ring, pushed by a spring, generates a pressure differential with the static ring that is greater than the external pressure, thereby achieving a rotary seal for the propulsion motor. It should be noted that mechanical dynamic seal structures and the use of mechanical dynamic seal structures to achieve dynamic sealing between motor components are well known in the art, and the specific structural composition of the mechanical dynamic seal structure is not limited herein.

[0057] Specifically, the propulsion motor cable uses a dedicated underwater cable 800, which is specially sealed. An O-ring is placed over the cable 800, and a gland is placed over the O-ring. The tightening force of the screw forces the O-ring to deform, allowing the O-ring to firmly press against the motor cable and the workpiece, forming a secure seal. Cable 800 is commercially available, and its specific structure and product model are not specified here.

[0058] Before the propulsion motor is launched into the water, the present invention fills the interior of the propulsion motor with insulating oil. As the insulating oil rushes in, the internal pressure will increase. The increased pressure will force the elastic element of the pressure compensation mechanism to compress and deform until the elastic element reaches a certain deformation amount. At this time, the injection of insulating oil is stopped, the oil filling port is closed, and the propulsion motor maintains a certain pressure and a certain pressure difference between the inside and the outside. At this time, the propulsion motor can be launched into the water for operation. Even if the propulsion motor has some oil leakage at the mechanical dynamic sealing structure, the elastic element of the pressure compensation mechanism will maintain the pressure difference between the inside and the outside of the propulsion motor, thereby ensuring the sealing of the propulsion motor.

[0059] The present invention integrates the pressure compensation mechanism in the propulsion motor and injects insulating oil with a certain pressure into the propulsion motor, forcing the elastic element in the pressure compensation mechanism to maintain a certain deformation, thereby maintaining a certain pressure in the propulsion motor and a certain pressure difference between the inside and the outside. In particular, the internal and external pressure difference generated by the pressure compensation mechanism on the propulsion motor is smaller than the specific pressure generated by the mechanical dynamic sealing structure, thereby effectively ensuring the sealing of the propulsion motor at different diving depths and reducing or eliminating the leakage of the insulating oil medium.

[0060] 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 and low-noise underwater propulsion motor, characterized by: The invention comprises a stator, a rotor, two radial sliding bearings, and a thrust sliding bearing installed in the inner cavity of the housing. The stator is sleeved on the rotor, and the rotor is connected to a rotating shaft. The rotating shaft is rotatably engaged with the housing through the radial sliding bearing and the thrust sliding bearing respectively. The rotating shaft is sealed with the first end of the housing through a mechanical dynamic seal structure. The rotating shaft is also fixedly connected to a propeller disposed outside the housing. In addition, the inner cavity of the housing is also filled with insulating oil having a set pressure, and the set pressure is greater than the ambient pressure outside the housing. In addition, the propulsion motor also includes a pressure compensation mechanism, which is axially arranged at the second end of the shell, and the pressure compensation mechanism includes a compensator body and an elastic element. The compensator body is sealed with the shell, and a sealed accommodating space is provided in the compensator body. The side of the compensator body facing the inner cavity is an elastic diaphragm, and the elastic diaphragm is in direct contact with the insulating oil in the inner cavity. The elastic element is arranged in the sealed accommodating space and is connected or in contact with the elastic diaphragm. The elastic element is in an elastic compression state, and the elastic diaphragm can be deformed axially under the action of external force, wherein the external force includes the elastic force of the elastic element and the pressure of the insulating oil. The gap between the radial sliding bearing and the rotating shaft is an annular gap, and the width of the annular gap is D / 1000~2D / 1000, and D is the outer diameter of the radial sliding bearing.

2. The low-vibration and low-noise underwater propulsion motor according to claim 1, characterized in that: The axis of the elastic element is parallel to the axis of the rotating shaft, and the aspect ratio of the elastic element is , the pressure compensation mechanism satisfies: ; Where m is the mass of the elastic element, c is the damping of the elastic element, t is the duration of deformation of the elastic element, A is the effective pressure-bearing area of ​​the pressure compensation mechanism, P is the pressure of the insulating oil in the inner cavity of the shell, k is the stiffness of the elastic element, and x is the deformation of the elastic element.

3. The low-vibration and low-noise underwater propulsion motor according to claim 1 or 2, characterized in that: The pressure compensation mechanism also includes a diaphragm cover, which is axially arranged between the elastic element and the elastic diaphragm, and is connected or in contact with the elastic element and the elastic diaphragm respectively. The elastic element applies its elastic force to the elastic rubber diaphragm through the diaphragm cover. The effective pressure-bearing area of ​​the pressure compensation mechanism is the contact area between the diaphragm cover and the elastic diaphragm.

4. The low-vibration and low-noise underwater propulsion motor according to claim 1, characterized in that: The two radial sliding bearings and the thrust sliding bearing are arranged at intervals along the axial direction. The thrust sliding bearing is located on the side of the radial sliding bearing close to the pressure compensation mechanism. One end of the rotating shaft passes through a radial sliding bearing and is inserted into the thrust sliding bearing, and cooperates with the thrust sliding bearing to form a clamping structure.

5. The low-vibration and low-noise underwater propulsion motor according to claim 4, characterized in that: The thrust sliding bearing is a tilting pad bearing.

6. The low-vibration and low-noise underwater propulsion motor according to claim 4, characterized in that: A thrust plate is also fixedly provided on the rotating shaft, and the thrust plate is in contact with or connected to the thrust sliding bearing.

7. The low-vibration and low-noise underwater propulsion motor according to claim 1 or 4, characterized in that: The gap between the stator and the rotor is connected to the inner cavity of the housing, the insulating oil fills the inner cavity of the housing, and part of the insulating oil is filled between the rotating shaft and the radial sliding bearing, between the rotating shaft and the thrust sliding bearing, and in the gap of the radial sliding bearing, thereby forming a pressure-bearing oil film.

8. The low-vibration and low-noise underwater propulsion motor according to claim 7, characterized in that: The pressure-bearing oil film between the radial sliding bearing and the rotating shaft is a wedge-shaped oil film structure. When the rotor rotates, the pressure of the wedge-shaped oil film structure increases as the speed of the rotor increases.

9. The low-vibration and low-noise underwater propulsion motor according to claim 1 or 4, characterized in that: Two bearing supports are fixedly provided in the housing. Each bearing support is correspondingly provided on the periphery of a radial sliding bearing. The bearing support is movably matched with the radial sliding bearing and is used to limit the axial movement of the radial sliding bearing.

10. The low-vibration and low-noise underwater propulsion motor according to claim 9, characterized in that: The two radial sliding bearings are defined as a first radial sliding bearing and a second radial sliding bearing. The first radial sliding bearing is axially located between the pressure compensation mechanism and the second radial sliding bearing. The first radial sliding bearing is a straight cylindrical structure, and the second radial sliding bearing is an L-shaped cylindrical structure.

11. The low-vibration and low-noise underwater propulsion motor according to claim 9, characterized in that: The first end of the shell is sealed with an end cover, and the mechanical dynamic sealing structure is arranged in the end cover.

12. The low-vibration and low-noise underwater propulsion motor according to claim 11, characterized in that: A resolver encoder is also installed in the end cover for monitoring the working state of the motor. The resolver encoder and the rotor have the same number of pole pairs.

13. The low-vibration and low-noise underwater propulsion motor according to claim 1, characterized in that: The rotating shaft includes a first shaft segment and a second shaft segment fixedly connected along the axial direction, the first shaft segment is composed of a magnetic metal material and serves as a rotor core, the second shaft segment is composed of a corrosion-resistant material, the first shaft segment is entirely arranged in the shell, and the second shaft segment is partially arranged outside the shell.

14. The low-vibration and low-noise underwater propulsion motor according to claim 1, characterized in that: The compensator body is entirely embedded in the shell, and the tail of the compensator body is circumferentially and hermetically connected to the second end of the shell.

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