A flat compact generator

Abstract

The application provides a flat compact generator, and belongs to the technical field of generators, which solves the problems of large volume, complex structure and low heat dissipation efficiency of the existing generator. The generator comprises a front end cover, a casing, a rear end cover and a rear cover cover. The outer part of the front end cover is provided with an air outlet mesh cover. The outer part of the upper end of the casing is provided with a wiring board and a wire outlet box. The inner side of the wire outlet box is provided with an automatic voltage regulator. The inner part of the casing is fixedly provided with a main stator. The front end of the rear end cover is provided with an excitation stator. The rear cover cover is arranged at the rear end of the rear end cover. The inner part of the rear end cover is provided with a bearing. The inner ring of the bearing is fixedly provided with a main shaft. A plurality of closely arranged disc couplings and a locking plate are sequentially arranged on the front end surface of the main shaft from back to front by locking screws. A heat dissipation fan blade, a main rotor and an excitation rotor are sequentially arranged on the main shaft from front to back. The rear side end surface of the excitation rotor is provided with a rectifier bridge. The application realizes flat and compact design, and optimizes the smoothness of the internal cooling air duct to improve the heat dissipation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of generator technology, and relates to a generator, particularly a flat and compact generator. Background Technology

[0002] Traditional brushless generators, to ensure sufficient power output and reliable heat dissipation, typically have a long axial length and large size, making them difficult to meet the compact installation space requirements of modern equipment (such as vehicle-mounted, marine, or specialized portable devices). Simply compressing the internal space to reduce size leads to a sharp decline in heat dissipation performance. Existing generator cooling duct designs generally suffer from the following problems:

[0003] The winding airflow path easily generates eddies: In traditional generators, the diameters of the main stator and rotor and the excitation stator and rotor are relatively close. To avoid interference and ensure heat dissipation, a large axial gap must be reserved between them. This causes the cooling airflow to bend before entering the air gap between the main stator and rotor after entering from below the casing. This easily creates eddies in the cavity between the excitation and main stator and rotor, hindering the smooth flow of airflow and resulting in low heat dissipation efficiency.

[0004] Low axial space utilization: The cooling fan blades and stator windings are arranged side by side in the axial direction, and the main stator and rotor and the excitation stator and rotor have a large axial distance reserved, which occupies valuable axial length.

[0005] Complex structure and high air resistance: In order to enhance heat dissipation, it is often necessary to open additional air inlets on the casing and adopt traditional structures with high air resistance (such as square or fan-shaped ribs), which increases the complexity of the structure and airflow resistance.

[0006] Therefore, there is an urgent need in this field for a flat, compact generator that can significantly reduce axial dimensions while ensuring efficient heat dissipation. Summary of the Invention

[0007] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a flat and compact generator. The technical problem this invention aims to solve is: how to achieve a flat and compact design for the generator and optimize the smoothness of its internal cooling airflow.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A flat, compact generator includes a front cover, a housing, a rear cover, and a rear cover, connected sequentially from front to back. The front cover has an external air vent grille. The upper part of the housing has a terminal block and a terminal box. The terminal block is located inside the terminal box, and an automatic voltage regulator is located inside the terminal box. A main stator is fixed inside the housing. An excitation stator is located at the front end of the rear cover, inside the housing and behind the main stator. The rear cover is located at the rear end of the rear cover, and a bearing is located inside the rear cover. The inner ring has a fixed main shaft. The front end face of the main shaft has several closely fitting disc couplings and a locking plate arranged sequentially from back to front via locking screws. The main shaft has a cooling fan, a main rotor, and an excitation rotor arranged sequentially from front to back. The cooling fan is located inside the front end cover. The main rotor is located inside the main stator and is electromagnetically coupled to the main stator. The excitation rotor is located inside the excitation stator and is electromagnetically coupled to the excitation stator. The rear end face of the excitation rotor has a rectifier bridge. The terminal block is electrically connected to the main stator and the excitation stator.

[0010] The working principle of this invention is as follows: The excitation stator and excitation rotor assembly are nested in the radial space behind the main rotor, allowing the axial distance between the main and excitation parts to be compressed to a minimum; a wide and unobstructed annular axial airflow channel is formed between the main rotor and the excitation rotor; after the cooling air is filtered by the rear cover, the clean air enters the housing from the rear cover; most of the cooling airflow flows straight forward through the annular space between the excitation rotor and the excitation stator, flushing the air gap between the main stator and the main rotor. This straight path effectively avoids the generation of eddies; part of the airflow flows forward along the annular gap between the inner wall of the housing and the outer circle of the main stator. The housing assists in the airflow, directly guiding the cold air to the main stator and enhancing the cooling of the main stator; all the heated airflow is driven by the cooling fan blades to converge at the front cover, reducing the air outlet resistance. The hot air is finally smoothly discharged outside the machine through the air outlet screen and blown out obliquely forward, avoiding the hot air flowing back to the air inlet of the generator and affecting the cooling efficiency;

[0011] Main power generation circuit: The prime mover drives the main shaft to rotate through the disc coupling, which drives the cooling fan, main rotor and excitation rotor to rotate together. After DC current is applied to the windings on the main rotor, a rotating magnetic field is generated. This magnetic field cuts the three-phase armature windings of the main stator, thereby inducing a three-phase AC electromotive force in the main stator, and outputting electrical energy through the terminal block.

[0012] Excitation power supply: The automatic voltage regulator outputs an adjustable DC current to the excitation winding of the stationary excitation stator based on the feedback signal of the generator output voltage.

[0013] Rotary rectification: The static magnetic field generated by the excitation stator is cut by the armature winding on the coaxially rotating excitation rotor, inducing three-phase alternating current in the excitation rotor. This alternating current is immediately converted into direct current by the rotary rectifier bridge installed at the rear end of the excitation rotor.

[0014] Magnetic field establishment: The rectified DC power is directly supplied to the excitation winding of the main rotor through the connection of the main shaft or a special wire, thereby establishing the main rotating magnetic field and completing the excitation energy transfer of the brushless system.

[0015] Throughout the process, the automatic voltage regulator continuously monitors the generator output voltage. When load changes cause voltage fluctuations, the automatic voltage regulator quickly adjusts the magnitude of the DC current supplied to the excitation stator, thereby changing the excitation intensity and ultimately stabilizing the main generator's output voltage.

[0016] The housing includes a housing body. Two symmetrically arranged mounting bases are fixed to the lower end of the housing body. Two symmetrically arranged clearance holes are opened at the upper end of the housing body. A base and four symmetrically arranged mounting plates are fixed to the upper end of the housing body. The base is located between the two clearance holes. A wiring board is detachably mounted on the upper end of the base with screws. The corresponding two mounting plates are located on the front and rear sides of the clearance holes at their respective positions. A front flange is fixed to the front side of the housing body, and a rear flange is fixed to the rear side of the housing body. Several circumferentially distributed stator fixing ribs are provided inside the housing body. The interior of the stator fixing ribs is hollow, forming air guide channels. Several exhaust holes are opened on each stator fixing rib. The length of the stator fixing ribs is less than the length of the housing body.

[0017] Using the above structure, the main casing forms the main chamber of the generator, used to house and fix core electromagnetic components such as the main stator and main rotor, serving as the mechanical foundation of the generator. Two mounting bases at the lower end provide fulcrums for connecting the entire generator to the foundation or mobile platform, while the upper base is used to mount the terminal block, and four mounting plates provide the mounting interface for the outlet box. The front flange of the casing at the front end and the rear flange at the rear end are used to achieve a sealed and robust connection with the front and rear covers, respectively, forming a completely enclosed motor cavity. Two clearance holes at the upper end provide channels for the lead cables of the main stator and excitation stator to reach the outlet box. Several circumferentially distributed stator fixing ribs are designed with a hollow structure inside, serving as air guide channels. When cooling airflow from the rear cover... After entering the main body of the motor housing, some airflow is guided into the air guide channel, except for the gap between the main air duct and the inner wall of the main body. The length of the stator fixing rib is less than the length of the main body of the motor housing, and its ends are open to facilitate air inlet and outlet. A negative pressure is formed inside the air guide channel. Under the action of air pressure difference, the hot air on the outer surface of the back of the main stator is drawn into the air guide channel through several exhaust holes and discharged from the main body of the motor housing, improving the heat dissipation efficiency of the main stator and making the temperature field distribution inside the motor more uniform. The stator fixing rib and the main air duct work together in parallel to form a three-dimensional cooling network with clear primary and secondary components and comprehensive coverage. All the airflow entering the main body of the motor housing is finally drawn together by the negative pressure generated by the cooling fan blades and discharged to the perimeter of the front cover.

[0018] The main stator includes a hollow ventilation frame, which is open at both ends. The hollow ventilation frame is engaged with several stator fixing ribs. The main stator body is located inside the hollow ventilation frame. Several sets of circumferentially distributed and penetrating ventilation holes are opened on the hollow ventilation frame. Each set of ventilation holes corresponds to the position of the stator fixing ribs, and the ventilation holes are connected to the exhaust holes at the corresponding positions.

[0019] With the above structure, the main stator body is the core armature of the generator, made of laminated silicon steel sheets and embedded with three-phase windings. During operation, it generates a large amount of heat due to iron and copper losses, making it the main heat source. The hollow ventilation frame, open at both ends, accommodates and supports the main stator body, engaging between several stator fixing ribs, serving a radial positioning and fixing function. It also acts as a structural interface and airflow distributor connecting the air duct to the main stator body and the generator housing, forming a continuous cooling path. Several sets of evenly distributed circumferential ventilation holes are correspondingly opened on the hollow ventilation frame and the main stator body. Each set of ventilation holes is aligned and connected to a corresponding stator fixing rib and its exhaust hole on the generator housing body. After the cooling airflow enters the generator housing body from the rear end, a portion is guided by the stator fixing ribs. The airflow inside the air guide channel has a higher velocity than the airflow inside the main stator body, meaning the air pressure inside the air guide channel is lower than the air pressure inside the main stator body. Since the exhaust vent is directly connected to the ventilation holes on the hollow ventilation frame, the airflow inside the main stator body enters the exhaust vent through the ventilation holes, then enters the air guide channel, and is discharged from the front of the air guide channel, accelerating the cooling airflow velocity on the outer wall of the main stator body and dissipating heat. The heated air flowing out from the middle of the main stator body will enter the air gap area between the main rotor and the main stator, or mix with other hot air in front. Finally, all the hot air is drawn together by the strong negative pressure generated by the cooling fan blades and quickly discharged from the front cover, completing the entire cooling cycle.

[0020] The main stator includes a hollow ventilation frame, which is a hollow cylinder. The hollow ventilation frame is engaged with several stator fixing ribs. The main stator body is located inside the hollow ventilation frame. Several sets of circumferentially distributed and penetrating ventilation holes are opened on both the main stator body and the hollow ventilation frame. The ventilation holes of the main stator body and the ventilation holes of the hollow ventilation frame are corresponding and connected. Each set of ventilation holes corresponds to the position of the stator fixing ribs, and the ventilation holes are connected to the exhaust holes at the corresponding positions.

[0021] Using the above structure, the hollow ventilation frame is used to accommodate and support the main stator body; it engages between several stator fixing ribs, serving a radial positioning and fixing function, and simultaneously acts as a structural interface and airflow distributor connecting the air duct of the casing to the stator core; forming a continuous cooling path. Several sets of evenly distributed circumferential ventilation holes are correspondingly opened on the hollow ventilation frame and the main stator body. These ventilation holes penetrate both, and are axially corresponding and connected. Each set of ventilation holes is aligned and connected to a corresponding stator fixing rib and its exhaust hole on the casing body. After the cooling airflow enters the casing body from the rear end, a portion is guided into the air guide channel of the stator fixing rib. The airflow flows inside the air guide channel, and its flow velocity is greater than that of the airflow inside the main stator body. The air pressure inside the air guide channel is lower than the air pressure inside the main stator body. Since the exhaust vent is directly connected to the ventilation holes on the hollow ventilation frame, the airflow inside the main stator body enters the exhaust vent through the ventilation holes, then enters the air guide channel, and is discharged from the front of the air guide channel. When the cooling airflow passes through the inside of the main stator body, it undergoes full and direct heat exchange with the high heat density silicon steel sheets, efficiently carrying away the heat generated inside the iron core of the main stator body. The heated air flowing out from the ventilation holes at the front of the main stator body will enter the air gap area between the main rotor and the main stator, or mix with other cooling airflows in front. Finally, all the hot air is drawn together by the strong negative pressure generated by the cooling fan blades and quickly discharged from the front cover, completing the entire cooling cycle.

[0022] The front cover includes a front rear flange and a front front cover flange. The front rear flange is detachably connected to the front end of the front flange of the housing. Several circumferentially distributed connecting and fixing ribs are fixed between the front rear flange and the front front cover flange. The cross-section of the connecting and fixing ribs is a parallelogram. The short side of the connecting and fixing ribs is parallel to the exhaust direction. A lifting lug is fixed at the upper end between the front rear flange and the front front cover flange. The inner side of the front rear flange and the front front cover flange are provided with placement grooves. The two placement grooves form a locking groove.

[0023] With the above structure, the front cover is detachably and tightly connected to the front flange of the main body housing via its rear flange, together forming the front sealing surface of the generator main chamber, preventing internal airflow leakage and the entry of external foreign objects. The rear flange of the front cover and the front flange of the front cover are connected by a ring of connecting and fixing ribs, forming an annular, skeleton-like cavity. This cavity is the transition and diffusion space for hot airflow to gather from the inside of the front cover and finally be discharged. The lifting lugs at the top of the front cover provide a safe and reliable force point for the hoisting, transportation, and installation of the entire generator. The cross-section of all connecting and fixing ribs is a parallelogram. When the cooling fan drives the hot airflow to gather and be discharged from the front cover, its preset exhaust direction is parallel to the short side of the parallelogram rib, so that the projected area of ​​the airflow on the windward side is minimized when the airflow passes through the rib, similar to the airfoil or streamlined design of an aircraft. The function of this design is to effectively divide the airflow and gather the hot airflow. The hot airflow is smoothly divided into multiple streams and guided to flow out through the windows between the ribs; reducing eddies and resistance, the smooth geometry avoids the sharp turbulence and air eddies generated at the air outlet by traditional square or fan-shaped connecting ribs, reducing local resistance loss in the air outlet; improving the overall efficiency of the air outlet, due to the reduced air outlet resistance, it can drive a larger cooling airflow or reduce the fan load with the same power consumption of the cooling fan blades, thereby improving the efficiency of the entire cooling air outlet and ensuring a smoother "through-draft" effect; the placement slots set on the inner side of the front cover together form a locking groove; this structure is used to securely and accurately install the air outlet grille; the air outlet grille plays a role in safety protection and guiding the final direction of airflow; all the hot airflow from inside the main body of the casing eventually converges into the cavity inside the front cover, and under the negative pressure suction continuously generated by the cooling fan blades, the hot airflow is quickly discharged through the low-resistance window of the front cover.

[0024] The air outlet mesh cover includes a mesh cover body, which is snapped into the snap-fit ​​groove. The thickness of the mesh cover body is equal to the depth of the placement groove. The mesh cover body is cylindrical and has a clearance hole. A lifting lug extends out of the clearance hole. The mesh cover body has several sets of circumferentially distributed air outlets. Several sets of circumferentially distributed forward-tilted air guide vanes are fixed to the outside of the mesh cover body. The number and position of the air guide vanes correspond to the air outlets. The air guide vanes are located in front of the corresponding air outlets. Both ends of the mesh cover body are provided with locking plates that are perpendicular to their centers. The two locking plates are directly opposite each other and there are several sets of locking screws between them.

[0025] Using the above structure, the main body of the mesh cover and its air outlet form a physical barrier, and the air guide vanes further block the air outlets, effectively preventing external foreign objects from entering the rapidly rotating heat dissipation fan area, while also blocking any debris that may fly out from inside, ensuring operational safety. The main body of the mesh cover is firmly locked to the front cover by locking plates and locking screw pairs at both ends, ensuring that the air outlet mesh cover will not loosen or fall off under vibration. At the same time, its thickness is equal to the depth of the placement groove, so that after installation, the outer surface of the mesh cover is flush with the outer edge of the front cover or forms a stable fit, resulting in a neat and sturdy structure. By precisely avoiding the holes to expose the lifting lugs, the air guide vanes are tilted forward, with each vane located in front of an air outlet, achieving directional airflow. Diffusion and airflow guidance: When hot air is rapidly ejected from the windows between the internal connecting and fixing ribs and impacts the air guide vanes, the rear-to-front angle guides the airflow to change direction, causing it to diffuse and spray diagonally forward. This guided airflow can more effectively prevent hot air from flowing back to the air intake of the generator, affecting cooling efficiency. At the same time, it helps guide the airflow away from the generator's near-body area as quickly as possible, reducing the backflow or vortex of hot air near the air outlet, thereby helping to reduce the outlet resistance of the entire exhaust system. In coordination with the low-drag front end, the air outlet mesh is installed outside the front cover with parallelogram low-drag connecting and fixing ribs. The ribs of the front cover are responsible for integrating the internal turbulence into a relatively smooth and concentrated airflow and initially reducing resistance.

[0026] The cooling fan blades include a frustum-shaped impeller. An integrally formed flat key is provided inside the mounting hole of the impeller. The mounting hole and the integral flat key are fitted together and installed on the main shaft. The rear end face of the impeller is provided with several L-shaped blades evenly distributed around the circumference. The front end face of the blades is provided with a reinforcing ring. The rear end face of the blades is provided with a reinforcing base plate. The front end face of the impeller is provided with several reinforcing ribs evenly distributed around the circumference.

[0027] With the above structure, the blades are L-shaped, and the middle part is recessed according to the height and outer diameter of the protruding winding at the front end of the generator's main stator. This allows the front winding of the main stator body to be enclosed within it, thereby reducing the axial length of the generator to a certain extent and improving the heat dissipation of the generator stator winding. The reinforcing base plate reinforces the blades, ensuring their stability during rapid rotation and enhancing overall strength. The impeller adopts a frustum-shaped design, with a streamlined arc on its back outer wall for airflow guidance. A mounting hole is provided in the center, with the hole diameter matching the outer diameter of the main shaft blade mounting position. The integrated flat key eliminates the need for a separate key during installation, allowing direct mating with the keyway on the main shaft, facilitating the installation of the cooling fan blades and ensuring dimensional stability. Reinforcing ribs ensure the strength of the through holes and the overall impeller. The reinforcing ring further strengthens the overall strength of the cooling fan blades, ensuring their stability during operation.

[0028] The rear end cover includes a rear end cover body, with a lifting lug 2 fixed to the upper end of the rear end cover body. The rear end cover body has several circumferentially distributed mounting through holes 2. The rear end cover body is detachably mounted at the rear end of the rear flange of the housing by several mounting bolts passing through the corresponding mounting through holes 2. The middle part of the rear end cover body has a bearing seat provided by four supporting ribs, and the bearing is located inside the bearing seat. The front end of the rear end cover body has four symmetrically arranged connecting seats, each with mounting screw holes. The rear end of the rear end cover body has a placement groove, and the rear cover is detachably mounted inside the placement groove. The thickness of the rear cover is equal to the depth of the placement groove. The front side of the rear cover has several rear cover filters, which extend into the interior of the rear end cover body.

[0029] With the above structure, the rear cover body has a bearing seat in the middle of the main body through four supporting ribs, in which the bearing is installed. The core support point at the rear end of the main shaft, together with the front cover, ensures the stability and concentric rotation of the main shaft, which is the basis for uniform magnetic gap and smooth mechanical operation. The four connecting seats and their mounting screw holes are used to fix the excitation stator. The rear cover is firmly connected to the rear flange of the housing through the mounting through hole two and the mounting bolts to form a complete body. The upper lifting lug two and the front cover lifting lug one together provide a lifting support point for the generator. The placement groove is used to install the rear cover cover. The depth matching design of the two ensures flatness and stability after installation. The rear cover body is not a closed end plate. Its bearing seat is connected to the outer frame only through four radial supporting ribs. The spoke design makes the large area between the supporting ribs a natural and largest air intake opening. Several rear cover filters effectively block dust, lint and other large particulate pollutants from entering the generator, protecting the heat dissipation duct, rotor blades and electromagnetic components, and ensuring the long-term efficient and reliable operation of the cooling system.

[0030] The excitation stator includes an excitation stator ring frame, on which several mounting through holes are provided. The number and position of the mounting through holes correspond to the number and position of the mounting screw holes. The mounting through holes and the corresponding mounting screw holes are connected by connecting bolts. The inner side of the excitation stator ring frame is provided with several circumferentially distributed excitation stator seats integrally formed therewith. Each excitation stator seat and the excitation stator ring frame are provided with a through air guide hole. The excitation stator seat is provided with an excitation winding.

[0031] With the above structure, the excitation winding is the input terminal of the excitation circuit. The automatic voltage regulator outputs a controllable DC current to it based on the generator output voltage feedback. After being energized, the coil generates an adjustable static magnetic field in the magnetic circuit formed by the excitation stator base and the excitation stator ring frame. This static magnetic field is the source of subsequent brushless excitation energy transfer. It is cut by the armature winding on the coaxially rotating excitation rotor, inducing AC current in the excitation rotor. The excitation stator ring frame is fastened to the mounting screw holes on the front end of the rear end cover using connecting bolts through its mounting through-holes. An auxiliary ventilation path is formed to reduce wind resistance: each excitation stator base and the excitation stator ring frame has a through-hole. A portion of the annular axial main air duct formed by the large-diameter differential rotor passes through the excitation stator area. The air ducts allow the cooling airflow to flow smoothly forward through these holes when passing through this area, instead of being completely blocked by the solid stator structure. This reduces... The airflow contraction and resistance at this location prevent airflow from forming eddies or blockages, ensuring the continuity of the "straight airflow." The airflow passing through the air guide holes can directly contact and cool the excitation stator base and the excitation windings surrounding it, promptly carrying away the heat generated by the excitation stator itself during operation and preventing local overheating. It is not only a heat source, but also actively integrates into the cooling airflow through its air guide hole design. Clean cooling air from the rear end cover, when entering the annular main airflow through the excitation component area, part of it passes through the excitation stator structure through the air guide holes, both cooling itself and maintaining the low resistance and smooth flow of the airflow, consistent with the open air intake design of the rear end cover. The stable static magnetic field generated is cut by the rotating excitation rotor, and after being rectified by the rotating rectifier bridge, it provides the DC excitation current required to establish the main magnetic field for the main rotor, which is a key link in completing the brushless energy transfer. Its robust installation method ensures mechanical stability under extremely small axial spacing, supporting the entire "flat" structure.

[0032] The difference between the diameter of the main rotor and the diameter of the excitation rotor is greater than or equal to 150 mm.

[0033] With the above structure, the diameter of the main rotor is larger than that of the excitation rotor, creating conditions for their staggered arrangement in radial space. The excitation rotor and the excitation stator are "nested" in the radial space behind the main rotor, naturally forming a large cross-sectional area, a straight flow channel, and an almost bendless annular axial space, creating a highly efficient straight axial cooling air channel for efficient heat dissipation. This annular axial space constitutes the main air channel of the cooling system. After entering from the open rear end cover, the cooling air can pass directly through this channel, directly scouring the working air gap between the main stator and the main rotor. The airflow is smooth and the resistance is minimal, effectively avoiding eddies and forming a highly efficient "through-draft" effect, laying the physical foundation for the overall heat dissipation of the machine.

[0034] The outlet box includes two end plates arranged symmetrically front and back. The end plates are respectively fixed to the outer side of two mounting plates on the same side. The lower end of the end plate is provided with an arc-shaped notch that fits tightly against the main body of the casing. Side plates are detachably provided on the left and right sides of the two end plates by screws. Top plates are detachably provided on the upper end of the two end plates and the two side plates by screws. An automatic voltage regulator is detachably provided on the inner side of one of the side plates by screws.

[0035] With the above structure, the internal space of the terminal box mainly accommodates the terminal block, which is the connection hub between the generator's internal power cables and external load cables, and is a critical electrical node for high voltage and high current. The terminal box provides it with a closed, dustproof, and accident-proof safe space to ensure operational safety and the reliability of electrical connections. The inner side of one of the side plates of the terminal box is specifically designed for the detachable installation of an automatic voltage regulator via screws, responsible for monitoring the output voltage and adjusting the excitation current to maintain voltage stability. The arc-shaped notch at the lower end of the end plate allows it to fit tightly against the upper surface of the main body of the casing, ensuring the high stability of the terminal box under generator operating vibration environments, while also enhancing the bottom... The junction box is dustproof and splashproof. The top and side panels of the junction box are connected to the end plates with screws, forming a hexagonal structure with four fully openable sides. This design allows for easy maintenance by removing only the corresponding panel during wiring checks, fuse replacement, maintenance, or replacement of automatic voltage regulators and terminal blocks, without disassembling the entire junction box. A clearance hole at the top of the main housing is located below the internal space of the junction box. All lead-out cables from the main stator and excitation stator enter the junction box directly and via a short path through this clearance hole, connecting to the terminal block. The junction box provides a safe and orderly transition and containment space between the inside of the main housing and the external load.

[0036] Compared with existing technologies, this flat, compact generator has the following advantages:

[0037] This invention employs a large-diameter differential rotor to achieve a radially nested layout, combined with an axially overlapping design where cooling fan blades encircle the stator windings, shortening the axial dimension and achieving a truly flattened overall structure. Based on the wide, straight, annular axial main air duct naturally formed by the large-diameter differential, combined with low-resistance inlet and outlet designs, a highly efficient cooling system is constructed; the airflow path is short, resistance is low, and there are no vortices, improving the basic heat dissipation efficiency. An auxiliary cooling system using "hollow fixed ribs - through-hole ventilation" guides airflow to carry away heat from the main stator body, resulting in a more uniform temperature distribution. The air guide hole design on the excitation stator ensures both its own cooling and unobstructed flow of the main air duct through the excitation area, preventing airflow blockage. While achieving a compact design, it also ensures structural strength, ease of installation, and convenient maintenance. Attached Figure Description

[0038] Figure 1This is a schematic diagram of the overall three-dimensional structure of Embodiment 1 of the present invention.

[0039] Figure 2 This is a schematic diagram of the overall exploded structure of Embodiment 1 of the present invention.

[0040] Figure 3 This is a three-dimensional structural diagram of the air outlet mesh cover in Embodiment 1 of the present invention.

[0041] Figure 4 This is a three-dimensional structural diagram of the front cover of Embodiment 1 of the present invention.

[0042] Figure 5 This is a cross-sectional view of the front cover and a schematic diagram of the airflow path in Embodiment 1 of the present invention.

[0043] Figure 6 This is a three-dimensional structural diagram of the main stator and housing in Embodiment 1 of the present invention.

[0044] Figure 7 This is a cross-sectional structure and airflow diagram of the casing in Embodiment 1 of the present invention.

[0045] Figure 8 This is a three-dimensional structural diagram of the main stator in Embodiment 1 of the present invention.

[0046] Figure 9 This is a three-dimensional structural diagram of the rear end cover and excitation stator in Embodiment 1 of the present invention.

[0047] Figure 10 This is a three-dimensional structural diagram of the rear end cover of Embodiment 1 of the present invention.

[0048] Figure 11 This is a three-dimensional structural diagram of the heat dissipation fan blade in Embodiment 1 of the present invention.

[0049] Figure 12 This is a three-dimensional structural diagram of the main stator and housing in Embodiment 2 of the present invention.

[0050] Figure 13 This is a three-dimensional structural diagram of the main stator in Embodiment 2 of the present invention.

[0051] In the diagram, 1. Housing; 2. Exhaust grille; 3. Front cover; 4. Disc coupling; 5. Locking plate; 6. Cooling fan blades; 7. Terminal box; 8. Rear cover; 9. Locking screws; 10. Main shaft; 11. Main rotor; 12. Main stator; 13. Excitation rotor; 14. Rectifier bridge; 15. End plate; 16. Automatic voltage regulator; 17. Side plate; 18. Top plate; 19. Terminal block; 20. Excitation stator; 21. Bearing; 22. Rear cover; 23. Rear cover filter; 24. Grille body; 25. Avoidance hole; 26. Air guide vane; 27. Air outlet; 28. Locking plate; 29. ​​Locking screw set; 30. Front rear flange; 31. Connecting fixing rib; 32. Placement slot; 33. Front flange of front cover; 34. Lifting lug 1; 5. Mounting base; 36. Main casing; 37. Clearance hole; 38. Mounting plate; 39. Base; 40. Front flange of casing; 41. Rear flange of casing; 42. Stator fixing rib; 43. Air guide channel; 44. Main stator body; 45. Hollow ventilation frame; 46. Ventilation hole; 47. Lifting lug 2; 48. Connecting seat; 49. Excitation stator ring frame; 50. Excitation stator base; 51. Excitation winding; 52. Air guide hole; 53. Mounting through hole 1; 54. Mounting bolt; 55. Rear end cover body; 56. Mounting through hole 2; 57. Mounting screw hole; 58. Bearing seat; 59. Bearing bracket; 60. Exhaust hole; 61. Blade; 62. Reinforcing base plate; 63. Reinforcing ring; 64. Integrated flat key; 65. Reinforcing rib; 66. Impeller. Detailed Implementation

[0052] The following are specific embodiments of the present invention described in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments. Example

[0053] like Figures 1-11As shown, this flat, compact generator includes a front cover 3, a housing 1, a rear cover 8, and a rear cover 22 connected sequentially from front to back. The front cover 3 has an exhaust grille 2 on its exterior. The housing 1 has a terminal block 19 and a terminal box 7 on its upper exterior. The terminal block 19 is located inside the terminal box 7. An automatic voltage regulator 16 is located inside the terminal box 7. A main stator 12 is fixed inside the housing 1. An excitation stator 20 is located at the front end of the rear cover 8, inside the housing 1 and behind the main stator 12. The rear cover 22 is located at the rear end of the rear cover 8. A bearing 21 is located inside the rear cover 8. The inner ring of the bearing 21... The main shaft 10 is fixed inside. The front end face of the main shaft 10 is provided with several closely fitting disc couplings 4 and a locking plate 5 in sequence from back to front via locking screws 9. The main shaft 10 is provided with a cooling fan 6, a main rotor 11 and an excitation rotor 13 in sequence from front to back. The cooling fan 6 is located inside the front end cover 3. The main rotor 11 is located inside the main stator 12 and is electromagnetically coupled to the main stator 12. The excitation rotor 13 is located inside the excitation stator 20 and is electromagnetically coupled to the excitation stator 20. The rear end face of the excitation rotor 13 is provided with a rectifier bridge 14. The terminal block 19 is electrically connected to the main stator 12 and the excitation stator 20.

[0054] The excitation stator 20 and excitation rotor 13 assemblies are nested within the radial space behind the main rotor 11, allowing the axial distance between the main and excitation parts to be minimized. A wide and unobstructed annular axial airflow channel is formed between the main rotor 11 and the excitation rotor 13. After being filtered by the rear cover 22, the clean air enters the housing 1 from the rear end cover 8. Most of the cooling airflow flows straight forward through the annular space between the excitation rotor 13 and the excitation stator 20, flushing the air gap between the main stator 12 and the main rotor 11. This straight path effectively avoids the generation of eddies; some airflow flows forward along the annular gap between the inner wall of the casing 1 and the outer circle of the main stator 12, and the casing 1 assists in the airflow, directly guiding the cold air to the main stator 12, thereby enhancing the cooling of the main stator 12; all the heated airflow is driven by the heat dissipation fan blades 6 (which rotate rapidly with the main shaft 10) to converge towards the front cover 3, reducing the air outlet resistance, and the hot air is finally smoothly discharged outside the machine through the air outlet screen 2 and blown out obliquely forward, avoiding the hot air from flowing back to the air inlet of the generator and affecting the cooling efficiency;

[0055] Main power generation circuit: The prime mover (such as a diesel engine) drives the main shaft 10 to rotate through the disc coupling 4, which drives the cooling fan 6, the main rotor 11 and the excitation rotor 13 to rotate together. After the winding on the main rotor 11 is energized with DC current, a rotating magnetic field is generated. This magnetic field cuts the three-phase armature winding of the main stator 12, thereby inducing a three-phase AC electromotive force in the main stator, and outputting electrical energy through the terminal block 19.

[0056] Excitation power supply: The automatic voltage regulator 16 outputs an adjustable DC current to the excitation winding of the stationary excitation stator 20 based on the feedback signal of the generator output voltage.

[0057] Rotary rectification: The static magnetic field generated by the excitation stator 20 is cut by the armature winding on the coaxially rotating excitation rotor 13, inducing three-phase alternating current in the excitation rotor 13. This alternating current is immediately converted into direct current by the rotary rectifier bridge 14 installed at the rear end of the excitation rotor.

[0058] Magnetic field establishment: The rectified DC power is directly supplied to the excitation winding of the main rotor 11 through the connection of the main shaft 10 or a dedicated wire, thereby establishing the main rotating magnetic field and completing the excitation energy transfer of the brushless system.

[0059] Throughout the process, the automatic voltage regulator 16 continuously monitors the generator output voltage. When load changes cause voltage fluctuations, the automatic voltage regulator 16 quickly adjusts the magnitude of the DC current supplied to the excitation stator 20, thereby changing the excitation intensity and ultimately stabilizing the main generator output voltage.

[0060] The housing 1 includes a housing body 36. Two symmetrically arranged mounting bases 35 are fixed to the lower end of the housing body 36. Two symmetrically arranged clearance holes 37 are opened at the upper end of the housing body 36. A base 39 and four symmetrically arranged mounting plates 38 are fixed to the upper end of the housing body 36. The base 39 is located between the two clearance holes 37. The wiring board 19 is detachably mounted on the upper end of the base 39 by screws. The two corresponding mounting plates 38 are located on the front and rear sides of the clearance holes 37 respectively. A front flange 40 is fixed to the front side of the housing body 36, and a rear flange 41 is fixed to the rear side of the housing body 36. Several circumferentially distributed stator fixing ribs 42 are provided inside the housing body 36. The interior of the stator fixing ribs 42 is hollow to form an air guide channel 43. Several exhaust holes 60 are opened on the stator fixing ribs 42. The length of the stator fixing ribs 42 is less than the length of the housing body 36.

[0061] The main body 36 of the generator forms the main chamber of the generator, which is used to house and fix the core electromagnetic components such as the main stator 12 and the main rotor 11, and is the mechanical foundation of the generator. The two mounting seats 35 at the lower end provide the support points for the entire generator to connect to the foundation or mobile platform (such as the chassis). The base 39 at the upper end is used to install the terminal block 19, while the four mounting plates 38 provide the installation interface for the outlet box 7. The front flange 40 of the housing at the front end and the rear flange 41 of the housing at the rear end are used to achieve a sealed and firm connection with the front cover 3 and the rear cover 8, respectively, forming a completely closed motor cavity. The two clearance holes 37 at the upper end provide the channels for the lead cables of the main stator 12 and the excitation stator 20 to the outlet box 7. Several stator fixing ribs 42 are evenly distributed around the circumference, and their interiors are designed as hollow structures, which are the air guide channels 43. When the cooling airflow enters the main body of the housing from the rear cover 8... After entering the main air duct, a portion of the airflow, except for the gap between the main air duct and the inner wall of the main body 36, will be guided into the air guide channel 43. The length of the stator fixing rib 42 is less than the length of the main body 36, and its end is open, which facilitates air inlet and outlet. The airflow enters the air guide channel 43 and forms a negative pressure. Under the action of air pressure difference, the hot air on the outer surface of the back of the main stator 12 is drawn into the air guide channel 43 through several exhaust holes 60 and discharged from the main body 36, improving the heat dissipation efficiency of the main stator 12 and making the temperature field distribution inside the motor more uniform. The stator fixing rib 42 and the main air duct work in synergy and parallel, forming a three-dimensional cooling network with clear primary and secondary components and comprehensive coverage (air gap, end, back of the main stator 12). All the airflow entering the main body 36 is finally drawn together and discharged to the periphery of the front cover 3 under the negative pressure suction generated by the heat dissipation fan 6.

[0062] The main stator 12 includes a hollow ventilation frame 45, which is open at both ends. The hollow ventilation frame 45 is engaged with several stator fixing ribs 42. The main stator body 44 is located inside the hollow ventilation frame 45. Several sets of circumferentially distributed and penetrating ventilation holes 46 are opened on the hollow ventilation frame 45. Each set of ventilation holes 46 corresponds to the position of the stator fixing ribs 42, and the ventilation holes 46 are connected to the exhaust holes 60 at the corresponding positions.

[0063] The main stator body 44 is the core armature of the generator, made of laminated silicon steel sheets and embedded with three-phase windings. During operation, it generates a large amount of heat due to iron losses (hysteresis, eddy currents) and copper losses (winding resistance), making it the main heat source. The hollow ventilation frame 45, open at both ends, accommodates and supports the main stator body 44, engaging between several stator fixing ribs 42, serving as radial positioning and fixation. It also acts as a structural interface and airflow distributor connecting the air duct of the housing 1 to the main stator body 44, forming a continuous cooling path. Several sets of evenly distributed circumferential ventilation holes 46 are correspondingly opened on the hollow ventilation frame 45 and the main stator body 44. Each set of ventilation holes 46 is aligned and connected to a corresponding stator fixing rib 42 and its exhaust hole 60 on the housing body 36. After the cooling airflow enters the housing body 36 from the rear end, a portion is guided into the airflow channel of the stator fixing rib 42. 43. The airflow flows inside the air guide channel 43, and its flow speed is greater than that inside the main stator body 44, that is, the air pressure inside the air guide channel 43 is lower than that inside the main stator body 44. Since the exhaust hole 60 is directly connected to the ventilation hole 46 on the hollow ventilation frame 45, the airflow inside the main stator body 44 enters the exhaust hole 60 through the ventilation hole 46, and then enters the air guide channel 43, and is discharged from the front of the air guide channel 43, which accelerates the cooling airflow speed on the outer wall of the main stator body 44 and dissipates heat from the outer wall of the main stator body 44. The heated air flowing out from the middle of the main stator body 44 will enter the air gap area between the main rotor 11 and the main stator 12, or mix with other hot air in front. Finally, all the hot air is collected under the strong negative pressure suction generated by the cooling fan 6 and is quickly discharged from the front cover 3, completing the entire cooling cycle.

[0064] The front cover 3 includes a front rear flange 30 and a front front cover flange 33. The front rear flange 30 is detachably connected to the front end of the front flange 40 of the housing. Several circumferentially distributed connecting and fixing ribs 31 are fixed between the front rear flange 30 and the front front cover flange 33. The cross-section of the connecting and fixing ribs 31 is a parallelogram. The short side of the connecting and fixing ribs 31 is parallel to the exhaust direction. A lifting lug 34 is fixed at the upper end between the front rear flange 30 and the front front cover flange 33. The inner side of the front rear flange 30 and the front front cover flange 33 are provided with placement grooves 32. The two placement grooves 32 form a locking groove.

[0065] The front cover 3 is detachably (usually bolted) tightly connected to the front flange 40 of the main body 36 via its rear flange 30, together forming the front sealing surface of the generator main chamber to prevent internal airflow leakage and the entry of external foreign objects. The rear flange 30 and the front flange 33 of the front cover are connected by a ring of connecting and fixing ribs 31 to form an annular, skeleton-like cavity. This cavity is the transition and diffusion space for hot airflow to gather from the inside of the front cover to the final discharge. The lifting lug 34 at the top of the front cover 3 provides a safe and reliable force point for the hoisting, transportation and installation of the entire generator. The cross-section of all connecting and fixing ribs 31 is a parallelogram. When the cooling fan 6 drives the hot airflow to gather and discharge towards the front cover, its preset exhaust direction is parallel to the short side of the parallelogram rib. This design minimizes the projected area of ​​the airflow on the windward side when it flows through the rib, similar to the airfoil or streamlined design of an aircraft.

[0066] The design functions to: effectively divide airflow, smoothly splitting concentrated hot airflow into multiple streams and guiding it out through the windows between the ribs; reduce eddies and resistance, with the smooth geometry avoiding sharp turbulence and air eddies generated at the air outlet by traditional square or fan-shaped connecting ribs 31, thus reducing local resistance loss in the air outlet; and improve the overall efficiency of the air outlet, as the reduced air outlet resistance allows for a larger cooling airflow or a reduced fan load under the same power consumption of the cooling fan blades 6, thereby improving the efficiency of the entire cooling air outlet and ensuring a smoother "through-draft" effect.

[0067] The placement groove 32 provided on the inner side of the front cover 3 (the inner side of the front rear flange 30 and the front flange 33 of the front cover) together form a locking groove; this structure is used to securely and accurately install the air outlet screen 2; the air outlet screen 2 serves to provide safety protection (prevent foreign objects from entering or the human body from touching the internal rotating parts) and guide the final direction of airflow; all the hot airflow from inside the casing 36 eventually converges into the cavity inside the front cover 3, and under the continuous negative pressure suction generated by the heat dissipation fan 6, the hot airflow is quickly discharged.

[0068] The air outlet mesh cover 2 includes a mesh cover body 24, which is snapped into the snap-fit ​​groove. The thickness of the mesh cover body 24 is equal to the depth of the placement groove 32. The mesh cover body 24 is cylindrical and has a clearance hole 25. A lifting lug 34 extends out of the clearance hole 25. The mesh cover body 24 has several sets of circumferentially distributed air outlets 27. Several sets of circumferentially distributed forward-tilted air guide vanes 26 are fixed to the outside of the mesh cover body 24. The number and position of the air guide vanes 26 correspond to the air outlets 27. The air guide vanes 26 are located in front of the corresponding air outlets 27. Both ends of the mesh cover body 24 are provided with locking plates 28 that are perpendicular to their centers. The two locking plates 28 are directly opposite each other and there are several locking screw pairs 29 between them.

[0069] The main body 24 of the mesh cover and the air outlet 27 on it form a physical barrier, and the air guide 26 further blocks the air outlet 27, effectively preventing foreign objects (such as tools and fingers) from entering the area of ​​the rapidly rotating heat dissipation fan blades 6, and also blocking debris that may fly out from inside, ensuring operational safety; the main body 24 of the mesh cover is firmly locked to the front cover 3 by the locking plates 28 and locking screw pairs 29 at both ends, ensuring that the air outlet mesh cover 2 will not loosen or fall off in a vibration environment; at the same time, its thickness is equal to the depth of the placement groove 32, so that after installation, the outer surface of the mesh cover is flush with the outer edge of the front cover or forms a stable fit, with a neat and sturdy structure; the avoidance hole 25 precisely exposes the lifting lug 34, and the air guide 26 is inclined forward (i.e., the inclined direction points away from the main body 36 of the casing). Each air guide 26 is located in front of an air outlet 27;

[0070] Achieving directional diffusion: airflow guidance. When hot air is rapidly ejected from the window between the internal connecting and fixing ribs 31 and hits the air guide 26, the rear-forward angle will guide the airflow to change direction, causing it to diffuse and spray diagonally forward (i.e. away from the outer surface of the casing 1). This guided airflow can more effectively prevent hot air from flowing back to the air inlet of the generator, affecting the cooling efficiency. At the same time, it helps to guide the airflow away from the near-body area of ​​the generator as soon as possible, reducing the backflow or vortex of hot air near the air outlet, thereby helping to reduce the outlet resistance of the entire exhaust system.

[0071] In conjunction with the low-drag front end, the air outlet mesh 2 is installed outside the front cover 3, which has a parallelogram-shaped low-drag connecting fixing rib 31; the ribs of the front cover 3 are responsible for integrating the internal turbulence into a relatively smooth and concentrated airflow and initially reducing resistance.

[0072] The cooling fan blade 6 includes a frustum-shaped impeller 66. An integrally formed flat key 64 is provided inside the mounting hole of the impeller 66. The mounting hole of the impeller 66 and the integral flat key 64 are fitted together and installed on the main shaft 10. The rear end face of the impeller 66 is provided with several circumferentially distributed L-shaped blades 61. The front end face of the blades 61 is provided with a reinforcing ring 63. The rear end face of the blades 61 is provided with a reinforcing base plate 62. The front end face of the impeller 66 is provided with several circumferentially distributed reinforcing ribs 65.

[0073] The blade 61 is L-shaped, with a recessed section in its middle designed to accommodate the height and outer diameter of the protruding winding at the front end of the generator's main stator. This recess encloses the front winding of the main stator body 44, thus reducing the axial length of the generator to some extent and improving heat dissipation of the generator stator winding. The reinforcing base plate 62 reinforces the blades, ensuring stability of the blades 61 during rapid rotation and enhancing overall strength. The impeller 66 adopts a frustum shape design, with a streamlined arc on its back outer wall for airflow guidance. A mounting hole is provided in the center, with its diameter matching the outer diameter of the blade mounting position on the main shaft 10. The integrated flat key 64 eliminates the need for a separate key during installation, allowing direct engagement with the keyway on the main shaft 10, facilitating the installation of the cooling fan 6 and ensuring dimensional stability. The reinforcing rib 65 ensures the overall strength of the through hole and the impeller 66. The reinforcing ring 63 further strengthens the overall strength of the cooling fan 6, ensuring its stability during operation.

[0074] The rear cover 8 includes a rear cover body 55. A second lifting lug 47 is fixed to the upper end of the rear cover body 55. Several circumferentially distributed mounting through holes 56 are provided on the rear cover body 55. The rear cover body 55 is detachably mounted on the rear end of the rear flange 41 of the housing by several mounting bolts 54 passing through the corresponding mounting through holes 56. A bearing seat 58 is provided in the middle of the rear cover body 55 by four supporting ribs. The bearing 21 is located inside the bearing seat 58. Four symmetrically arranged connecting seats 48 are provided at the front end of the rear cover body 55. Each connecting seat 48 is provided with a mounting screw hole 57. A placement groove is provided at the rear end of the rear cover body 55. The rear cover cover 22 is detachably mounted inside the placement groove. The thickness of the rear cover cover 22 is equal to the depth of the placement groove. Several rear cover filter screens 23 are provided on the front side of the rear cover cover 22. The rear cover filter screens 23 extend into the interior of the rear cover body 55.

[0075] The rear cover body 55 has a bearing seat 58 in the middle supported by four ribs, in which the bearing 21 is installed. This is the core support point at the rear end of the main shaft 10, working together with the front cover 3 to ensure the stability and concentric rotation of the main shaft 10. This is fundamental to ensuring uniform electromagnetic air gap and smooth mechanical operation. Four connecting seats 48 and their mounting screw holes 57 are used to fix the excitation stator 20. The rear cover 8 is firmly connected to the rear flange 41 of the housing through the mounting through hole 56 and mounting bolts 54, forming a complete machine body. The upper lifting lug 47 and the front cover 3's lifting lug 34 together provide... The generator provides a hoisting support point; the placement slot is used to install the rear cover 22, and the depth matching design of the two ensures flatness and stability after installation; the rear cover body 55 is not a closed end plate, and its bearing seat 58 is connected to the outer frame only through four radial support ribs. The spoke-like design makes the large area between the support ribs a natural and largest air intake opening; several rear cover filters 23 effectively block larger particulate pollutants such as dust and lint from entering the generator, protecting the heat dissipation duct, rotor blades and electromagnetic components, and ensuring long-term efficient and reliable operation of the cooling system.

[0076] The excitation stator 20 includes an excitation stator ring frame 49, on which a plurality of mounting through holes 53 are provided. The number and position of the mounting through holes 53 correspond to the number of mounting screw holes 57. The mounting through holes 53 and the corresponding mounting screw holes 57 are connected by connecting bolts. The inner side of the excitation stator ring frame 49 is provided with a plurality of circumferentially distributed excitation stator seats 50 integrally formed therewith. Each excitation stator seat 50 and the excitation stator ring frame 49 are provided with a through air guide hole 52. The excitation stator seat 50 is provided with an excitation winding 51.

[0077] The excitation winding 51 is the input terminal of the excitation circuit. The automatic voltage regulator 16 outputs a controllable DC current to it based on the generator output voltage feedback. After being energized, the coil generates a static (non-rotating) magnetic field with adjustable intensity in the magnetic circuit formed by the excitation stator base 50 and the excitation stator ring frame 49. This static magnetic field is the source of subsequent brushless excitation energy transfer. It is cut by the armature winding on the coaxially rotating excitation rotor 13, inducing AC current in the excitation rotor. The excitation stator ring frame 49 is fastened to the mounting screw hole 57 on the front end connecting seat 48 of the rear end cover 8 through the mounting through hole 53 on it using connecting bolts. An auxiliary ventilation path is formed to reduce wind resistance. Each excitation stator base 50 and excitation stator ring frame A through-hole 52 is provided between 49; the annular axial main air duct formed by the large-diameter differential rotor passes through part of the excitation stator area (the annular space between the excitation rotor 13 and the excitation stator 20). The air guide holes 52 allow the cooling airflow to flow smoothly forward through these holes when it flows through this area, instead of being completely blocked by the solid stator structure; reducing the air duct contraction and resistance at this point, avoiding the formation of vortices or blockages in the airflow, and ensuring the continuity of the "straight air duct"; the airflow flowing through the air guide holes 52 can directly contact and cool the excitation stator base 50 and the excitation winding 51 surrounding it, and timely remove the heat (mainly copper loss) generated by the excitation stator itself during operation, preventing local overheating;

[0078] Synergy with the cooling system: It is not only a heat source, but also actively integrates into the cooling air duct through its air guide hole 52 design. When the clean cooling air from the rear cover 8 enters the annular main air duct and flows through the excitation component area, part of it passes through the excitation stator structure through the air guide hole 52, which cools itself and maintains the low resistance and smooth flow of the air duct, which is consistent with the open air intake design of the rear cover.

[0079] Synergy with the excitation circuit: The static magnetic field generated stably is cut by the rotating excitation rotor 13, and after being rectified by the rotating rectifier bridge 14, it provides the DC excitation current required to establish the main magnetic field for the main rotor 11, which is a key link in completing the brushless energy transfer.

[0080] Synergy with a compact layout: Its robust mounting method ensures mechanical stability with minimal axial spacing, supporting the entire "flat" structure.

[0081] The difference between the diameter of the main rotor 11 and the diameter of the excitation rotor 13 is greater than or equal to 150 mm.

[0082] The diameter of the main rotor 11 is larger than that of the excitation rotor 13, which creates conditions for the two to be staggered in radial space. The excitation rotor 13 and the excitation stator 20 can be "nested" in the radial space behind the main rotor 11, naturally forming an annular axial space with a large cross-sectional area, a straight flow channel, and almost no bends, creating an efficient straight axial cooling air channel for efficient heat dissipation. This annular axial space constitutes the main air channel of the cooling system. After the cooling air enters from the open rear end cover 8, it can pass directly through this channel and directly flush the working air gap between the main stator 12 and the main rotor 11. The airflow is smooth and the resistance is minimal, effectively avoiding eddies and forming an efficient "through wind" effect, laying the physical foundation for the heat dissipation of the whole machine.

[0083] The outlet box 7 includes two end plates 15 arranged symmetrically front to back. The end plates 15 are respectively fixed to the outer side of two mounting plates 38 on the same side. The lower end of the end plate 15 is provided with an arc-shaped notch that fits tightly against the main body 36 of the housing. Side plates 17 are detachably provided on the left and right sides of the two end plates 15 by screws. The upper end of the two end plates 15 and the two side plates 17 is detachably provided with a top plate 18 by screws. The automatic voltage regulator 16 is detachably provided on the inner side of one of the side plates 17 by screws.

[0084] The internal space of the terminal box 7 mainly accommodates the terminal block 19, which is the connection hub between the power cables inside the generator (main stator 12, excitation stator 20) and the external load cables. It is a critical electrical node with high voltage and high current. The terminal box 7 provides a closed, dustproof, and accident-proof safe space to ensure operational safety and the reliability of electrical connections. The inner side of one of the side plates 17 of the terminal box 7 is specifically designed for the detachable installation of an automatic voltage regulator 16 with screws. This regulator monitors the output voltage and adjusts the excitation current to maintain voltage stability. The arc-shaped notch at the lower end of the end plate 15 allows it to fit tightly against the upper surface of the main body 36 of the housing, ensuring the high stability of the terminal box 7 under generator operating vibration conditions, while also enhancing dust and splash protection at the bottom. The top plate 18 and side plates 17 of the outlet box are connected to the end plate 15 by screws, forming a structure in which four sides (top and two side sides) of a hexahedron can be fully opened. This design allows for the removal of the entire outlet box 7 without disassembling it, only the corresponding panel needs to be removed when performing wiring checks, replacing fuses, maintaining or replacing the automatic voltage regulator 16 and the terminal block 19, thus improving the convenience of maintenance. The clearance hole 37 at the upper end of the main body 36 is located below the internal space of the outlet box. All the lead cables of the main stator 12 and the excitation stator enter the interior of the outlet box directly and through the clearance hole 37 via a short path and connect to the terminal block 19. The outlet box provides a safe and orderly transition and accommodation space for these cables from the interior of the main body 36 to the external load. Example

[0085] like Figures 12-13As shown, the main stator 12 has a different structure compared to Embodiment 1.

[0086] The main stator 12 includes a hollow ventilation frame 45, which is a hollow cylinder. The hollow ventilation frame 45 is engaged with several stator fixing ribs 42. The main stator body 44 is provided inside the hollow ventilation frame 45. Several sets of circumferentially distributed and penetrating ventilation holes 46 are provided on both the main stator body 44 and the hollow ventilation frame 45. The ventilation holes 46 of the main stator body 44 and the ventilation holes 46 of the hollow ventilation frame 45 are corresponding and connected. Each set of ventilation holes 46 corresponds to the position of the stator fixing rib 42, and the ventilation holes 46 are connected to the exhaust holes 60 at the corresponding positions.

[0087] The hollow ventilation frame 45 is a structural component, hollow inside, used to accommodate and support the main stator body 44; it engages between several stator fixing ribs 42, serving a radial positioning and fixing function, and also acts as a structural interface and airflow distributor connecting the air duct of the housing 1 and the stator core; forming a continuous cooling path. Several sets of evenly distributed circumferential ventilation holes 46 are correspondingly opened on the hollow ventilation frame 45 and the main stator body 44. These ventilation holes 46 penetrate both, and are axially corresponding and connected. Each set of ventilation holes 46 is aligned and connected to a corresponding stator fixing rib 42 and its exhaust hole 60 on the housing body 36. After the cooling airflow enters the housing body 36 from the rear end, a portion is guided into the air guide channel 43 of the stator fixing rib 42. The airflow flows inside the air guide channel 43, and its flow velocity is greater than that of the airflow inside the main stator body 44, i.e., the airflow is directed into the air guide channel 43. The air pressure inside the air duct 43 is lower than the air pressure inside the main stator body 44. Since the exhaust port 60 is directly connected to the ventilation port 46 on the hollow ventilation frame 45, the airflow inside the main stator body 44 enters the exhaust port 60 through the ventilation port 46, and then enters the air guide duct 43, and is discharged from the front of the air guide duct 43. When the cooling airflow passes through the interior of the main stator body (through the channel formed by the ventilation port 46), it undergoes full and direct heat exchange with the high heat density silicon steel sheets, efficiently carrying away the heat generated inside the iron core of the main stator body. The heated air flowing out of the ventilation port at the front of the main stator body 44 will enter the air gap area between the main rotor 11 and the main stator 12, or mix with other cooling airflows in front. Finally, all the hot air is collected under the strong negative pressure suction generated by the cooling fan 6 and quickly discharged from the front cover 3, completing the entire cooling cycle.

[0088] Working principle of the invention:

[0089] I. Structural Layout and Space Compression Principle: The physical basis for achieving "flattening" is that the "flattening" of the generator is not a simple compression, but is achieved through a clever radial nesting and axial overlapping design.

[0090] Radial nested layout:

[0091] The diameter of the main rotor 11 is designed to be larger than that of the excitation rotor 13. This diameter difference allows the excitation stator 20 and the excitation rotor 13 to be "embedded" or "nested" in the radial space behind the main rotor 11, rather than arranged sequentially along the axial direction in a conventional design.

[0092] Axial compression: As a result, the axial distance between the main generator section and the excitation section is compressed to a very small distance that only needs to meet basic insulation and mechanical safety requirements. This is the most fundamental reason for the significant reduction in the axial length of the entire machine.

[0093] Axial overlapping design: The center of the heat dissipation fan blade 6 has a large cavity that completely encloses the coil winding at the front end of the main stator 12. This allows the heat dissipation component (fan blade) and the heat-generating component (stator winding) to overlap in the axial direction, rather than being arranged side by side, thus saving axial space.

[0094] II. Principle of High-Efficiency Cooling Circulation System: The core mechanism to ensure "high-efficiency heat dissipation" is to solve the heat dissipation challenges brought about by compact design. The generator constructs a three-dimensional cooling network consisting of a main air duct naturally formed by the large diameter difference, an auxiliary air duct integrated into the structure, and an optimized air inlet and outlet terminal.

[0095] Main air duct – “Straight axial through-draft”:

[0096] Formation: The large diameter difference between the main and excitation rotors naturally creates a wide, straight, and almost bendless annular axial channel between them.

[0097] Process: After the cooling air enters cleanly through the open frame of the rear end cover 8 and the filter screen of the rear cover 22, most of the airflow passes directly through this annular channel, directly and efficiently flushing the working air gap between the main stator 12 and the main rotor 11. The path is short, the resistance is small, and there are no eddies, forming a highly efficient "through wind" effect.

[0098] Auxiliary airflow duct – “Targeted Penetrating Cooling”:

[0099] Auxiliary air duct in the casing: The hollow stator fixing ribs 42 inside the main casing 36 form an air guide channel 43. After the airflow enters, it generates a negative pressure suction effect through the exhaust holes 60 on these ribs.

[0100] Stator internal air duct: This negative pressure is connected to the corresponding through-hole vent 46 on the main stator body 44 and its hollow ventilation frame 45, actively drawing out the hot air from the main stator body 44 to achieve cooling of the main stator body 44.

[0101] Excitation zone airflow guidance: The air guide holes 52 on the excitation stator 20 ensure that the airflow can pass smoothly through its structural area, both cooling itself and maintaining the unobstructed flow of the main air duct at this location.

[0102] Air intake and exhaust terminal optimization:

[0103] Low-resistance air intake: The spoke-style open design of the rear cover 8 provides a large area and low-resistance air intake.

[0104] High-efficiency air outlet: The connecting and fixing ribs 31 of the front cover 3 adopt a parallelogram cross section, with its short side parallel to the exhaust direction, reducing the air resistance at the outlet; the forward-inclined air guide vanes 26 on the air outlet cover 2 guide the exhaust hot air to the outer surface of the casing 1, which can more effectively prevent hot air from flowing back to the air inlet of the generator and affecting the cooling efficiency. At the same time, it helps to guide the airflow away from the generator near the body area as soon as possible, reducing the backflow or vortex of hot air near the air outlet, thereby helping to reduce the outlet resistance of the entire exhaust system.

[0105] Power cycle: The airflow in all the air ducts is ultimately driven by the cooling fan blades 6 that rotate rapidly with the main shaft 10, forming a continuous air-cooling cycle that is drawn in from the rear, heats the interior, and is discharged from the front.

[0106] III. Electromagnetic Energy Conversion and Brushless Excitation Principle: Stable Power Generation in a Compact Space Within an optimized physical structure, electromagnetic energy is stably converted according to the brushless excitation principle.

[0107] Main power generation circuit: The prime mover drives the main shaft 10 to rotate through the disc coupling 4, which in turn drives the main rotor 11. The excitation winding on the main rotor is supplied with DC current to generate a rotating magnetic field. This magnetic field cuts the three-phase armature winding of the main stator 12, inducing a three-phase AC electromotive force, which outputs electrical energy through the terminal block 19.

[0108] Brushless excitation circuit:

[0109] Excitation: The automatic voltage regulator 16 outputs a controllable DC current to the stationary excitation stator 20 winding based on the output voltage feedback, thereby generating a stationary magnetic field.

[0110] Power generation and rectification: The static magnetic field is cut by the armature winding on the coaxially rotating excitation rotor 13, inducing alternating current, which is then converted into direct current by the rotating rectifier bridge 14 on its back.

[0111] Energy transfer: The rectified DC power is supplied to the excitation winding of the main rotor 11 through the wires on the main shaft 10, thereby establishing the main magnetic field and completing the contactless (brushless) excitation energy transfer.

[0112] Voltage regulation: Throughout the process, the AVR continuously monitors the output voltage and stabilizes the voltage by rapidly adjusting the excitation current to cope with load changes.

[0113] IV. Principles of External Integration and Protection Systems: Safety, Reliability, and Maintainability.

[0114] Electrical Integration and Protection: The junction box 7 provides a dustproof and shockproof enclosed space for the terminal block 19 and the built-in automatic voltage regulator 16. Its modular design (removable top panel 18 and side panel 17) facilitates wiring and maintenance. The clearance hole 37 at the top of the main housing 36 allows for neat and short-path access of internal cables to the junction box.

[0115] Stable and safe structure: The housing 1 provides the main frame and mounting base 35. Lifting lug 1 34 on the front cover 3 and lifting lug 2 47 on the rear cover 8 ensure safe lifting. The exhaust grille 2 and the rear cover 22 prevent foreign objects from entering the rotating parts from the front and rear ends, respectively.

[0116] In summary, this invention employs a large-diameter differential rotor to achieve a radially nested layout, combined with an axially overlapping design where cooling fan blades encircle the stator windings, thus shortening the axial dimension and achieving a truly flattened overall structure. Based on the wide, straight, annular axial main air duct naturally formed by the large-diameter differential, combined with low-resistance inlet and outlet designs, a highly efficient "through-draft" cooling system is constructed. The airflow path is short, resistance is low, and there are no vortices, improving the basic heat dissipation efficiency. The "hollow fixed rib - through-hole ventilation" auxiliary cooling system guides airflow to carry away heat from the main stator body, resulting in a more uniform temperature distribution. The air guide hole design on the excitation stator ensures both its own cooling and the unobstructed flow of the main air duct through the excitation area, preventing airflow blockage. While achieving compactness, it also ensures structural strength, ease of installation, and ease of maintenance. This invention successfully achieves miniaturization, weight reduction, and optimization of overall manufacturing costs while ensuring power generation performance and operational reliability, making it particularly suitable for vehicle-mounted, marine, and portable power generation equipment with stringent installation space requirements.

[0117] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A flat, compact generator, comprising a front cover (3), a housing (1), a rear cover (8), and a rear cover (22) connected sequentially from front to back, characterized in that, The front cover (3) is provided with an air outlet mesh cover (2) on the outside. The upper part of the outer side of the housing (1) is provided with a wiring board (19) and a cable outlet box (7). The wiring board (19) is located inside the cable outlet box (7). An automatic voltage regulator (16) is provided on the inner side of the cable outlet box (7). The main stator (12) is fixed inside the housing (1). The front end of the rear cover (8) is provided with an excitation stator (20). The excitation stator (20) is located inside the housing (1) and behind the main stator (12). The rear cover (22) is set at the rear end of the rear cover (8). The bearing (21) is provided inside the rear cover (8). The main shaft (10) is fixed inside the inner ring of the bearing (21). The front end face of the main shaft (10) is sequentially set from back to front by locking screws (9). There are several closely fitted disc couplings (4) and a locking plate (5). The main shaft (10) is provided with a cooling fan (6), a main rotor (11) and an excitation rotor (13) from front to back. The cooling fan (6) is located inside the front cover (3). The main rotor (11) is located inside the main stator (12). The main rotor (11) is electromagnetically coupled to the main stator (12). The excitation rotor (13) is located inside the excitation stator (20). The excitation rotor (13) is electromagnetically coupled to the excitation stator (20). The rear end face of the excitation rotor (13) is provided with a rectifier bridge (14). The terminal block (19) is electrically connected to the main stator (12) and the excitation stator (20). The diameter of the main rotor (11) is larger than the diameter of the excitation rotor (13). The housing (1) includes a housing body (36). Two symmetrically arranged mounting bases (35) are fixed to the lower end of the housing body (36). Two symmetrically arranged clearance holes (37) are opened at the upper end of the housing body (36). A base (39) and four symmetrically arranged mounting plates (38) are fixed to the upper end of the housing body (36). The base (39) is located between the two clearance holes (37). A wiring board (19) is detachably mounted on the upper end of the base (39) by screws. The corresponding two mounting plates... (38) The front and rear sides of the clearance holes (37) are respectively located at the corresponding positions. The front side of the housing body (36) is fixed with the front flange (40) and the rear side of the housing body (36) is fixed with the rear flange (41). The interior of the housing body (36) is provided with several stator fixing ribs (42) evenly distributed in a circle. The interior of the stator fixing ribs (42) is hollow to form an air guide channel (43). Several exhaust holes (60) are opened on the stator fixing ribs (42). The length of the stator fixing ribs (42) is less than the length of the housing body (36). The main stator (12) includes a hollow ventilation frame (45), which is open at both ends. The hollow ventilation frame (45) is engaged with several stator fixing ribs (42). The main stator body (44) is provided inside the hollow ventilation frame (45). Several sets of circumferentially distributed ventilation holes (46) are opened on the hollow ventilation frame (45). Each set of ventilation holes (46) corresponds to the position of the stator fixing ribs (42), and the ventilation holes (46) are connected to the exhaust holes (60) at the corresponding positions. The main stator (12) includes a hollow ventilation frame (45), which is a hollow cylinder. The hollow ventilation frame (45) is engaged with several stator fixing ribs (42). The hollow ventilation frame (45) has a main stator body (44) inside. Several sets of circumferentially distributed and penetrating ventilation holes (46) are opened on the main stator body (44) and the hollow ventilation frame (45). The ventilation holes (46) of the main stator body (44) and the ventilation holes (46) of the hollow ventilation frame (45) are corresponding and connected. Each set of ventilation holes (46) corresponds to the position of the stator fixing ribs (42), and the ventilation holes (46) are connected to the exhaust holes (60) at the corresponding positions. The front cover (3) includes a front rear flange (30) and a front front cover flange (33). The front rear flange (30) is detachably connected to the front end of the front flange (40) of the housing. A number of circumferentially distributed connecting fixing ribs (31) are fixed between the front rear flange (30) and the front front cover flange (33). The cross-section of the connecting fixing ribs (31) is a parallelogram. The short side of the connecting fixing ribs (31) is parallel to the exhaust direction. A lifting lug (34) is fixed at the upper end between the front rear flange (30) and the front front cover flange (33). The inner sides of the front rear flange (30) and the front front cover flange (33) are provided with placement grooves (32). The two placement grooves (32) form a locking groove. The air outlet mesh cover (2) includes a mesh cover body (24), which is fitted into the mesh cover groove. The thickness of the mesh cover body (24) is equal to the depth of the placement groove (32). The mesh cover body (24) is cylindrical. A clearance hole (25) is provided on the mesh cover body (24). A lifting lug (34) extends out from the clearance hole (25). Several sets of circumferentially distributed air outlets (27) are provided on the mesh cover body (24). Several sets of circumferentially distributed forward-tilting air guides (26) are fixed on the outside of the mesh cover body (24). The number and position of the air guides (26) correspond to the air outlets (27). The air guides (26) are located in front of the corresponding air outlets (27). Both ends of the mesh cover body (24) are provided with locking plates (28) that are perpendicular to their centers. The two locking plates (28) are directly opposite each other and several locking screw pairs (29) are provided between them. The excitation stator (20) includes an excitation stator ring frame (49), which has several mounting through holes (53). The inner side of the excitation stator ring frame (49) is provided with several circumferentially distributed excitation stator seats (50) integrally formed therewith. Each excitation stator seat (50) and the excitation stator ring frame (49) are provided with a through air guide hole (52). The excitation stator seat (50) is provided with an excitation winding (51).

2. A flat, compact generator according to claim 1, characterized in that, The heat dissipation fan (6) includes a frustum-shaped impeller (66). An integrally formed flat key (64) is provided inside the mounting hole of the impeller (66). The mounting hole of the impeller (66) and the integral flat key (64) are fitted together and installed on the main shaft (10). The rear end face of the impeller (66) is provided with several circumferentially distributed L-shaped blades (61). The front end face of the blades (61) is provided with a reinforcing ring (63). The rear end face of the blades (61) is provided with a reinforcing base plate (62). The front end face of the impeller (66) is provided with several circumferentially distributed reinforcing ribs (65).

3. A flat, compact generator according to claim 2, characterized in that, The rear end cover (8) includes a rear end cover body (55), with a lifting lug (47) fixed to the upper end of the rear end cover body (55). The rear end cover body (55) has several circumferentially distributed mounting through holes (56). The rear end cover body (55) is detachably mounted at the rear end of the rear flange (41) of the housing by passing through the corresponding mounting through holes (56) with several mounting bolts (54). The middle part of the rear end cover body (55) is provided with a bearing seat (58) through four supporting ribs. The bearing (21) is located at the rear end of the housing. Inside the bearing housing (58), the front end of the rear cover body (55) is provided with four symmetrically arranged connecting seats (48), each of which is provided with mounting screw holes (57). The rear end of the rear cover body (55) is provided with a placement groove, and the rear cover (22) is detachably installed inside the placement groove. The thickness of the rear cover (22) is equal to the depth of the placement groove. Several rear cover filters (23) are provided on the front side of the rear cover (22), and the rear cover filters (23) extend into the interior of the rear cover body (55).

4. A flat, compact generator according to claim 3, characterized in that, The number and position of the mounting through hole (53) correspond to the mounting screw hole (57). The mounting through hole (53) and the corresponding mounting screw hole (57) are connected by connecting bolts. The difference between the diameter of the main rotor (11) and the diameter of the excitation rotor (13) is greater than or equal to 150mm.

5. A flat, compact generator according to claim 4, characterized in that, The outlet box (7) includes two end plates (15) arranged symmetrically front and back. The end plates (15) are fixed to the outside of two mounting plates (38) on the same side. The lower end of the end plate (15) is provided with an arc-shaped notch that fits tightly against the main body (36) of the casing. The left and right sides of the two end plates (15) are provided with side plates (17) by screws. The upper ends of the two end plates (15) and the two side plates (17) are provided with a top plate (18) by screws. The automatic voltage regulator (16) is provided with screws on the inside of one of the side plates (17).

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