A ring-shaped electric propeller supported by a magnetic fluid composite suspension bearing

Abstract

The present invention relates to an annular electric propeller supported by a magnetic fluid composite suspension bearing, comprising: a housing, a rim-type motor, a magnetic fluid composite suspension bearing system and a propeller. The present invention adopts a permanent magnet brushless motor placed in water to directly drive the hubless propeller to rotate, eliminating the intermediate transmission mechanism, and the rotor and propeller assembly are supported by the magnetic fluid composite suspension bearing system and transmit the thrust to the motor and the hull, reducing the intermediate transmission loss between the motor and the propeller, improving efficiency, simplifying the propulsion system structure, reducing noise and vibration, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of marine propellers in ship engines, and in particular relates to an annular electric propeller supported by a magnetic fluid composite suspension bearing. Background Art

[0002] With the development of electric propulsion technology, electric propulsion systems are increasingly being used on ships. Common electric propulsion systems include variable speed gearboxes, shaft systems (including shafts, couplings, various bearings and bearing seats, stern tube seals), propellers, etc. The propulsion method of the electric propulsion system is that the electric motor drives the variable speed gearbox to decelerate, and then drives the shaft system and propeller to rotate, generating thrust for the ship to move forward or backward, such as Figure 1 As shown. This propulsion method has the following problems: complex structure, many parts, high failure rate, large space occupation, heavy weight; low propulsion efficiency: the motor and propeller are transmitted through gears, shaft systems and other components, gear meshing produces energy loss, and the bearings are usually sliding bearings, which have large friction and friction power consumption; the above transmission links produce intermediate transmission losses, reducing the propulsion efficiency of the system; the transmission gear meshing produces vibration and causes noise. Secondly, after the water flows through the shaft system and underwater appendages, turbulence is generated, and the propeller rotates in the turbulent flow, generating excitation and cavitation, and the cavitation bursts to produce noise. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention proposes an annular electric thruster supported by a magnetic fluid composite suspension bearing, which adopts a permanent magnet brushless motor placed in the water to directly drive the hubless propeller to rotate, eliminating the intermediate transmission mechanism. The rotor and propeller assembly are supported by a magnetic fluid composite suspension bearing system and the thrust is transmitted to the motor and the hull, thereby reducing the intermediate transmission loss between the motor and the propeller, improving efficiency, simplifying the propulsion system structure, and reducing noise and vibration.

[0004] In order to solve at least one of the above technical problems, the technical solution adopted by the present invention is:

[0005] A ring-shaped electric propeller supported by a magnetic fluid composite suspension bearing, characterized in that it comprises: a housing, a rim-type motor, a magnetic fluid composite suspension bearing system and a propeller, wherein:

[0006] The rim-type motor comprises: a stator assembly, a rotor assembly and an end face flange, wherein the stator assembly and the rotor assembly are arranged in the housing, and the end face flanges are respectively arranged at both ends of the housing;

[0007] The magnetic fluid composite suspension bearing system is located on the end face flange, and the magnetic fluid composite suspension bearing system includes: a rotor end plate, a thrust plate, a dynamic thrust ring and a static thrust ring. The rotor end plate is connected to the rotor assembly and has a first gap channel between the rotor end plate and the end face flange. A first water flow channel connected to the first gap channel is provided inside the rotor end plate. The thrust plate is fixed to the end of the rotor end plate and has a second gap channel connected to the first gap channel between the rotor end plate and the end face flange. A second water flow channel connected to the second gap channel and the first water flow channel is provided inside the thrust plate, respectively, for water to flow through to form liquid suspension; the dynamic thrust ring is provided on the inner wall of the thrust plate, and the static thrust ring is provided on the outer wall of the end face flange at the position corresponding to the dynamic thrust ring, for generating magnetic repulsion to form magnetic suspension;

[0008] The propeller is connected to the rotor assembly.

[0009] Furthermore, the rotor end plate is also provided with a radial high-pressure water cavity, and the radial high-pressure water cavity is respectively connected with the first gap channel and the first water flow channel for generating radial high-pressure water flow.

[0010] Furthermore, the thrust plate is also provided with an axial high-pressure water chamber and a water inlet. The axial high-pressure water chamber is respectively connected to the second gap channel and the second water flow channel for generating axial high-pressure water flow. The water inlet is connected to the second water flow channel.

[0011] Furthermore, the water inlet is connected to a high-pressure water pump.

[0012] Furthermore, the magnetic fluid composite suspension bearing system further comprises: a friction reducing block, which is arranged on the outer wall of the end face flange.

[0013] Furthermore, the stator assembly is fixed above the inner steps of the end face flanges at both ends, and the rotor assembly is located on the inner side of the stator assembly.

[0014] Furthermore, the propeller is an integral propeller or a split propeller.

[0015] Furthermore, the dynamic thrust ring and the static thrust ring are both permanent magnets or electromagnetic coils wrapped with corrosion-resistant coatings, with the same poles facing each other to generate magnetic repulsion.

[0016] Furthermore, the rim-type motor is a rim-type permanent magnet brushless motor.

[0017] The beneficial effects of the present invention include at least:

[0018] 1) Improved propulsion efficiency: First, a permanent magnet brushless motor is used, which uses permanent magnets instead of coils. Compared with traditional separately excited motors, it reduces current loss and improves motor efficiency and power factor. Second, the inner circle of the motor rotor directly fixes the propeller, and the rotor directly drives the propeller to rotate. No intermediate transmission link is required, eliminating the loss caused by the intermediate transmission link. Third, the magnetic fluid composite suspension bearing system supports the rotor assembly and propeller, bears its weight and thrust, and keeps it in a suspended state during rotation, reducing friction and friction power consumption. The above measures have improved propulsion efficiency.

[0019] 2) Reduced noise and vibration: Since the rotor directly drives the propeller, the vibration and noise caused by the gear meshing of the gearbox in the traditional propulsion type are eliminated; secondly, during the operation of the propeller, the bearing pair is a non-contact magnetic fluid suspension bearing system, which greatly reduces friction noise and vibration. In summary, the noise and vibration are reduced;

[0020] 3) Simplified structure, lighter weight, improved reliability, and less space occupied in the cabin: The intermediate transmission components such as couplings, gearboxes, shaft systems, sliding bearings and bearing seats, stern tube sealing systems, etc. inherent in traditional electric propulsion types have been eliminated, making the structure simpler, more reliable, and significantly lighter in weight. In addition, since the motor is placed underwater, space in the cabin is saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the electric propulsion system of the prior art.

[0022] Figure 2 This is a schematic diagram of the structure of the annular electric thruster of the present invention.

[0023] Figure 3 for Figure 2 CC section view.

[0024] Figure 4 The figure is a schematic diagram of the structure of an integrated propeller according to an embodiment of the present invention.

[0025] Figure 5 The figure is a schematic diagram of the split propeller structure according to an embodiment of the present invention.

[0026] Figure 6 for Figure 3 A partial enlarged view of point A shows the structure of the magnetic fluid composite suspension bearing system.

[0027] Among them, the motor 1, the gear box 2, the shaft system 3, the propeller 4, the blade tip 401, the blade tip flange 402, the blade 403, the rotor assembly 5, the left end face flange 6, the shell 7, the stator assembly 8, the right end face flange 9, the magnetic fluid composite suspension bearing system 10, the rotor end plate 11, the first gap channel 111, the first water flow channel 112, the radial high-pressure water cavity 113, the thrust plate 12, the second gap channel 121, the second water flow channel 122, the axial high-pressure water cavity 123, the water inlet 124, the dynamic thrust ring 13, the static thrust ring 14, the radial friction reducing block 15, and the axial friction reducing block 16. DETAILED DESCRIPTION

[0028] In order to make those skilled in the art better understand the technical scheme of the present invention, the present invention is further described in detail below in conjunction with specific embodiments. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in this area or the product specification are used.

[0029] Figure 2 This is a schematic diagram of the structure of the annular electric thruster of the present invention. Figure 3 for Figure 2 CC section view, combined with Figure 2 and 3 As shown, the annular electric propeller supported by a magnetic fluid composite suspension bearing of the present invention mainly comprises: a housing, a rim-type motor, a propeller and a magnetic fluid composite suspension bearing system.

[0030] The present invention adopts a rim-type permanent magnet brushless motor to replace the traditional separately excited three-phase asynchronous motor. The rim-type motor is mainly composed of a stator assembly, a rotor assembly, a casing, and an end face flange. The motor stator assembly is composed of an iron core and a coil, and is integrally encapsulated with a sealing insulating glue to isolate it from water and play an insulating role. The rotor contains a permanent magnet and is encapsulated with a sealing insulating glue to prevent water from entering the rotor and corroding the permanent magnet. The left and right ends of the rotor are rotor end plates, which together with the rotor form a rotor assembly. The stator core is pressed into the motor casing, and the casing is the shell of the propeller. The left and right ends of the shell are connected to the end face flanges of the motor, which are respectively: a left end face flange and a right end face flange. The stator assembly is fixed above the inner steps of the end face flanges at both ends, and the rotor assembly is located on the inner side of the stator assembly.

[0031] The inner diameter of the rotor of the present invention is large and can accommodate a propeller. The propeller is fixed on the inner circle of the rotor assembly through the blade tip. The rotor directly drives the propeller to rotate. The motor speed is the propeller speed, and no intermediate transmission links such as gears are required. The motor stator generates a rotating magnetic field after a three-phase power supply is connected. The permanent magnet in the motor rotor generates an electromagnetic force under the action of the rotating magnetic field. The rotor rotates and outputs a torque, driving the propeller to rotate in the water to generate thrust to propel the ship.

[0032] The propeller of the present invention is a metal propeller or a composite propeller. The number of propeller blades is determined according to the calculation of hydrodynamic performance, and the number of blades can be 2, 3, 4, 5, 6, etc., and the specific number is not particularly limited.

[0033] Figure 4 FIG. 1 is a schematic diagram of an integrated propeller structure according to an embodiment of the present invention. Figure 4 As shown, the propeller of this embodiment is of an integral type, and the blades are connected as a whole through a common blade tip flange, and then connected to the rotor assembly through the blade tip flange.

[0034] Figure 5 FIG. 1 is a schematic diagram of a split propeller structure according to an embodiment of the present invention. Figure 5 As shown, the propeller blades of this embodiment are split, and each blade is fixed to the inner circle of the rotor assembly through a blade tip flange, and is supported and directly driven by the rotor assembly. At the same time, since the propeller is made into a split type, it is also convenient for disassembly and replacement.

[0035] It can be understood that both integral propellers and split propellers are hubless propellers. Each blade is fixed to the rotor assembly through a blade tip flange and is directly driven by the rotor assembly. The motor speed is the propeller speed. There is no need for a shaft system and hub for support and transmission, nor is there a need for intermediate transmission links such as transmission gears.

[0036] Figure 6 for Figure 3 A partial enlarged view of the A, refer to Figure 6 As shown, the magnetic liquid composite suspension bearing system is located on the end face flange and consists of a liquid suspension bearing system and a magnetic thrust bearing system.

[0037] Among them, the liquid suspension bearing system bears the weight of the rotor assembly and the propeller, and the liquid suspension bearing system is composed of a thrust plate, a friction reducing block, a rotor end plate, and a water flow channel opened in the rotor end plate and the thrust plate. More specifically: the rotor end plate is connected to the rotor assembly and has a first gap channel between the rotor end plate and the end face flange, and a first water flow channel connected to the first gap channel is provided inside the rotor end plate. The thrust plate is fixed to the end of the rotor end plate and has a second gap channel connected to the first gap channel between the rotor end plate and the end face flange, and a second water flow channel connected to the second gap channel and the first water flow channel are provided inside the thrust plate.

[0038] The rotor end plate is also provided with a radial high-pressure water cavity, and the radial high-pressure water cavity is respectively connected with the first gap channel and the first water flow channel for generating radial high-pressure water flow.

[0039] The thrust plate is also provided with an axial high-pressure water chamber and a water inlet. The axial high-pressure water chamber is respectively connected to the second gap channel and the second water flow channel for generating an axial high-pressure water flow. The water inlet is connected to the second water flow channel.

[0040] The friction reducing block is arranged on the outer wall of the end face flange, and includes: a radial friction reducing block and an axial friction reducing block, wherein the radial friction reducing block is located at a relative position of the radial high-pressure water cavity, and the axial friction reducing block is located at a relative position of the axial high-pressure water cavity.

[0041] The working principle of the liquid suspension bearing system described in the present invention is as follows: when the motor starts, the rotor assembly starts to rotate, driving the rotor end plate to rotate, and the thrust plate connected to the rotor end plate then rotates together, and the water at the water inlet of the second water flow channel in the thrust plate is sucked into the second water flow channel in the thrust plate. As the thrust plate and the rotor assembly rotate at high speed, a high-pressure water flow is formed under the work of centrifugal force, and is introduced into the radial high-pressure water cavity inside the thrust plate and the rotor end plate through the waterway (in the direction indicated by the arrow). The water flow velocity decreases, the water pressure increases, and a local high-pressure water area is formed between the radial high-pressure water cavity and the inner circular surface of the matching motor end face flange. The water pressure thrust F1 acts on the inner circular surface of the end face flange to form a supporting force to support the rotor assembly, overcome the gravity of the rotor assembly, lift the rotor assembly, and does not contact the stator assembly. It is in a suspended state, which greatly reduces the sliding friction and reduces the noise.

[0042] When the motor starts to accelerate and stops to decelerate, the centrifugal force weakens, and the supporting force generated by the high-pressure water pressure is not enough to overcome the gravity of the rotor assembly and the propeller. At this time, the rotor end plate contacts the radial friction-reducing block on the end face flange and is in a state of sliding friction. The low friction coefficient and low wear rate of the friction-reducing block make the direct friction pair in a low-resistance friction state, ensuring the reliable operation of the propeller at low speed. High-pressure water can be generated by the centrifugal force brought by the high-speed rotation of the rotor assembly itself, or it can be directly pumped in by a high-pressure water pump connected to an external water inlet.

[0043] The magnetic thrust bearing system consists of a dynamic thrust ring installed in a thrust plate and a static thrust ring in an end face flange corresponding to the position of the dynamic thrust ring, forming a dynamic and static thrust bearing pair. The dynamic thrust ring and the static thrust ring are both permanent magnets or electromagnetic coils wrapped with corrosion-resistant coatings, with the same poles facing each other, generating magnetic repulsion.

[0044] The working principle of the magnetic thrust bearing system is as follows: during the operation of the motor, the propeller drives the rotor assembly and the thrust plate to rotate together, and the propeller thrust pushes the rotor and the thrust plate forward (to the left in the figure), that is, toward the end face flange, so that the gap between the thrust plate and the end face flange becomes smaller. As the gap becomes smaller and smaller, the magnetic repulsion F2 generated between the magnets or between the magnets and the coil becomes larger and larger, and finally reaches a balance with the propeller thrust. The dynamic thrust ring and the static thrust ring maintain a certain gap and are in a non-contact suspension state, avoiding direct sliding friction between the thrust plate and the motor end face flange, thereby greatly reducing heat and wear.

[0045] Reference Figure 6 As shown, the high-pressure water flow generated by high-speed rotation can also be introduced into the axial high-pressure water cavity of the thrust plate, the flow rate is reduced, the water pressure is increased, and in the gap between the axial high-pressure water cavity and the end face flange, the high-pressure water generates a hydraulic thrust F1 to both sides. When the propeller thrust pushes the thrust plate to move toward the end face flange, the gap between the thrust plate and the axial high-pressure water cavity of the end face flange becomes smaller, the water flow rate is lower, and the water pressure is higher, preventing the thrust plate from continuing to approach the end face flange. Finally, the sum of the hydraulic thrust and the magnetic thrust (i.e., the magnetic repulsion F2) reaches a balance with the propeller thrust, and the thrust plate stops moving toward the end face flange, maintaining a certain gap, and the thrust plate and the end face flange are in a non-contact suspension state. This is equivalent to the hydraulic thrust generated by the fluid power sharing part of the axial load of the magnetic thrust bearing, forming a combined force with the magnetic thrust, and jointly offsetting the thrust of the propeller, so that the thrust bearing pair is in a suspended state. This is the principle of generating a liquid-suspended thrust bearing pair through fluid power. The present invention uses a magnetic fluid composite suspension bearing system generated by centrifugal force and magnetic force, which simultaneously plays the role of thrust and radial bearings, eliminates direct friction between the thrust bearing pair and the radial bearing pair, prevents the bearings from wearing out, greatly prolongs the life and reliability of the bearings, and solves the problem of bearing wear of rim-type motors in water.

[0046] The liquid suspension bearing system and the magnetic thrust bearing system together form a magnetic liquid composite suspension bearing pair, which supports the gravity of the rotor assembly and the propeller, and bears the thrust of the propeller. The magnetic liquid composite suspension bearing pair is usually located on one side of the rotor, rather than at both ends of the rotor. This structure allows the bearing pair to be arranged on the same part, which is convenient for continuous processing during processing, ensures the coaxiality between the bearing pairs, and also improves processing efficiency and reduces manufacturing costs. When it is necessary to bear the thrust of the propeller reversing, a magnetic liquid composite suspension bearing system can also be arranged at the other end of the rotor, that is, there are magnetic liquid composite suspension bearing systems at both ends of the rotor.

[0047] In summary, the present invention improves propulsion efficiency: first, a permanent magnet brushless motor is adopted, and permanent magnets are used instead of coils. Compared with the traditional separately excited motor, the current loss is reduced, and the motor efficiency and power factor are improved; second, the inner circle of the motor rotor directly fixes the propeller, and the rotor directly drives the propeller to rotate, and no intermediate transmission link is required, thereby eliminating the loss caused by the intermediate transmission link; third, the magnetic fluid composite suspension bearing system supports the rotor assembly and the propeller, bears its weight and thrust, and keeps it in a suspended state during rotation, thereby reducing friction and friction power consumption. The above measures all improve the propulsion efficiency; the noise vibration of the present invention The rotor directly drives the propeller, which eliminates the vibration and noise caused by the meshing of the gearbox gears in the traditional propulsion type. Secondly, during the operation of the propeller, the bearing pair is a magnetic fluid suspension bearing system in a non-contact mode, and the friction noise and vibration are greatly reduced. In summary, the noise and vibration are reduced. The present invention has a simplified structure, a lighter weight, improved reliability, and less space in the cabin: the intermediate transmission components such as the coupling, gearbox, shaft system, sliding bearing and bearing seat, stern tube sealing system inherent in the traditional electric propulsion type are eliminated, the structure is simpler, the reliability is higher, and the weight is greatly reduced. In addition, since the motor is placed underwater, the cabin space is saved.

[0048] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0049] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention. At the same time, a person skilled in the art may make changes in the specific implementation methods and scope of application based on the ideas of the present application.

Claims

1. A ring-shaped electric propeller supported by a magnetic fluid composite suspension bearing, characterized in that: include: A housing, a rim-type motor, a magnetic fluid composite suspension bearing system and a propeller, wherein the rim-type motor comprises: a stator assembly, a rotor assembly and an end face flange, the stator assembly and the rotor assembly are arranged in the housing, and the two ends of the housing are respectively provided with the end face flanges; the magnetic fluid composite suspension bearing system is located on the end face flanges, and the magnetic fluid composite suspension bearing system comprises: a rotor end plate, a thrust plate, a dynamic thrust ring and a static thrust ring, the rotor end plate is connected to the rotor assembly and has a first gap channel between the end face flange, and the rotor end plate is provided with a thrust plate connected to the rotor assembly and has a first gap channel between the end face flange and the rotor end plate. The first water flow channel is connected to the first gap channel, the thrust plate is fixed to the end of the rotor end plate and has a second gap channel connected to the first gap channel between the thrust plate and the end face flange, and the thrust plate is provided with a second water flow channel connected to the second gap channel and the first water flow channel respectively, for water to flow through to form liquid suspension; the dynamic thrust ring is arranged on the inner wall of the thrust plate, and the static thrust ring is arranged on the outer wall of the end face flange at the position corresponding to the dynamic thrust ring, for generating magnetic repulsion to form magnetic suspension; the propeller is connected to the rotor assembly; The rotor end plate is also provided with a radial high-pressure water cavity, and the radial high-pressure water cavity is respectively connected with the first gap channel and the first water flow channel, and is used to generate radial high-pressure water flow; The thrust plate is also provided with an axial high-pressure water chamber and a water inlet. The axial high-pressure water chamber is respectively connected to the second gap channel and the second water flow channel for generating an axial high-pressure water flow. The water inlet is connected to the second water flow channel.

2. The annular electric thruster according to claim 1, characterized in that: The water inlet is connected with a high-pressure water pump.

3. The annular electric propulsion device according to claim 1, characterized in that: The magnetic fluid composite suspension bearing system further comprises: a friction reducing block, which is arranged on the outer wall of the end face flange.

4. The annular electric propulsion device according to claim 1, characterized in that: The stator assembly is fixed above the inner steps of the end face flanges at both ends, and the rotor assembly is located inside the stator assembly.

5. The annular electric propulsion device according to claim 1, characterized in that: The propeller is an integral propeller or a split propeller.

6. The annular electric propulsion device according to claim 1, characterized in that: The dynamic thrust ring and the static thrust ring are both permanent magnets or electromagnetic coils wrapped with corrosion-resistant and anti-corrosion coatings, with the same poles facing each other to generate magnetic repulsion.

7. The annular electric propulsion device according to claim 1, characterized in that: The rim-type motor is a rim-type permanent magnet brushless motor.

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