Marine journal sticking generator

Abstract

The marine journal sticking generator is characterized in that the magnetic flux density of the top of a stator is larger than that of the bottom of the stator, and upward unilateral magnetic pulling force is generated through an asymmetric magnetic field and is opposite to the gravity direction of a rotor and matched with the gravity direction of the rotor. The invention also provides an implementation mode of the asymmetric magnetic field. The implementation mode comprises eccentrically arranging the stator and the rotor and non-uniform coil windings. The rotor and a ship main engine shaft system are connected in an interference fit mode through an expansion sleeve and a flange, and lossless fastening of a ship tail shaft bearing is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of shaft-clamped generators, and in particular to a marine shaft-clamped generator, in particular to a generator with an asymmetric magnetic flux density setting. Background Art

[0002] A marine shaft-mounted generator (also known as a shaft-mounted generator) is a device that attaches the motor's rotor directly to the main engine's bearing (stern shaft), utilizing the propeller's rotational force to generate electricity. It is energy-efficient, highly efficient, compact, and low-maintenance. This design not only fully utilizes the main engine's rotational energy, reducing fuel consumption and improving energy efficiency, but also reduces the need for dedicated generators and extends their service life. Most ships currently under development and in service can be retrofitted with this type of generator.

[0003] However, in actual engineering applications, the permanent magnet rotor of a shaft-clamped generator is quite heavy, and its installation on a ship's main shaft creates a long-term load (there is a certain air gap between the stator and rotor, and the rotor is located on the ship's hull, not in direct contact with the main shaft). The rotating rotor can easily cause asymmetric fatigue on the bearing supports at both ends of the main shaft, thus reducing their lifespan, affecting the stable operation of the main shaft and the reliability of the shaft-clamped generator. Furthermore, since the rotor of a shaft-clamped generator is installed on the main engine shafting, drilling, pinning, or slotting of the original shafting is generally prohibited. Installation must be performed in a tightly closed, encircling manner. Otherwise, structural problems such as stress changes will occur in the main engine shafting. Ship main engines typically operate at speeds of up to or even exceeding 100 rpm. For a rotor weighing several tons, its moment of inertia is proportional to its mass. High-speed rotation can easily cause the rotor to slip relative to the main shaft. This can be particularly prone to bearing loosening when the generator is in operation for extended periods or subjected to external forces such as vibration and impact. This can affect generator operation, reduce power generation efficiency, and even lead to equipment failure, increasing repair costs and downtime.

[0004] Therefore, there is an urgent need to improve the reliability of shaft-clamped generators in marine environments. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art. On the one hand, it provides a shaft-enclosed generator, which uses the unilateral magnetic pull provided by the stator and rotor through the asymmetric field during the rotation process to cause the rotor to be subjected to a certain upward magnetic pull during the rotation, thereby reducing the load generated by the gravity of the rotor on the shaft it is engaged with; on the other hand, it improves the fastening force between the rotor and the shaft system of the shaft-enclosed generator, reduces and avoids the relative rotation or sliding between the rotor and the shaft system, thereby improving the reliability of the marine shaft-enclosed generator as a whole.

[0006] To achieve the above objectives, the present invention provides the following technical solutions: In a first aspect, the present invention provides a shaft-enclosed generator, comprising a rotor and a stator, wherein the rotor is fixedly mounted on a stern shaft bearing of a ship, and the stator is fixedly mounted on a hull, with an air gap between the two. Taking the axial dimension of the rotor or the stator as the boundary, the magnetic flux density I of the upper part of the rotor and the stator is greater than the magnetic flux density II of the lower part of the rotor and the stator, and the difference between the two magnetic flux densities is not less than 5% of the nominal magnetic flux density.

[0007] Furthermore, the rotor is fixedly mounted on a stern shaft bearing of a ship, the stator is fixedly mounted on a hull, the air gap between the top of the rotor and the stator is smaller than the air gap between the bottom of the rotor and the stator, and the variation of the air gap relative to the nominal value does not exceed 10% of the nominal air gap.

[0008] Furthermore, the asymmetric magnetic flux density is achieved by means of uneven coil windings of the stator, and the uneven coil windings are achieved by adjusting at least one of the number, area, wire diameter, core material, etc. of the coils.

[0009] In a second aspect, the present invention also provides a fastening structure for a rotor and a shaft it embraces, comprising a clamping sleeve sleeved on a stern shaft bearing, a flange, a rotor and a stator being sleeved on the outside of the clamping sleeve in sequence, a rotor pole being provided on the outer periphery of the rotor, a stator pole being provided on the outer periphery of the stator, and a lead being further provided on the stator pole.

[0010] Furthermore, the expansion sleeve is a conical cylinder structure, and a long groove is provided on the expansion sleeve from one end of the top corner to the bottom surface. The expansion sleeve is interference fit with the flange and is tightened to the flange by shrinking radially along the flange through the long groove.

[0011] Furthermore, the wall thickness of the expansion sleeve gradually increases from the top corner to the bottom surface, the cross section of the expansion sleeve along the busbar is wedge-shaped, and the expansion sleeve is inserted into the flange.

[0012] Furthermore, the expansion sleeve is divided into at least two separate parts along the busbar.

[0013] Furthermore, an assembly ring is radially extended from the outer periphery of one end of the bottom surface of the expansion sleeve, and an assembly hole is provided on the assembly ring along the axial direction of the expansion sleeve. A connecting hole is provided on the end surface of the flange corresponding to the assembly hole, and a thread is provided inside the connecting hole. The connection between the expansion sleeve and the flange is achieved by bolts passing through the assembly hole and the connecting hole in sequence.

[0014] Furthermore, a locking hole is provided at one end of the long groove located on the bottom surface of the cone.

[0015] Furthermore, the expansion sleeves are symmetrically arranged on two end surfaces of the flange.

[0016] The advantages and beneficial effects of the present invention are: The magnetic flux density at the upper part of the stator of the generator shown in the present invention is greater than that at the lower part. An asymmetric magnetic field is used to generate an upward unilateral magnetic pull, which is opposite to the direction of the rotor gravity and matches the magnitude, thereby achieving rotor suspension, reducing mechanical contact of the bearings, lowering friction losses, and extending bearing life.

[0017] The fastening structure between the rotor and the ship's stern shaft shown in the present invention adopts a split-structure expansion sleeve that is inserted into the flange through interference fit, and utilizes the long groove opened in the expansion sleeve to provide the margin for radial contraction of the expansion sleeve, thereby greatly improving the fastening force of the rotor on the ship's stern shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a structural schematic diagram of the expansion sleeve of the present invention; Figure 3 Schematic diagram of the cross-sectional structure of the expansion sleeve of the present invention; Figure 4 It is a structural schematic diagram of the assembly ring of the present invention; Figure 5 is a scatter plot of unilateral magnetic pull and eccentricity during the installation process of the present invention; Figure 6 is a scatter plot of unilateral magnetic pull and eccentricity in the operating state of the present invention; Figure 7 This is a three-phase voltage waveform diagram when the stator-rotor of the present invention is not eccentric; Figure 8 This is a three-phase voltage waveform diagram when the stator-rotor eccentric air gap is 10%; Figure 9 This is a graph showing the measured data of the shaft runout of the rotor at the stern of the ship according to the present invention; In the picture: 1-stern shaft bearing, 2-rotor, 3-stator, 4-expansion sleeve, 5-flange, 6-long slot, 7-split component, 8-assembly ring, 9-assembly hole, 10-connection hole, 11-locking hole, 12-combination hole. DETAILED DESCRIPTION

[0019] The air gap between the rotor and stator of a shaft-clamped generator is a critical channel for magnetic field transmission. A uniform air gap ensures symmetrical magnetic field distribution, preventing unilateral magnetic pull from causing additional vibration and mechanical stress, which could damage bearings or coil windings. Furthermore, an uneven air gap increases local magnetic resistance, increasing hysteresis and eddy current losses, and reducing energy conversion efficiency. Furthermore, eccentricity can also place additional radial loads on the bearings, accelerating wear and even leading to bearing failure. Therefore, traditional rotor and stator configurations are strictly concentric.

[0020] Unilateral magnetic pull (UMP) is the net radial magnetic force generated by an asymmetric magnetic field distribution in a motor or electromagnetic device (e.g., an eccentric air gap or unequal pole spacing). Its magnitude is directly related to the magnetic flux density distribution. When the rotor and stator axes are misaligned (eccentric), the air gap (air gap) is narrower on one side and wider on the other. In areas with narrow air gaps, magnetic reluctance is lower, allowing magnetic flux lines to pass more easily, increasing magnetic flux density (B). In areas with wide air gaps, reluctance is higher, reducing magnetic flux density.

[0021] According to the Maxwell stress tensor, when the tangential component is neglected, the magnetic pull per unit area is .

[0022] The total unilateral magnetic pull F is obtained by integrating the difference in magnetic flux density on both sides of the air gap: .

[0023] Where B max , B min are the magnetic flux densities (T) at the maximum and minimum air gaps, respectively, and μ0 is the vacuum permeability (4π*10 - 7 H / m), A is the air gap area (m 2 ).

[0024] According to the magnetic formula F∝B 2 , the magnetic pull generated by areas of high flux density is significantly stronger than that generated by areas of low flux density. Under static or low-speed conditions, the narrower air gap creates a high-intensity magnetic field, generating a greater attractive force; the wider air gap creates a weaker magnetic field, resulting in less pull. This asymmetry results in a net magnetic pull on the rotor directed toward the narrower air gap.

[0025] Traditional shaft-clamped generators require strict concentricity between the rotor and stator to prevent bearing wear and vibration caused by unilateral magnetic pull. This invention overcomes this technical bias by proactively utilizing asymmetric magnetic flux density. The flux density at the upper part of the stator is pre-set to be greater than that at the lower part, generating an upward unilateral magnetic pull that is opposite in direction and matched in magnitude to the rotor's gravity, reducing the load on the ship's stern shaft from the rotor.

[0026] The following embodiments are further described in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0027] like Figure 1-3As shown, the present invention provides a marine shaft-enclosed generator, which includes a rotor 2 and a stator 3 sleeved on a stern shaft bearing 1 of a ship. There is an air gap between the rotor 2 and the stator 3. With the transverse plane where the axis of the rotor or the stator is located as the boundary, the magnetic flux density I of the upper part of the rotor 2 and the stator 3 is greater than the magnetic flux density II of the lower part of the rotor and the stator, and the change in magnetic flux density between the upper part and the lower part is not less than 5% of the nominal magnetic flux density.

[0028] As a preferred embodiment, the asymmetric magnetic field distribution, especially the vertically asymmetric magnetic flux density, is implemented in the following ways, but not limited to: a. The stator is eccentrically positioned downward outside the rotor to create an air gap that is thinner at the top and wider at the bottom; b. By reducing at least one of the number of turns, cross-sectional area and wire diameter of the stator coil winding from top to bottom; At this point, it is necessary to consider the significant differences in power generation quality within the stator coil windings, including but not limited to voltage waveform, phase, efficiency characteristics, harmonic content, and dynamic response. It is important to note that changes in the number of coil turns or cross-sectional area only affect the amplitude distribution of the magnetomotive force (MMF) and do not alter the magnitude. This can be addressed by connecting a separate amplitude modulation circuit. Different core materials may cause differences in the perceived equivalent magnitude due to magnetic field distortion. This can be optimized through magnetic circuit compensation based on actual needs. Alternatively, a separate energy storage device can be connected to output a stable current through a voltage regulator, transformer, or other device.

[0029] like Figure 1-Figure 3 As shown, the present invention also provides a mechanical connection method for the rotor of the shaft-enclosed generator and the stern shaft of a ship, which includes a clamping sleeve 4 sleeved on the stern shaft bearing 1, and a flange 5, a rotor 2 and a stator 3 are sequentially sleeved on the outside of the clamping sleeve 4. The outer peripheries of the rotor 2 and the stator 3 are respectively provided with rotor poles and stator poles, and the stator poles are also provided with leads for outputting electricity.

[0030] In order to make it easier for the expansion sleeve 4 to be inserted into the through hole on the end face of the flange 5, the expansion sleeve 4 can be manufactured into a conical cylinder structure, and one end of the top angle of the cone can be provided with a groove to reduce the wall thickness, so that the end face of the expansion sleeve 4 can achieve a clearance fit between the flange 5 and the stern shaft 1 of the ship, so that the end face part can be easily inserted into the flange 5.

[0031] In order to increase the tightening force of the expansion sleeve 4, the expansion sleeve 4 can generate radial pressure between the flange 5 and the ship's stern shaft 1, thereby increasing the pressure according to the friction formula, thereby further increasing the friction between the expansion sleeve 4 and its adjacent two parts, and improving the clamping effect between the rotor and the ship's stern shaft. The cross-section of the expansion sleeve 4 along the generatrix is wedge-shaped, and the wall thickness of the expansion sleeve 4 gradually increases from thin to thick from the top angle to the bottom surface. When the expansion sleeve 4 is gradually inserted into the flange 5, the wedge-shaped structure can gradually increase the tightening force.

[0032] To ensure efficient and stable connection of the expansion sleeve 4 to the end face of the flange 5, minimizing or preventing tilting that could reduce installation stability, a mounting ring 8 is radially extended from one end of the bottom surface of the expansion sleeve 4. The mounting ring 8 is provided with multiple mounting holes 9 along the axial direction of the expansion sleeve 4. Connecting holes 10 are provided corresponding to the connecting end faces of the flange 5 and the expansion sleeve 4. The interiors of the connecting holes 10 are threaded. The expansion sleeve 4 and flange 5 are connected by bolts that pass through the mounting holes 9 and 10 in sequence. As a preferred embodiment, the bolts can be tightened diagonally one by one, with the mounting rings gradually approaching and being inserted into the flange 5 using the nuts of the bolts. This diagonal tightening maintains the stable installation of the expansion sleeve 4.

[0033] In order to make it easier for the expansion sleeve to be installed on the ship's stern shaft 1, it is not necessary to disassemble the ship's stern shaft 1 into multiple sections and then slide the expansion sleeve 4 along the end face of the ship's stern shaft 1. The expansion sleeve 4 can be divided into at least two separate parts along the busbar, and the two separate parts are buckled together on the ship's stern shaft 1, so that the ship's stern shaft 1 does not need to be disassembled. Although the separate parts do not need to be specially combined together, considering that the expansion sleeve has a certain weight, when multiple people clamp or hoist it, in order to maintain relative stability between the separate parts and the ship's stern shaft 1 and to insert at least two separate parts into the interior of the flange 5 together, it is avoided that during the insertion process one by one, the long slot 6 of the separate part inserted first does not shrink, resulting in the separate part entering the flange 5 later being limited. The solutions provided by the present invention include, such as Figure 4 As shown, a combination hole 12 can be provided on the assembly ring 8 of the expansion sleeve 4 along a chord length defense line. After the two separate components are respectively fastened to the ship stern shaft 1, the combination hole is connected by bolts to form a whole.

[0034] In order to avoid unnecessary weight brought by the deadweight of the bolts of each part, so as to avoid causing unnecessary load to the stern shaft 1 of the ship, the bolts including the assembly holes 9 and the combination holes 12 can be removed after the assembly or combination is completed.

[0035] In order to prevent the long groove 6 from being excessively deformed due to deformation, shrinkage or stress concentration during production and processing, or during the assembly of the expansion sleeve 4 on the flange 5, thereby causing the part between the two long grooves 6 of the expansion sleeve 4 to break, the embodiment provided by the present invention includes providing a locking hole 11 at one end of the long groove 6 located on the bottom surface of the cone.

[0036] In order to ensure the stable connection of the rotor 2 on the flange 5, and to reduce the need for a single expansion sleeve 4 to pass through the flange 5 to ensure that the gap between the expansion sleeve 4 and the flange 5 is fully filled, and at the same time prevent the problem of clearance fit between one end of the wedge-shaped expansion sleeve and the flange 5, the technical solution provided by the present invention includes symmetrically arranging two expansion sleeves 4 on the two end surfaces of the flange 5.

[0037] The mechanical connection structure between the above-mentioned shaft-clamped generator rotor and the ship's stern shaft not only avoids the damage to the shaft system caused by traditional key connection, but also provides sufficient pressure / static friction to prevent insufficient clamping force between the rotor and the main engine bearing, thereby avoiding the slippage problem between the rotor and the ship's stern shaft under long-term service conditions.

[0038] Example 1 This embodiment uses a stator that is eccentrically arranged with the rotor to achieve an asymmetric magnetic field. When the stator is installed, one end is offset upward by a distance S. Figure 5-Figure 6 The figure shows the corresponding relationship between the unilateral magnetic pull and the eccentricity of the stator during installation.

[0039] As a further illustration of this embodiment and to show the effect of an eccentric stator-rotor arrangement in actual engineering, see Figure 7-Figure 8 Influenced by the tolerance and processing accuracy of related components, the stator-rotor inevitably has a certain eccentricity during actual operation. It is not difficult to understand that the acceptable eccentricity of the stator-rotor is usually controlled within 10% of the air gap value. For the shaft power generation system, the voltage-current imbalance is within the control range of the inverter.

[0040] Through finite element analysis, Figure 7-Figure 8 The simulation demonstrates a comparison of voltage imbalance values for a 1000kW stator-rotor system before and after a 10% air gap eccentricity. Electrically, under rated operating conditions, the three-phase voltage imbalance is 0.76% before and after a 10% air gap eccentricity. This indicates that a 10% air gap eccentricity has minimal impact on power quality, comparable to or even less than typical power fluctuations, making the actual impact negligible. Figure 9 The graph shows the shaft runout measurement data at the stern. From a mechanical perspective, the reduction in air gap caused by stator-rotor eccentricity poses a risk of motion interference between the stator and rotor. Figure 9 The measured reference air gap is 11.63mm. During the main engine operating time (in seconds), the maximum air gap fluctuation is 12.19mm, with a fluctuation range of 0.56mm. Considering that the actual stator-rotor air gap is typically at least 4mm, the fluctuation range is smaller than the air gap width, indicating that the risk of stator-rotor friction is within a manageable range.

[0041] As a preferred embodiment, the stator is fixedly mounted within the housing. When the housing is lowered, the stator is eccentrically fixed downwardly along the rotor. This connection can be secured via a base between the housing and the cabin. The base is provided with a sinking margin. A laminated gasket, preferably a stack of multiple sheets of copper, iron, or stainless steel, approximately 0.5-1 mm thick, can be placed between the housing and the base to adjust the eccentricity between the stator and the rotor. Methods for securing this laminated structure between the base and the housing include, but are not limited to, rigid connections such as bolts, rivets, and welding.

[0042] Example 2 This embodiment utilizes stator coil windings to achieve an asymmetric magnetic field. During stator manufacturing, the stator's top coils are densely arranged, with the number of windings per unit area 1.2-1.5 times that of the bottom coils. Furthermore, the cross-sectional area of the top coil conductors is 10%-15% larger than that of the bottom coils. By increasing the number of turns and conductive area of the top coils, the magnetic field strength in this area is enhanced. The bottom coils are sparsely arranged, with a reduced cross-sectional area, to reduce the magnetic flux density in this area. The clamping structure between the top coils and the main engine shaft is the same as in the previous embodiment.

[0043] As a further illustration, in a 1000kW prototype test, the rotor suspension height of the generator with an asymmetric coil design was stable at 0.5mm±0.1mm at rated speed, and the three-phase voltage imbalance was measured to be 0.82%, comparable to the eccentric structure performance of Example 1, verifying the feasibility of this solution. Finite element simulation analysis showed that the magnetic field strength at the top of the stator reached 1.8T and at the bottom was 1.2T, resulting in a magnetic flux density difference of approximately 50% between the top and bottom. According to the magnetic force formula, the unilateral magnetic pull generated at the top is approximately 2.25 times that at the bottom, which at least offsets part of the rotor's gravity and reduces the load on the shaft system it holds.

[0044] As a preferred implementation, the stator coils are asymmetrically distributed through a segmented winding process. After assembly, Hall sensors are used to monitor magnetic field uniformity. If the magnetic pull force falls short of the preset value, calibration can be performed by fine-tuning the additional compensation winding on the top coil (reserving 5% redundant turns) to ensure that the single-sided magnetic pull force precisely matches the rotor's weight.

[0045] As a preferred embodiment, the stator structure should incorporate the following adaptive improvements, including but not limited to: The stator core adopts a layered design, with more slots reserved in the top area to accommodate densely packed coils. Each layer of windings is separated by insulating partitions to mitigate the risk of insulation breakdown due to the increased number of turns. The top slot depth is increased by 15%-20% compared to the bottom slot depth, ensuring ample winding space and a concentrated magnetic field.

[0046] As a preferred embodiment, the manufacturing process of the asymmetric winding can adopt segmented winding of the stator winding: the top area is wound with high precision and density (such as turn spacing ≤ 0.5mm) by an automated winding machine, and the bottom area is wound sparsely (such as turn spacing ≥ 1.2mm).

[0047] Example 3 This embodiment uses different core materials for the upper and lower stator coil windings to achieve an asymmetric magnetic field. The upper stator core is made of high-permeability silicon steel sheets (B30AHV1300) with a saturation flux density of 2.0T; the lower stator core is made of amorphous alloy (1K101) with a saturation flux density of 1.8T. The upper winding adopts a centralized 6-slot structure, while the lower adopts a distributed 12-slot structure, with winding spans set at 120° and 60° electrical angle, respectively. The difference in hysteresis loops between the silicon steel sheets and the amorphous alloy reduces the magnetic resistance of the upper magnetic circuit by 15%-20%, allowing magnetic flux to preferentially flow through the upper path, generating a longitudinal magnetic field gradient. At a rated speed of 300 rpm, the upper magnetic flux density reaches 1.45T and the lower 1.32T, a gradient difference of 9.4%.

[0048] As a preferred implementation scheme, the distributed winding is connected in parallel with a neodymium iron boron permanent magnet array (N52 grade), and compensating magnetic potential is injected into the amorphous alloy segment to control the equivalent pole number deviation within ±0.2 levels, thereby avoiding the current quality difference between the upper and lower parts of the stator caused by the number of poles problem.

[0049] As a preferred embodiment, the coil windings on the upper part of the stator are connected to an LC filter (L=5mH, C=220μF), and the coil windings on the lower part of the stator are connected to an active harmonic compensator, which reduces the THD from 7.8% to 3.2%.

[0050] As a preferred embodiment, a three-level converter is used to grade the power quality of the upper and lower parts of the stator.

[0051] Example 4 This embodiment aims to achieve an asymmetric magnetic field arrangement for the magnetic field of a single coil winding generated by armature reaction tempering under different current loads of distributed coil windings. The stator is provided with two layers of independent windings: the upper layer is a 4-pole star connection (wire diameter 1.6mm), and the lower layer is a 6-pole triangle connection (wire diameter 2.5mm). 80% of the rated current is injected into the upper layer (power factor 0.8 lagging), and the lower layer is overloaded to 120% of the rated current (power factor 0.7 leading). Through dq-axis decoupling control, the upper layer of the winding focuses on magnetic flux control (d-axis current accounts for 70%), and the lower layer focuses on the torque component (q-axis current accounts for 85%). Finite element analysis shows that the armature reaction magnetic field causes the main magnetic field to move up by 12°, the upper magnetic density is increased to 1.5T, and the lower part is reduced to 1.38T, with a gradient difference of 8% As a preferred implementation scheme, a third harmonic injection technique is used to connect a third harmonic trap circuit (Q value > 50) in parallel to the lower winding, while a fifth harmonic cancellation algorithm is implemented in the upper layer.

[0052] As a preferred implementation scheme, the stator is integrated with a Hall array (16-point circular distribution) to monitor the magnetic field distribution in real time. Each stator coil is connected to a load-type control circuit. The Hall array is calculated by DSP (TMS320F28335) and the optimal compensation current of the control circuit is used to achieve stable output of the power generation quality of the shaft-holding generator.

[0053] As a preferred implementation, each stator coil winding is connected to a supercapacitor bank (2.7V / 3000F×120 pieces) for dynamic energy storage. The supercapacitor bank is also connected in parallel with a SiC MOSFET bidirectional converter to achieve ±5% voltage fluctuation suppression.

[0054] The working principle of the present invention is that, on the one hand, an asymmetric magnetic field is actively set, in particular an asymmetric magnetic flux density, so that the rotor mounted on the stern shaft of the ship obtains an upward unilateral magnetic pull. The unilateral magnetic pull can be used to balance the gravity acting on the rotor, specifically taking on the directional component of the rotor's gravity, thereby enabling the heavier rotor to reduce the load it causes on the stern shaft of the ship. The present invention is particularly suitable for working conditions such as high and / or limited stern shaft loads on ships in service.

[0055] Secondly, the present invention adopts a clamping sleeve with a long groove arranged axially to achieve interference fit with the flange through radial reduction of the long groove, thereby improving the clamping force between the rotor and the stern shaft of the ship.

[0056] The generator shown in this invention is particularly suitable for demanding operating conditions, such as those encountered on ships. Its magnetic levitation significantly reduces main engine bearing wear, while its expansion sleeve ensures long-term operational stability. The entire system significantly extends equipment life while maintaining power generation efficiency. It also addresses the issue of insufficient clamping force and main engine bearing deformation caused by heavy loads in conventional shaft-clamped generators.

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A marine shaft-clamped generator, wherein the rotor is fixedly mounted on the ship's stern shaft bearing, the stator is fixedly mounted on the hull, and an air gap exists between the rotor and the stator, characterized in that: The air gap between the top of the rotor and the stator is smaller than the air gap between the bottom of the rotor and the stator, and the change of the air gap relative to the nominal value is greater than or equal to 1% of the nominal air gap and does not exceed 10% of the nominal air gap.

2. The marine shaft-clamped generator according to claim 1, characterized in that: The rotor is fixedly mounted on a stern shaft bearing of a ship, and the stator is fixedly mounted on a hull, with an air gap between the two. The air gap between the top of the rotor and the stator is smaller than the air gap between the bottom of the rotor and the stator, and the variation of the air gap relative to the nominal value does not exceed 10% of the nominal air gap.

3. The fastening structure of the shaft-enclosed generator according to any one of claim 2, characterized in that: The invention comprises a tightening sleeve (4) sleeved on a stern shaft bearing (1), wherein a flange (5), a rotor (2) and a stator (3) are sleeved on the outer side of the tightening sleeve (4) in sequence, a rotor magnetic pole is arranged on the outer periphery of the rotor (2), a stator magnetic pole is arranged on the outer periphery of the stator, and a lead wire is also arranged on the stator magnetic pole.

4. The fastening structure of the shaft-holding generator according to claim 3, characterized in that: The expansion sleeve (4) is a conical cylinder structure. The expansion sleeve (4) is provided with a long groove (9) from one end of the top corner to the bottom surface. The expansion sleeve (4) is interference-fitted with the flange (5) and is tightened to the flange (5) by contracting radially along the flange (5) through the long groove (6).

5. The fastening structure of the shaft-holding generator according to claim 3, characterized in that: The wall thickness of the expansion sleeve (4) increases from thin to thick from the top corner to the bottom surface. The cross section of the expansion sleeve (4) along the busbar is wedge-shaped. The expansion sleeve is inserted into the flange (5) through the wedge-shaped structure (4).

6. The fastening structure of the shaft-holding generator according to claim 3, characterized in that: The expansion sleeve (4) is divided into at least two separate parts (7) along the busbar.

7. The fastening structure of the shaft-holding generator according to claim 3, characterized in that: An assembly ring (8) is radially extended from the outer periphery of one end of the bottom surface of the expansion sleeve (4), and an assembly hole (9) is axially arranged on the assembly ring (8) of the expansion sleeve (4). A connecting hole (10) is correspondingly arranged on the end surface of the flange (5) and the assembly hole (9). A thread is arranged inside the connecting hole (10), and the connection between the expansion sleeve (4) and the flange (5) is achieved by bolts passing through the assembly hole (9) and the connecting hole (10) in sequence.

8. The fastening structure of the shaft-holding generator according to claim 3, characterized in that: A locking hole (11) is provided at one end of the long groove (6) located on the bottom surface of the cone.

9. The fastening structure of the shaft-clamping generator according to claim 2, characterized in that: The expansion sleeves (4) are symmetrically arranged on the two end faces of the flange (5).

10. The marine shaft-engaged generator according to claim 5, characterized in that: A split assembly hole (12) is provided at the split assembly portion of the split component assembly ring (8) of the expansion sleeve (4) along the chord length direction.

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