Small underwater shaftless propeller

Abstract

The invention relates to an underwater propeller, in particular to a small underwater shaftless propeller which comprises a shell, a motor assembly, an upper cover and a lower cover, a water inlet and a water outlet are formed in the middle of the lower cover and the middle of the upper cover respectively, the motor assembly comprises a stator and a rotor, propeller blades are arranged in the rotor, the stator is annular and is arranged in a sealing sleeve, and the sealing sleeve is arranged in the shell. One end of the sealing sleeve is opened, and the opening is covered and sealed by the upper cover to form a sealed cavity; water permeable holes are formed in the lower cover close to the water inlet and the upper cover close to the water outlet, the water inlet and the water outlet are each provided with a structural part, a sliding bearing assembly is arranged between the structural parts and the rotor, a gap I is formed in the sliding bearing assembly, and the gap I and the water permeable holes are communicated to form a water lubrication passage; a gap II is formed between the outer peripheral wall of the rotor and the inner ring wall of the sealing sleeve; and the gap II is communicated with the water permeable hole to form a water cooling passage. The device has the characteristics of high reliability, long service life and low maintenance cost, and is suitable for being applied to an underwater environment.

Description

Technical Field

[0001] The invention belongs to the technical field of marine engineering and relates to an underwater propeller, in particular to a small underwater shaftless propeller. Background Art

[0002] At present, shaftless propulsion is mainly composed of blades, motor rotor, multi-pole stator, water-lubricated bearing, guide cover shell, etc. Compared with traditional propeller propulsion, shaftless propulsion has the advantages of high efficiency, less cabin space, low noise and small vibration, and is mostly used in marine scientific research, underwater resource detection and other fields. Therefore, shaftless propulsion is required to be able to seal and waterproof the inside of the propulsion and ensure the smooth rotation of the rotor.

[0003] The patent with announcement number CN110450932A discloses a small underwater propeller, which is sealed and waterproof by plastic sealing and glue pouring. For propellers that work underwater for a long time, this method has poor durability and weather resistance, and it is easy to have glue failure and leakage, because plastic sealing and glue pouring are one-time waterproof methods, and once they fail, it is difficult to repair. In addition, although the glue pouring sealing method ensures that the interior of the small underwater propeller mentioned in the patent is completely isolated from water, this will cause dry grinding of the sliding bearings during operation. Dry grinding will reduce the life of the bearings, and the large dry grinding resistance will also reduce the overall efficiency of the propeller; and dry grinding generates serious heat, and the sealant is affected by high temperature for a long time, which will accelerate aging, resulting in seal failure, and thus making the propeller unusable.

[0004] Therefore, providing a method for effectively ensuring the waterproofing of the interior of the propeller and the smooth rotation of the rotor is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The technical problem to be solved by the present invention is: in order to solve the problems of poor sealing effect and uneven rotor rotation of underwater shaftless propellers in the prior art, a small underwater shaftless propeller is provided, which adopts a sealing sleeve to seal the stator to ensure the waterproof effect, arranges a sliding bearing assembly and lubricates it with water to ensure smooth rotation of the rotor, simplifies the structure and is easy to install.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a small underwater shaftless propeller, including a shell and a motor assembly located in the shell, the two ends of the shell are respectively provided with an upper cover and a lower cover, the middle parts of the lower cover and the upper cover are respectively provided with through holes to form a water inlet and a water outlet, the motor assembly includes a stator and a rotor, the stator is located on the radial outer side of the rotor, and the rotor is provided with propeller blades inside. The stator is annular and is disposed in a sealing sleeve, one end of the sealing sleeve is open and the opening is covered and sealed by an upper cover to form a sealed cavity; A water permeable hole is provided on the lower cover near the water inlet and the upper cover near the water outlet. A structural member is provided on the water inlet and the water outlet respectively. A sliding bearing assembly is provided between the structural member and the rotor. A gap I is provided inside the sliding bearing assembly. The gap I is connected with the water permeable hole to form a water lubrication passage. There is a gap II between the outer peripheral wall of the rotor and the inner ring wall of the sealing sleeve, and the gap II is connected with the water permeable hole to form a water cooling passage.

[0007] The stator is located radially outside the rotor, forming a compact annular structure and optimizing space utilization; the stator is sealed in the sealing sleeve to form a sealed cavity, which effectively isolates water from the motor assembly, prevents water from entering the motor, avoids short circuits and corrosion, and improves the reliability and service life of the motor assembly. The rotor and the sliding bearing assembly are lubricated through a water lubrication passage (gap I), using the fluidity of water to reduce friction and wear. The gap II between the rotor and the sealing sleeve forms a water cooling passage, which uses water flow to take away the heat generated by the motor assembly during operation, effectively reducing the motor temperature, improving the efficiency and stability of the motor, and being able to maintain a good working condition under high load and long-term operation. In addition, the combination of water lubrication and water cooling reduces direct contact and friction between mechanical components and reduces operating noise.

[0008] According to one embodiment of the present invention, the sealing sleeve is in a hollow cylindrical shape, and its peripheral wall has an inner ring wall and an outer ring wall. One end of the outer ring wall and the inner ring wall are connected to form a stator slot of a circular ring structure, and the stator is tightly fitted in the stator slot.

[0009] The stator fits tightly in the stator slot, avoiding the complex assembly structure of traditional motors and improving structural stability. The hollow cylindrical sealing sleeve provides better space for motor heat dissipation, which is conducive to the conduction and dissipation of heat, thereby improving the operating efficiency and stability of the motor; it can withstand the high-pressure environment of the deep sea, while reducing the corrosion of seawater to the motor, and improving the adaptability of the thruster in complex underwater environments.

[0010] According to an embodiment of the present invention, a wire outlet is provided on one end of the outer ring wall away from the opening. The wire outlet is provided to facilitate the lead-out of the stator winding lead wire and prevent the lead wire from being damaged or water from seeping in.

[0011] According to an embodiment of the present invention, the edges of the inner annular wall and the outer annular wall corresponding to the opening are folded inwards and outwards respectively to form folded edges. The folded edges enhance the structural strength of the sealing sleeve and provide a support surface for the subsequent installation of the sealing ring.

[0012] According to one embodiment of the present invention, the upper cover is provided with a groove I and a groove II, and a convex portion is formed between the groove I and the groove II to tightly fit with the opening of the sealing sleeve. The design of the groove I and the groove II makes the upper cover and the sealing sleeve fit more tightly, further improving the sealing performance.

[0013] According to an embodiment of the present invention, a first sealing ring is provided in the groove I, and the folded edge of the outer ring wall is in close contact with the first sealing ring; a second sealing ring is provided in the groove II, and the folded edge of the inner ring wall is in close contact with the second sealing ring. The double sealing ring design enhances the sealing effect and prevents water from penetrating from the connection between the sealing sleeve and the upper cover.

[0014] According to an embodiment of the present invention, the inner wall of the shell is tightly against the outer ring wall of the sealing sleeve, and the edge of the inner wall of the shell presses the folded edge of the outer ring wall. The tight fit between the shell and the sealing sleeve further enhances the stability and sealing of the overall structure.

[0015] According to one embodiment of the present invention, the sliding bearing assembly includes a first sliding bearing and a second sliding bearing, the first sliding bearing is in a circular ring structure and one end of the first sliding bearing is folded toward the center to form a notch, the second sliding bearing is in a circular ring structure and is placed in the notch, and the two are in contact with each other and have a gap I. The dual sliding bearing design improves the support stability of the rotor, and the gap I provides a flow space for water lubrication.

[0016] According to an embodiment of the present invention, annular grooves for accommodating the first sliding bearing are provided at both ends of the rotor, and the first sliding bearing is tightly fitted in the annular grooves. The annular groove design makes the connection between the first sliding bearing and the rotor more stable, reducing vibration and wear.

[0017] According to one embodiment of the present invention, a boss is formed on the outer wall of the structural member, and the inner wall of the second sliding bearing is tightly fitted on the outer wall on one side of the boss and is limited by the boss. The boss design limits the position of the second sliding bearing, prevents it from axial movement, and improves the stability of the bearing.

[0018] According to an embodiment of the present invention, the outer wall of the other side of the boss cooperates with the inner wall of the upper cover or the lower cover. The cooperation between the boss and the upper cover or the lower cover further enhances the integrity and stability of the structure.

[0019] According to one embodiment of the present invention, the first sliding bearing is a ceramic bearing, and the second sliding bearing is a graphite bearing. The ceramic bearing has high hardness and wear resistance, and the graphite bearing has good self-lubricating properties. Water enters between the ceramic bearing and the graphite bearing through the water permeable holes to prevent dry grinding of the bearings and increase the service life of the bearings.

[0020] According to an embodiment of the present invention, the stator is a plastic-encapsulated stator, which has good waterproof and insulating properties and is suitable for use in underwater environments.

[0021] According to an embodiment of the present invention, a plurality of propeller blades are evenly distributed inside the rotor, and the propeller blades and the rotor are connected by gluing or tight fitting or are integrally formed. The even distribution of the propeller blades improves propulsion efficiency, and a variety of optional connection methods provide manufacturing flexibility.

[0022] According to an embodiment of the present invention, the housing is provided with a wire outlet hole, and the upper cover and the lower cover are connected to the housing by fastening screws. The wire outlet hole facilitates the extraction of external wiring leads of the motor stator, and the fastening screw connection method facilitates disassembly and maintenance.

[0023] According to an embodiment of the present invention, the outer end surface of the upper cover and / or the lower cover is an arc surface. The arc surface design reduces water flow resistance and improves the fluid dynamics performance of the propeller.

[0024] Beneficial effects of the present invention: (1) High sealing performance: The sealing sleeve, sealing ring and folded edge design effectively prevent water from penetrating into the motor; (2) Efficient lubrication and cooling: Water lubrication and cooling channels formed by water permeable holes and gaps reduce mechanical wear and overheating problems; (3) Structural stability: The design of sliding bearing assembly, boss and ring groove enhances the support and stability of the rotor, ensuring smooth rotation of the rotor. (4) Convenience of manufacturing and maintenance: Wire outlet holes, fastening screw connections and other methods facilitate manufacturing, installation and maintenance; (5) High performance: Ceramic bearings, graphite bearings and arc surface design improve the durability and fluid dynamics performance of the thruster.

[0025] The small underwater shaftless propeller of the present invention has the characteristics of high reliability, long life and low maintenance cost, and is suitable for application in underwater environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0027] Figure 1 It is a stereoscopic diagram of the first embodiment of the small underwater shaftless propeller of the present invention.

[0028] Figure 2 It is a cross-sectional view of the first embodiment of the small underwater shaftless propeller of the present invention.

[0029] Figure 3 It is an exploded view of the first embodiment of the small underwater shaftless propeller of the present invention.

[0030] Figure 4 It is a cross-sectional view of an assembly diagram of a first embodiment of a small underwater shaftless propeller of the present invention.

[0031] Figure 5 It is a schematic structural diagram of the upper cover in Embodiment 1 of the small underwater shaftless propeller of the present invention.

[0032] Figure 6 It is a cross-sectional view of the sealing sleeve in the first embodiment of the small underwater shaftless propeller of the present invention.

[0033] Figure 7 It is an assembly diagram of the rotor and the sliding bearing assembly in the first embodiment of the small underwater shaftless propeller of the present invention.

[0034] Figure 8 It is an assembly diagram of the structural parts and the second sliding bearing in the first embodiment of the small underwater shaftless propeller of the present invention.

[0035] Fig. 9 It is an assembly diagram of the rotor, sliding bearing assembly and structural parts in the first embodiment of the small underwater shaftless propeller of the present invention.

[0036] Fig.10 It is an assembly diagram of the structural parts and the lower cover in the first embodiment of the small underwater shaftless propeller of the present invention.

[0037] Fig.11 It is an assembly diagram of the upper cover and the first sealing ring and the second sealing ring in the first embodiment of the small underwater shaftless propeller of the present invention.

[0038] Fig.12 It is an assembly diagram of the housing, sealing sleeve, upper cover and structural parts in the first embodiment of the small underwater shaftless propeller of the present invention.

[0039] Fig.13 It is a cross-sectional view of the upper cover in the second embodiment of the small underwater shaftless propeller of the present invention.

[0040] Fig.14 It is a cross-sectional view of the lower cover in the third embodiment of the small underwater shaftless propeller of the present invention.

[0041] In the figure: 1. upper cover; 11. water outlet; 12. water permeable hole; 2. outer shell; 21. wire outlet hole; 3. lower cover; 31. water inlet; 4. fastening screws; 5. stator; 6. rotor; 61. ring groove; 7. propeller blade; 8. structural part; 81. boss; 9. sealing sleeve; 90. stator groove; 91. inner ring wall; 92. outer ring wall; 93. wire outlet; 13. first sliding bearing; 14. second sliding bearing; 15. groove I1; 16. groove II; 17. first sealing ring; 18. second sealing ring. DETAILED DESCRIPTION

[0042] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0043] Embodiment 1 like Figure 1 As shown, the small underwater shaftless propeller of this embodiment is divided into an upper cover 1, a shell 2 and a lower cover 3 in terms of appearance and structure. The upper cover 1 and the lower cover 3 are respectively arranged at both ends of the shell 2. Among them, circular through holes are provided in the center of the upper cover 1 and the lower cover 3, respectively forming a water outlet 11 in the middle of the upper cover 1 and a water inlet 31 in the middle of the lower cover 3. The upper cover 1 and the lower cover 3 are fixed to the shell 2 by fastening screws 4. A plurality of water-permeable holes 12 are provided at the position of the upper cover 1 near the water outlet 11. When working underwater, water enters the interior of the shaftless propeller through the water-permeable holes 12 to lubricate the internal sliding bearings. A wire outlet hole 21 is provided on the shell 2 to lead out the external wires of the stator 5.

[0044] like Figure 2 to Figure 4 As shown, a motor assembly is arranged in the housing 2, and the motor assembly includes a stator 5 and a rotor 6. The stator 5 is located radially outside the rotor 6, and a propeller blade 7 is arranged inside the rotor 6. A structural member 8 is arranged at each end of the rotor 6, and the two structural members 8 are respectively located on the water outlet 11 and the water inlet 31, and the function is to limit the rotor 6 in the axial direction to prevent the rotor 6 from moving in the axial direction when the motor assembly is working. A sliding bearing assembly is arranged between the structural member 8 and the rotor 6, and a gap I is arranged inside the sliding bearing assembly, and the gap I is connected with the water permeable hole 12 to form a water lubrication passage (such as Figure 2 (indicated by the solid arrow in the middle).

[0045] The stator 5 is annular and is disposed in a sealing sleeve 9. One end of the sealing sleeve 9 is open and the opening is covered and sealed by the upper cover 1 to form a sealed cavity. There is a gap II between the outer peripheral wall of the rotor 6 and the inner ring wall 91 of the sealing sleeve 9. The gap II is connected to the water permeable hole 12 to form a water cooling passage (such as Figure 2 (indicated by the dashed arrow in the middle).

[0046] The sliding bearing assembly includes a first sliding bearing 13 and a second sliding bearing 14. The first sliding bearing 13 is in a circular ring structure and one end of the first sliding bearing 13 is folded toward the center to form a notch. The second sliding bearing 14 is in a circular ring structure and is placed in the notch. The two are in contact with each other and have a gap I. Both ends of the rotor 6 are provided with annular grooves 61 for accommodating the first sliding bearing 13. The first sliding bearing 13 is tightly fitted in the annular grooves 61. A boss 81 is protruded from the outer wall of the structural member 8. The inner wall of the second sliding bearing 14 is tightly fitted on the outer wall of one side of the boss 81 and is limited by the boss 81.

[0047] The first sliding bearing 13 is installed in the annular groove 61 at both ends of the rotor 6. The inner wall of the first sliding bearing 13 is tightly matched with the outer wall of the rotor 6 and axially abuts against the rotor 6. When the motor assembly is working, the first sliding bearing 13 is transported with the rotor 6. The second sliding bearing 14 is installed on the structural member 8. The inner wall of the second sliding bearing 14 is tightly matched with the outer wall of one end of the structural member 8 and axially abuts against the radial boss 81 in the middle of the structural member 8. When the motor assembly is working, the second sliding bearing 14 remains fixed. As a result, there will be relative movement between the first sliding bearing 13 and the second sliding bearing 14. Water enters between the first sliding bearing 13 and the second sliding bearing 14 through the water permeable hole 12, which can prevent the two sliding bearings from dry grinding and increase the service life of the two sliding bearings.

[0048] like Figure 5 As shown, propeller blades 7 are evenly distributed inside the rotor 6. The propeller blades 7 and the rotor 6 are an integral structure, and the two can be connected by adhesive or tight fit or integrally formed. When the shaftless propeller is working, the rotor 6 drives the propeller blades 7 to rotate, generating thrust to push the underwater device forward.

[0049] like Figure 6 As shown, the sealing sleeve 9 is in the shape of a hollow cylinder, and its circumferential wall has an inner ring wall 91 and an outer ring wall 92. The outer ring wall 92 and one end of the inner ring wall 91 are connected to form a stator slot 90 of a circular ring structure, and the stator 5 fits tightly in the stator slot 90. An outlet 93 is provided on the end of the outer ring wall 92 of the stator slot 90 away from the opening, which is convenient for leading out the stator winding. At the end of the sealing sleeve 9 close to the outlet 93, the inner ring wall 91 and the outer ring wall 92 are connected together to form a U-shaped structure, while the other ends of the inner ring wall 91 and the outer ring wall 92 are separated to form an opening, which is convenient for placing the stator 5 into the stator slot 90. In this embodiment, the stator 5 adopts a plastic-encapsulated stator, which has good waterproof and insulating properties. When the small underwater shaftless propeller is working, such as Figure 2 As shown, water flows in from the water-permeable hole 12, and flows through the sealing sleeve 9 from the end with the outlet 93 through the channel surrounded by the inner annular wall 91. The inner annular wall 91 is between the water and the stator 5, separating the water and the stator 5, that is, protecting the stator 5 winding. At the same time, the water takes away the heat generated by the winding, achieving a liquid cooling effect. The edges of the corresponding openings of the inner annular wall 91 and the outer annular wall 92 are folded inwardly and outwardly to form folded edges.

[0050] like Figure 7 As shown, annular grooves 61 are provided at both ends of the rotor 6, and the first sliding bearings 13 are respectively installed in the annular grooves 61 at both ends of the rotor 6, and the outer wall of the first sliding bearing 13 is tightly matched with the inner wall of the annular groove 61, and the first sliding bearing 13 and the propeller blade 7 rotate with the rotor 6; the first sliding bearing 13 has a flange toward the center at one end close to the rotor 6, as shown in FIG. Figure 2As shown, the cross-sectional view of the first sliding bearing 13 is L-shaped, forming a groove for accommodating the second sliding bearing 14 .

[0051] Specifically, in the axial direction, the first sliding bearing 13 is placed in the annular groove 61 of the rotor 6, and the end of the first sliding bearing 13 close to the propeller blade 7 in the axial direction abuts against the annular groove 61 of the rotor 6; in the radial direction, the end of the first sliding bearing 13 facing radially outward abuts against the annular groove 61, that is, the first sliding bearing 13 and the annular groove 61 are radially tightly fitted as one. The second sliding bearing 14 is placed in the notch of the first sliding bearing 13, and the outer periphery of the second sliding bearing 14 and the inner periphery of the first sliding bearing 13 are a loose fit that is quasi-contacting but non-contacting, and the two rotate relative to each other. During operation, the first sliding bearing 13 is transported with the rotor 6, and the second sliding bearing 14 is fixed, so the inner circumferential surface of the first sliding bearing 13 and the outer circumferential surface of the second sliding bearing 14 will rub.

[0052] like Figure 8 and Fig. 9 As shown, the second sliding bearing 14 is a circular ring structure, one end of the structural member 8 is inserted into the inner wall of the second sliding bearing 14 and the two are radially tightly matched, and a boss 81 is arranged on the outer periphery of the structural member 8 to play a role of limiting and axial fixing, and then the fastening fittings of the structural member 8 and the second sliding bearing 14 are inserted into the notch of the first sliding bearing 13. In this embodiment, the first sliding bearing 13 preferably adopts a ceramic bearing, and the second sliding bearing 14 preferably adopts a graphite bearing. When the shaftless propeller is working, the structural member 8 and the second sliding bearing 14 are fixed, and relative motion occurs between the first sliding bearing 13 and the second sliding bearing 14. The graphite powder and water generated by the mutual friction between the two play a role of lubrication. At the same time, the structural member 8 also plays a radial supporting role, supporting the first sliding bearing 13, the second sliding bearing 14 and the rotor 6 to keep the axial and radial positions fixed, and the four form a concentric structure.

[0053] Specifically, the outer circumferential surface of the structural member 8 abuts against and fits tightly against the inner circumferential surface of the second sliding bearing 14, and the structural member 8 supports the second sliding bearing 14 in the radial direction to ensure that the second sliding bearing 14 remains fixed during operation; at the same time, the boss 81 on the middle outer periphery of the structural member 8 plays an axial limiting role. When the second sliding bearing 14 is pressed into the structural member 8, the boss 81 contacts the second sliding bearing 14, indicating that it is pressed into place.

[0054] The structural member 8 is divided into two ends by the boss 81, one end is tightly matched with the second sliding bearing 14, and the other end is fixed by the upper cover 1 or the lower cover 3, which can ensure that the structural member 8 remains fixed during operation. Fig.10 As shown, during assembly, the boss 81 of the structural member 8 axially abuts and overlaps with the inner wall structure of the lower cover 3 axially. At this time, the lower edge of the boss 81 is just flush with the edge of the lower cover 3, which plays an axial positioning role during installation.

[0055] like Fig.11 As shown, the upper cover 1 is provided with a groove I15 and a groove II16, and a convex portion is formed between the groove I15 and the groove II16 to tightly fit with the opening of the sealing sleeve 9. A first sealing ring 17 is provided in the groove I15, and the folded edge of the outer ring wall 92 of the sealing sleeve 9 is tightly against the first sealing ring 17; a second sealing ring 18 is provided in the groove II16, and the folded edge of the inner ring wall 91 is tightly against the second sealing ring 18. Adding two sealing rings to the upper cover 1 improves the overall sealing and waterproof effect of the shaftless propeller. Fig.10 During assembly, the structural member 8 is installed into the upper cover 1, and the sealing sleeve 9 is installed. The upper edge of the outer wall of the sealing sleeve 9 abuts against the first sealing ring 17, and the upper edge of the inner wall abuts against the second sealing ring 18, forming a static sealing structure with good sealing effect.

[0056] like Figure 2 As shown, the inner wall of the housing 2 is pressed against the outer ring wall 92 of the sealing sleeve 9, and the edge of the inner wall of the housing 2 is pressed against the folded edge of the outer ring wall 92. The upper cover 1 and the lower cover 3 are connected to the housing 2 by fastening screws 4. When installing the housing 2, align the fastening screw holes of the housing 2 with the fastening screw holes of the upper cover 1 for installation. At this time, the edge of the inner wall of the housing 2 is pressed against the folded edge of the outer ring wall 92. After the upper cover 1 is fixed with the fastening screws 4, the upper edge of the inner wall of the housing 2 and the folded edge of the outer ring wall 92 can press the first sealing ring 17, and the folded edge of the inner ring wall 91 is pressed against the second sealing ring 18, which has a good sealing and waterproofing effect.

[0057] The small underwater shaftless propeller of this embodiment can effectively prevent water from entering the interior of the motor assembly, protect the motor assembly from water erosion, and improve the reliability and service life of the propeller. The design of the sealed cavity can withstand a certain water pressure and is suitable for use in deep water environments, ensuring that the motor assembly can still work normally under high pressure environments. Water enters the gap I through the water-permeable hole 12 to provide lubrication for the sliding bearing, reduce friction loss, and extend the service life of the bearing. The water lubrication passage uses water as a lubricating medium, does not require additional lubricating oil or grease, reduces maintenance requirements, and is particularly suitable for use in underwater environments. The water cooling passage uses water as a cooling medium, does not require an additional cooling system, simplifies the structure of the propeller, and improves the cooling efficiency. Water enters the gap II through the water-permeable hole 12, flows through the motor assembly, takes away the heat generated when the motor is running, and effectively prevents the motor from overheating.

[0058] The arrangement of the water inlet 31 and the water outlet 11 allows water to flow in both directions, and can enter the propeller through the water inlet 31 for lubrication and cooling, and can be discharged through the water outlet 11, ensuring smooth water circulation inside the propeller. The design of the sliding bearing assembly enables the rotor 6 to operate under low friction conditions, reducing energy loss and improving the efficiency of the propeller. The sliding bearing assembly uses water lubrication, which reduces mechanical wear, extends the service life of the bearing, and reduces the maintenance frequency.

[0059] Embodiment 2 like Fig.13 As shown, the difference from the first embodiment is that the outer end surface of the upper cover 1 is an arc surface. The arc surface of the upper cover 1 can effectively slow down the water flow speed, so that the water flow will not be directly sprayed out when flowing out, but will be guided by the arc shape, thereby reducing the impact force of the water flow, and can make the water flow out more evenly, avoiding excessive concentration or dispersion of the water flow.

[0060] Embodiment 3 like Fig.14 As shown, the difference from the first embodiment is that the outer end surface of the lower cover 3 is an arc surface. The arc surface of the lower cover 3 can reduce the water flow resistance. The arc surface of the lower cover 3 can effectively guide the water flow to enter the water inlet 31 more evenly, avoid the water flow from being too concentrated or dispersed, thereby reducing the impact of the water flow; it can reduce the direct impact of the water flow on the water inlet 31, reduce the noise caused by the excessive speed of the water flow, and make the water flow more stable; it can better disperse the water flow pressure, avoid local stress concentration caused by the impact of the water flow, thereby improving the structural strength and durability of the water inlet 31.

[0061] Embodiment 4 The difference from the first embodiment is that the outer end surfaces of the upper cover 1 and the lower cover 3 are both arc surfaces.

[0062] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A small underwater shaftless propeller, comprising a housing (2) and a motor assembly located in the housing (2), wherein an upper cover (1) and a lower cover (3) are respectively provided at both ends of the housing (2), and through holes are respectively provided in the middle of the lower cover (3) and the upper cover (1) to form a water inlet (31) and a water outlet (11), wherein the motor assembly comprises a stator (5) and a rotor (6), wherein the stator (5) is located radially outside the rotor (6), and a propeller blade (7) is provided inside the rotor (6), and wherein: The stator (5) is annular and is disposed in a sealing sleeve (9); one end of the sealing sleeve (9) is open and the opening is covered and sealed by the upper cover (1) to form a sealed cavity; A water permeable hole (12) is provided on the lower cover (3) near the water inlet (31) and the upper cover (1) near the water outlet (11); a structural member (8) is provided on the water inlet (31) and the water outlet (11); a sliding bearing assembly is provided between the structural member (8) and the rotor (6); a gap I is provided inside the sliding bearing assembly; the gap I is connected to the water permeable hole (12) to form a water lubrication passage; A gap II is provided between the outer peripheral wall of the rotor (6) and the inner annular wall of the sealing sleeve (9), and the gap II is connected to the water permeable hole (12) to form a water cooling passage.

2. The small underwater shaftless propeller according to claim 1, characterized in that: The sealing sleeve (9) is in the shape of a hollow cylinder, and its peripheral wall comprises an inner ring wall (91) and an outer ring wall (92). One end of the outer ring wall (92) and the inner ring wall (91) are connected to form a stator slot (90) of a circular ring structure. The stator (5) is tightly fitted in the stator slot (90).

3. The small underwater shaftless propeller according to claim 2, characterized in that: A wire outlet (93) is provided on an end of the outer ring wall (92) away from the opening.

4. The small underwater shaftless propeller according to claim 2, characterized in that: The edges of the corresponding openings of the inner annular wall (91) and the outer annular wall (92) are folded inwards and outwards respectively to form folded edges.

5. The small underwater shaftless propeller according to claim 4, characterized in that: The upper cover (1) is provided with a groove I (15) and a groove II (16), and a convex portion tightly fitting with the opening of the sealing sleeve (9) is formed between the groove I (15) and the groove II (16).

6. The small underwater shaftless propeller according to claim 5, characterized in that: A first sealing ring (17) is arranged in the groove I (15), and the folded edge of the outer ring wall (92) is tightly against the first sealing ring (17); a second sealing ring (18) is arranged in the groove II (16), and the folded edge of the inner ring wall (81) is tightly against the second sealing ring (18).

7. The small underwater shaftless propeller according to claim 6, characterized in that: The inner wall of the outer shell (2) is tightly against the outer annular wall (92) of the sealing sleeve (9), and the edge of the inner wall of the outer shell (1) is pressed against the folded edge of the outer annular wall (92).

8. The small underwater shaftless propeller according to claim 1, characterized in that: The sliding bearing assembly comprises a first sliding bearing (13) and a second sliding bearing (14); the first sliding bearing (13) is in a circular ring structure and one end is folded towards the center to form a notch; the second sliding bearing (14) is in a circular ring structure and is placed in the notch; the two are in contact and have a gap I.

9. The small underwater shaftless propeller according to claim 8, characterized in that: An annular groove (61) for accommodating a first sliding bearing (13) is provided at both ends of the rotor (6), and the first sliding bearing (13) is tightly fitted in the annular groove (61).

10. The small underwater shaftless propeller according to claim 8, characterized in that: A boss (81) is formed protruding from the outer wall of the structural member (8), and the inner wall of the second sliding bearing (14) is tightly fitted on the outer wall of one side of the boss (81) and is limited by the boss (81).

11. The small underwater shaftless propeller according to claim 8, characterized in that: The outer wall of the other side of the boss (81) cooperates with the inner wall of the upper cover (1) or the lower cover (3).

12. The small underwater shaftless propeller according to claim 8, characterized in that: The first sliding bearing (13) is a ceramic bearing, and the second sliding bearing (14) is a graphite bearing.

13. The small underwater shaftless propeller according to claim 1, characterized in that: The stator (5) is a plastic-sealed stator.

14. The small underwater shaftless propeller according to claim 1, characterized in that: A plurality of propeller blades (7) are evenly distributed inside the rotor (6), and the propeller blades (7) and the rotor (6) are connected by gluing or by tight fitting or are integrally formed.

15. The small underwater shaftless propeller according to claim 1, characterized in that: The housing (2) is provided with a wire outlet hole (21), and the upper cover (1) and the lower cover (3) are connected to the housing (2) via fastening screws (4).

16. The small underwater shaftless propeller according to claim 1, characterized in that: The outer end surfaces of the upper cover (1) and / or the lower cover (3) are arc surfaces.

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