A ring-shaped electric propulsor driven by an axial flux motor

Abstract

The present invention relates to an annular electric propulsion device driven by an axial flux motor, comprising: a housing, an axial flux motor, a propeller and a bearing assembly. The annular electric propulsion device of the present invention uses an axial flux motor placed in water to directly drive the propeller to rotate, eliminating the intermediate transmission equipment, and the rotor and propeller assembly are supported by bearings placed in water and transmit the thrust to the motor and the hull; the intermediate transmission loss between the motor and the propeller is reduced, the efficiency is improved, the propulsion system structure is simplified, and the noise and vibration are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of ship turbine propulsion, and in particular relates to an annular electric propulsion device driven by an axial flux motor. Background Art

[0002] With the development of electric propulsion technology, electric propulsion systems are increasingly used in 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 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. This propulsion method has the following problems: complex structure, many parts, high failure rate, large space occupation, and heavy weight; low propulsion efficiency: the motor and propeller are transmitted through gears, shaft systems and other components, and the gear meshing produces energy loss. At the same time, the bearings are usually sliding bearings with large friction and high 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 order to reduce the intermediate transmission loss between the motor and the propeller, improve efficiency, simplify the propulsion system structure, reduce noise and vibration, etc., the present invention proposes an annular electric propeller driven by an axial flux motor, which uses an axial flux motor placed in the water to directly drive the propeller to rotate, eliminating the intermediate transmission equipment, and the rotor and propeller assembly are supported by bearings placed in the water and transmit thrust to the motor and the hull.

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

[0005] An annular electric propeller driven by an axial flux motor comprises: a housing, an axial flux motor, a propeller and a bearing assembly, wherein:

[0006] The axial flux motor comprises: an end face flange, a rotor assembly and a stator assembly, the end face flanges are respectively provided at both ends of the housing, the stator assembly is fixed on the end face flanges, the rotor assembly and the stator assembly are arranged in parallel, and the air gap magnetic field direction generated by the rotor assembly and the stator assembly is axial;

[0007] The propeller is connected to the rotor assembly via a blade tip flange, and the blade tip flange is located outside the end face flange;

[0008] The bearing assembly comprises: a thrust plate and a wear-resistant sleeve. The thrust plates are respectively fixed to both ends of the blade tip flange, and the thrust plates are located outside the end face flange. The wear-resistant sleeves are respectively arranged between the thrust plate and the end face flange and between the blade tip flange and the end face flange.

[0009] Furthermore, the rotor assembly includes: a permanent magnet and a support frame, the permanent magnet is embedded in the support frame, the support frame and the stator assembly are arranged in parallel, and one end of the support frame is connected to the blade tip flange.

[0010] Furthermore, a first axial wear-resistant sleeve is provided on the outer wall of the end face flange, and a second axial wear-resistant sleeve is provided on the inner wall of the thrust plate. The second axial wear-resistant sleeve and the first axial wear-resistant sleeve constitute a thrust bearing pair for bearing the forward and reverse thrust of the propeller.

[0011] Furthermore, a radial wear-resistant sleeve is provided on the outer wall of the end face flange, and the radial wear-resistant sleeve and the outer cylindrical surface of the blade tip flange constitute a radial bearing pair for bearing the weight of the rotor assembly and the propeller and the centrifugal force formed by eccentricity during rotation.

[0012] Furthermore, water grooves are provided on the surfaces of the radial bearing pair and the thrust bearing pair for accommodating mud and sand in the water and cooling the radial bearing pair and the thrust bearing pair by water flow.

[0013] Furthermore, the wear-resistant sleeves of the thrust bearing pair and the radial bearing pair are made of corrosion-resistant and wear-resistant metal or non-metallic materials, or polymer materials, or hard wear-resistant coatings.

[0014] Furthermore, the thrust bearing pair adopts paired permanent magnets or electromagnetic coils with the same polarities repelling each other to form a magnetic thrust bearing pair.

[0015] Furthermore, the propeller is an integral propeller or a split propeller.

[0016] Furthermore, protective covers are provided at both ends of the shell to protect the axial flux motor and the bearing assembly.

[0017] Furthermore, there are two stator assemblies, and there is one rotor assembly which is arranged between the two stator assemblies.

[0018] Furthermore, there are multiple stator assemblies and multiple rotor assemblies, and the rotor assemblies and the stator assemblies are alternately inserted into the shell.

[0019] The beneficial effects of the present invention include at least:

[0020] 1) The present invention adopts an axial flux permanent magnet brushless motor (disc motor) with a double-stator single-rotor structure. The axial forces on both sides of the rotor are balanced, the motor has high efficiency and a compact structure. Permanent magnets are used instead of coils, which reduces current loss and further improves motor efficiency and power factor compared to separately excited motors. Secondly, 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.

[0021] 2) The present invention adopts a double-stator single-rotor structure, and the magnetic fields on both sides of the rotor generate electromagnetic force to drive the rotor, output power at the same time, and have high power density, or integrate more stators and rotors to improve power density, or adopt a single stator and single rotor to reduce power density, simplify structure, and save costs;

[0022] 3) 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;

[0023] 4) Simplified structure, lighter weight, improved reliability, and less space occupied in the cabin: The present invention eliminates the intermediate transmission components inherent in traditional electric propulsion types, such as couplings, gear boxes, shaft systems, sliding bearings and bearing seats, stern tube and stern sealing systems, leaving only the motor, propeller and bearing group. The structure is simpler, the reliability is higher, and the weight is greatly reduced. In addition, since the motor is placed underwater, space in the cabin is saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the annular electric thruster of the present invention.

[0025] Figure 2 It is a schematic diagram of the structure of the integrated propeller of the present invention.

[0026] Figure 3 It is a schematic diagram of the split propeller structure of the present invention.

[0027] Figure 4 for Figure 1 Cross-sectional view along the line CC of the first embodiment.

[0028] Figure 5 for Figure 4 A partial enlarged view of .

[0029] Figure 6 for Figure 1 A cross-sectional view taken along the line CC of the second embodiment.

[0030] Figure 7 for Figure 6 A partial enlarged view of .

[0031] Figure 8 for Figure 1 A cross-sectional view along the line CC of the third embodiment.

[0032] Fig. 9 for Figure 8 A partial enlarged view of .

[0033] Among them, the shell 1, the propeller 2, the blade 201, the blade tip flange 202, the end face flange 3, the rotor assembly 4, the permanent magnet 401, the support frame 402, the stator assembly 5, the thrust plate 6, the first axial wear-resistant sleeve 7, the second axial wear-resistant sleeve 8, the radial wear-resistant sleeve 9, and the protective cover 10. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0035] Example 1: Figure 1 , 4 As shown in Figure 5, the annular electric thruster of this embodiment is a double-stator single-rotor assembly structure, mainly including: a housing, an axial flux motor, a propeller and a bearing assembly.

[0036] The axial flux motor of the present invention adopts an axial flux permanent magnet brushless motor (disc motor). The axial flux motor is different from an ordinary motor in that its air gap is planar, the direction of the air gap magnetic field is axial, the current-carrying conductor system is placed radially, and the stator and rotor are disc structures. The motor is composed of a stator assembly, a rotor assembly, a casing, and an end face flange. The left and right stator assemblies are respectively fixed on the left and right end face flanges of the motor, and a single rotor assembly is in the middle. The motor stator assembly is composed of an axial iron core and a coil, and can also be designed as a coreless structure. The stator assembly is integrally encapsulated with a multi-layer sealing insulation filling protective material to isolate it from water and play an insulating role. The rotor assembly is sandwiched between the two stator assemblies and is parallel to the stator assembly, rather than being radially concentric with the stator like an ordinary motor. The rotor assembly contains a permanent magnet and a support frame, the permanent magnet is embedded in the support frame, and the support frame is encapsulated with a sealing filling material to prevent water from entering the interior and corroding the permanent magnet. The casing is the propeller housing, and the left and right ends of the casing are connected to the end face flange and protective cover of the motor.

[0037] The inner diameter of the rotor is large enough to accommodate the propeller, which is fixed on the blade tip flange. The blade tip flange is connected to the inner diameter of the rotor support frame. 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 left and right stator components of the motor generate a rotating magnetic field after the three-phase power supply is connected. The permanent magnets in the middle rotor component generate electromagnetic force under the action of the rotating magnetic field. The rotor rotates and outputs torque, driving the propeller to rotate in the water to generate thrust to propel the ship.

[0038] The propeller can be a metal propeller or a composite propeller. The number of propeller blades is determined based on the calculation of hydrodynamic performance, and the number of blades can be 2, 3, 4, 5, 6 or more.

[0039] like Figure 2 As shown, the propeller can be an integral type, with the blade tips of each blade connected to a common blade tip flange as a whole, and then connected to the rotor support frame through the blade tip flange.

[0040] like Figure 3 As shown, the propeller blades can also be split, and each blade is fixed to the inner circle of the rotor support frame through a blade tip flange, supported and directly driven by the rotor. At the same time, since the propeller is made into a split type, it is also convenient for disassembly and replacement.

[0041] It can be understood that whether it is an integral propeller or a split propeller, they are all hubless propellers. Each blade is fixed to the rotor through a propeller flange and is directly driven by the rotor. The motor speed is the propeller speed. There is no need for a shaft system and hub for support and transmission, nor is there any need for intermediate transmission links such as transmission gears.

[0042] The bearing assembly of the present invention is a water-lubricated bearing, which bears the weight of the rotor assembly and the propeller, and also bears the forward and reverse thrust of the propeller. The bearing assembly is composed of left and right thrust plates, a thrust bearing pair, and a radial bearing pair.

[0043] Specifically: the left and right radial wear-resistant sleeves and the outer cylindrical surface of the blade tip flange form a radial bearing pair: the left radial wear-resistant sleeve and the left outer cylindrical surface of the propeller flange form a left radial bearing pair, and the right radial wear-resistant sleeve and the right outer cylindrical surface of the propeller flange form a right radial bearing pair. The left and right radial bearing pairs are concentric and jointly support the weight of the rotor assembly and the propeller, and withstand the centrifugal force caused by eccentricity during the rotation of the rotor assembly and the propeller.

[0044] The left and right thrust plates are connected to both ends of the blade tip flange. The second wear-resistant sleeve on the left thrust plate and the first wear-resistant sleeve installed on the left end face flange of the motor form a left thrust bearing pair. The second wear-resistant sleeve on the right thrust plate and the first wear-resistant sleeve installed on the right end face flange of the motor form a right thrust bearing pair, which respectively bear the forward and reverse thrust of the propeller.

[0045] The wear-resistant sleeves of the thrust bearing pair and the radial bearing pair are made of corrosion-resistant and wear-resistant metal or non-metal material, or polymer material, or hard wear-resistant coating, etc. The radial bearing pair and the thrust bearing pair may have water grooves on their surfaces to contain mud and sand in the water and cool the bearing pair through water flow.

[0046] The front and rear protective covers are installed at the front and rear ends of the motor housing to protect the motor and the rotating thrust plate. The front and rear protective covers can be made into arc shapes or streamlined shapes, which is beneficial to reduce resistance and improve hydrodynamic performance.

[0047] In many cases, due to the limited draft of the ship or the limited stern space, the radial dimensions of the propeller and thruster are limited, and the diameter of the propeller and thruster cannot be further increased. In order to increase the power under the condition of limited radial dimensions, the power can also be increased by increasing the number of stator assemblies and rotor assemblies. Under the condition of limited radial dimensions, the power and power density will increase if the number of motor stator assemblies and rotor assemblies integrated in the thruster increases; the power and power density will decrease if the number of motor stator assemblies and rotor assemblies integrated in the thruster decreases.

[0048] Example 2: When the power density requirement is not high, a single stator and single rotor type can be used to reduce the power and power density, such as Figure 6 and 7 As shown, the annular electric thruster of this embodiment is a single-stator single-rotor assembly structure. Different from Example 1, the number of stator assemblies is set to one group, and the rotor assembly is driven by a single stator assembly on one side only. By using a single stator and a single rotor, the power is reduced and the power density is reduced, but the structure is simple and the cost is low. It is suitable for thrusters with low power and low power density requirements.

[0049] Embodiment 3: When the power needs to be greater while the diameter remains unchanged, that is, the power density needs to be increased, this can be achieved by increasing the number of stator assemblies and rotor assemblies, that is, multiple stator assemblies drive multiple rotor assemblies at the same time, and multiple rotor assemblies drive one propeller at the same time. Figure 8 and 9 As shown, the annular electric propulsion device of this embodiment is a three-stator dual-rotor assembly structure. The difference from Embodiments 1 and 2 is that the three stator assemblies drive two rotor assemblies, and the two rotor assemblies drive one propeller at the same time.

[0050] The motor adopts a three-stator dual-rotor multi-disc structure. The front and rear stator assemblies are fixed on the front and rear end flanges of the motor respectively, and the middle stator assembly is embedded in the housing. There is a rotor assembly between every two stator assemblies. The front rotor assembly is between the front stator assembly and the middle stator assembly, and the rear rotor assembly is between the middle stator assembly and the rear stator assembly. The support frames of the two rotor assemblies are fastened together with the propeller blade tip flange to jointly drive the propeller to rotate, making the motor more powerful and improving the power density.

[0051] Similarly, more stator assemblies and rotor assemblies can be integrated on the propeller at the same time to drive a propeller at the same time, continuously improving the power and power density of the propeller, so that the propeller can produce greater thrust by increasing the power density and power while limiting the radial size.

[0052] Embodiment 4: Different from the above-mentioned embodiments 1-3, the thrust bearing pair can even adopt paired permanent magnets or electromagnetic coils with the same poles repelling each other to form a magnetic thrust bearing pair. The magnetic thrust formed by the repulsion can bear the weight of the rotor assembly and the propeller, and at the same time bear the forward and reverse thrust of the propeller. In addition, it can also reduce contact friction, reduce losses, and extend service life.

[0053] In summary, the present invention eliminates all transmission links between the motor and the propeller in the electric propulsion system. The motor directly drives the propeller and adopts an axial flux motor with a double-stator single-rotor structure or a multi-stator multi-rotor structure, which improves power density and efficiency and reduces operating noise. In addition, the elimination of the intermediate transmission link also reduces weight, improves reliability, reduces the occupied cabin space, and improves cabin space utilization. It is suitable for use on various electric ships.

[0054] 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.

[0055] 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. An annular electric propulsion device driven by an axial flux motor, characterized in that: include: housing, axial flux motor, propeller and bearing assembly, wherein: The axial flux motor comprises: an end face flange, a rotor assembly and a stator assembly, the end face flanges are respectively provided at both ends of the housing, the stator assembly is fixed on the end face flanges, the rotor assembly and the stator assembly are arranged in parallel, and the air gap magnetic field direction generated by the rotor assembly and the stator assembly is axial; The propeller is connected to the rotor assembly via a blade tip flange, and the blade tip flange is located outside the end face flange; The bearing assembly comprises: a thrust plate and a wear-resistant sleeve, the thrust plates are respectively fixed at both ends of the blade tip flange, and the thrust plate is located outside the end face flange, and the wear-resistant sleeve is respectively arranged between the thrust plate and the end face flange and between the blade tip flange and the end face flange; The rotor assembly comprises: a permanent magnet and a support frame, wherein the permanent magnet is embedded in the support frame, the support frame is arranged in parallel with the stator assembly, and one end of the support frame is connected to the blade tip flange; a first axial wear-resistant sleeve is arranged on the outer wall of the end face flange, and a second axial wear-resistant sleeve is arranged on the inner wall of the thrust plate, and the second axial wear-resistant sleeve and the first axial wear-resistant sleeve constitute a thrust bearing pair for bearing the forward and reverse thrust of the propeller; a radial wear-resistant sleeve is also arranged on the outer wall of the end face flange, and the radial wear-resistant sleeve and the outer cylindrical surface of the blade tip flange constitute a radial bearing pair for bearing the weight of the rotor assembly and the propeller and the centrifugal force formed by eccentricity during rotation; a water trough is arranged on the surface of the radial bearing pair and the thrust bearing pair for accommodating mud and sand in the water, and cooling the radial bearing pair and the thrust bearing pair by water flow; The thrust bearing pair adopts paired permanent magnets or electromagnetic coils with the same polarities repelling each other to form a magnetic thrust bearing pair; there are two stator assemblies, and there is one rotor assembly which is arranged between the two stator assemblies.

2. The annular electric propulsion device according to claim 1, characterized in that: The wear-resistant sleeves of the thrust bearing pair and the radial bearing pair are made of corrosion-resistant and wear-resistant metal or non-metal material, or polymer material, or hard wear-resistant coating.

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

4. The annular electric propulsion device according to claim 1, characterized in that: Both ends of the shell are provided with protective covers for protecting the axial flux motor and the bearing assembly.

5. The annular electric propulsion device according to any one of claims 1 to 4, characterized in that: There are multiple stator assemblies and multiple rotor assemblies, and the rotor assemblies and the stator assemblies are alternately inserted into the shell.

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