RV speed reduction driving assembly driven by axial magnetic flux motor

Abstract

The invention provides an axial magnetic flux motor driven RV speed reduction driving assembly which comprises an axial magnetic flux motor unit and an RV speed reducer unit which are connected, the axial magnetic flux motor unit and the RV speed reducer unit are integrated in a shell, the axial magnetic flux motor unit comprises a plurality of stators which are distributed in an annular mode, and the stators are connected with the axial magnetic flux motor unit. A stator is arranged on the rotor, a disc type rotor is arranged on each of the two sides of the stator, a plurality of torsion bars which are uniformly distributed in the circumferential direction are arranged on the rotor facing the side where the RV speed reducer unit is located, the torsion bars are connected with a sun gear of a planetary gear train of the RV speed reducer unit, and an output disc of the RV speed reducer unit is a power output end. The RV speed reduction driving assembly driven by the axial magnetic flux motor has the advantages of being large in starting torque, high in mechanical efficiency, compact in structure, high in overload capacity and the like.

Description

Technical Field

[0001] This invention relates to the field of transmission technology, and in particular to an RV reduction drive assembly driven by an axial flux motor. Background Technology

[0002] Driven by breakthroughs and widespread applications in key technologies such as new energy batteries, motors, and electronic control systems, the field of non-road new energy vehicles, including logistics handling vehicles, intelligent AGVs, and aerial work platforms, has experienced rapid development. These engineering vehicles typically switch frequently between loaded and unloaded states during operation: under load, the vehicle weight increases significantly, requiring tasks such as moving, transferring, or lifting heavy objects; while under unload, the vehicle needs to quickly move to the next work location to reduce ineffective work time and improve overall operational efficiency. The functional characteristics of the vehicle determine a significant difference in its curb weight between loaded and unloaded states, thus placing clear dual requirements on the undercarriage drive system—it needs to output low-speed, high torque under load conditions to meet load-bearing and operational needs; under unload conditions, it needs to have high-speed, low-torque output capabilities to achieve rapid site relocation.

[0003] Currently, the mainstream solutions for achieving off-vehicle walking drive in the industry mostly adopt a drive assembly combining a permanent magnet synchronous motor and a planetary gear reducer. Although this structure has a certain degree of technological maturity, it still has several key defects in practical applications, which restrict the optimization of overall machine performance and structural layout: First, the power density of this drive assembly is low. Because the permanent magnet synchronous motor and the planetary reduction gear are separate components, the system integration is limited, and the power output per unit volume or unit mass is insufficient, making it difficult to meet the needs of off-road vehicles for a compact and efficient power system.

[0004] Secondly, permanent magnet synchronous motors have a relatively long axial dimension, occupying a large amount of space. In the overall vehicle layout, especially in the chassis of engineering machinery or special vehicles where installation space is strictly limited, an excessively long motor size will significantly affect the layout of other components, increasing the difficulty and complexity of the overall vehicle design.

[0005] Third, to achieve a larger transmission ratio, planetary reducers often require a multi-stage transmission structure, which directly leads to a significant increase in their axial dimension. For engineering vehicles with limited installation space and high requirements for structural compactness, an excessively large axial dimension restricts the overall structural design and affects the vehicle's passability and maneuverability in narrow or complex working conditions. Summary of the Invention

[0006] The present invention aims to solve the above-mentioned technical problems by providing an RV reduction drive assembly driven by an axial flux motor.

[0007] The technical solution of the present invention is an RV reduction drive assembly driven by an axial flux motor, comprising an axial flux motor unit and an RV reducer unit connected together. The axial flux motor unit and the RV reducer unit are integrated into a housing. The axial flux motor unit includes several stators arranged in a ring. A disc rotor is provided on each side of the stator. Several torsion bars are evenly distributed circumferentially on the rotor facing the side where the RV reducer unit is located. The torsion bars are connected to the sun gear of the planetary gear train of the RV reducer unit. The output disc of the RV reducer unit is the power output end.

[0008] In one embodiment, the housing is provided with an axial spiral flow channel that surrounds the outer edge of the stator and is in close contact with the outer contour of the stator. A radial micro-channel is provided between adjacent stators that is in close contact with the sidewall of the stator. One end of the radial micro-channel converges to the inlet channel, which is connected to the axial spiral flow channel. The other end of the radial micro-channel converges to the outlet channel. A stator bushing is provided in the area enclosed by several stators. The stator bushing is made of a high thermal conductivity material. One end of the stator bushing is in contact with the stator, and the other end is in contact with the torsion bar through a heat-conducting pin. The torsion bar is a temperature-sensitive elastic alloy bar that has undergone heat treatment. When the temperature of the torsion bar exceeds a preset value, the shear strength of the torsion bar decreases significantly.

[0009] In one embodiment, the stator windings are embedded in a stator core encapsulated by a highly thermally conductive insulating material.

[0010] In one implementation, the two rotors are fixed on the same rotor hub.

[0011] In one embodiment, the planetary gear train of the RV reducer unit further includes three planetary gears, which mesh with the sun gear; The RV reducer unit includes a crankshaft that rotates synchronously with the planetary gears. The crankshaft has an eccentric portion. The RV reducer unit also includes a cycloidal wheel that rotates with the eccentric portion and a number of pin teeth that mesh with the cycloidal wheel. The number of teeth on the cycloidal wheel is less than the number of pin teeth.

[0012] In one embodiment, the rotor includes a turntable on which a plurality of permanent magnets are spaced apart along its circumference. The magnetization direction of the permanent magnets is axial, and the magnetization directions of adjacent permanent magnets are opposite, so as to form alternating N poles and S poles on the surface of the turntable.

[0013] In one embodiment, the permanent magnet is a tile-shaped magnet.

[0014] In one embodiment, the rotor further includes a pressure plate, which is annular and presses and fixes the turntable axially from both sides of the turntable.

[0015] In one embodiment, the pressure plate is made of a non-magnetic material.

[0016] In one embodiment, one end of the axial spiral flow channel is connected to the inlet, and one end of the outlet flow channel is connected to the outlet. The cooling medium circuit where the inlet and outlet are located is equipped with a speed-adjustable cooling pump. A temperature sensor is provided on the stator bushing, and a thermal switch is provided between the stator bushing and the heat-conducting pin. The cooling pump, the temperature sensor, and the thermal switch are all connected to a controller. The base of the thermal switch is fixedly connected to the heat-conducting pin. The moving contact of the thermal switch is a heat-conducting contact that can move linearly. In the default state, the moving contact is separated from the stator bushing under the action of the spring to form a thermal isolation gap. When the electromagnetic actuator of the thermal switch receives the control signal from the controller, it drives the moving contact to overcome the spring force and press tightly against the stator bushing. When the temperature value detected by the temperature sensor is less than the first threshold, the cooling pump operates at the base speed; when the temperature value detected by the temperature sensor is greater than the first threshold and less than the second threshold, the cooling pump accelerates; when the temperature value detected by the temperature sensor is greater than the second threshold, the controller sends a control signal to the thermal switch to connect the heat conduction path between the stator bushing and the heat-conducting pin.

[0017] The advantages of this invention compared to the prior art are: 1. Axial flux motors have high power density, large starting torque, and higher mechanical efficiency than permanent magnet synchronous motors; 2. The RV reducer transmission has a compact structure, strong overload capacity, and high reduction transmission accuracy, reaching arc minute accuracy. The reduction transmission ratio of the same size is greater than that of the planetary reducer. 3. Axial flux motors, when used with a motor controller, can achieve stepless speed regulation; IV. When high-power transmission is required, an oil-cooled or water-cooled flow channel can be added inside the axial flux motor to meet the high-power continuous operation requirements of engineering machinery. 5. The axial flux motor can be easily integrated with an electromagnetic brake that has deceleration and braking functions. The motor control works in conjunction with the back electromotive force of the axial flux motor, resulting in excellent braking performance. Attached Figure Description

[0018] Figure 1 A first structural schematic diagram of an RV reduction drive assembly driven by an axial flux motor provided for an embodiment of the present invention; Figure 2A second structural schematic diagram of an RV reduction drive assembly driven by an axial flux motor provided in an embodiment of the present invention; Figure 3 for Figure 1 A partially enlarged view of the RV reduction drive assembly driven by the axial flux motor provided in the image; Figure 4 A partial enlarged view of the thermal switch provided for an embodiment of the present invention.

[0019] In the diagram: 1. Axial flux motor unit; 2. RV reducer unit; 3. Housing; 4. Stator; 5. Rotor; 6. Torsion bar; 7. Sun gear; 8. Output disc; 9. Axial helical flow channel; 10. Radial micro-flow channel; 11. Inlet flow channel; 12. Outlet flow channel; 13. Stator bushing; 14. Heat-conducting pin; 15. Planetary gear; 16. Crankshaft; 17. Cycloidal wheel; 18. Needle tooth; 19. Turntable; 20. Permanent magnet; 21. Pressure plate; 22. Heat dissipation hole; 23. Thermal switch; 24. Base; 25. Moving contact; 26. Thermal isolation gap. Detailed Implementation

[0020] The above and other embodiments and advantages of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] In one implementation, such as Figure 1 As shown.

[0022] The RV reduction drive assembly driven by the axial flux motor provided in this embodiment includes an axial flux motor unit 1 and an RV reducer unit 2 connected together. The axial flux motor unit 1 and the RV reducer unit 2 are integrated in a housing 3. The axial flux motor unit 1 includes a plurality of stators 4 arranged in a ring. A disc rotor 5 is provided on each side of the stator 4. A plurality of torsion bars 6 are evenly distributed in the circumference on the rotor 5 facing the side where the RV reducer unit 2 is located. The torsion bars 6 are connected to the sun gear 7 of the planetary gear train of the RV reducer unit 2. The output disc 8 of the RV reducer unit 2 is the power output end.

[0023] In this embodiment, the drive assembly using a combination of a permanent magnet synchronous motor and a planetary reducer, as mentioned in the background art, addresses the issue of performance and structural layout optimization limitations. This RV reduction drive assembly driven by an axial flux motor effectively shortens the axial dimension due to the flattened structure of the axial flux motor, and its dual-rotor design improves power density. To address the problem of excessive axial length in the reduction mechanism, the RV reducer, with its single-stage large transmission ratio characteristic, can replace the multi-stage planetary reduction structure. By integrating the two units into the same housing 3, the wasted connection space of the split structure is eliminated. The key point is the direct power transmission path between the rotor 5 and the reducer, avoiding the axial extension caused by traditional couplings. Therefore, the drive assembly proposed in this embodiment includes a connected axial flux motor unit 1 and an RV reducer unit 2, both integrated within the housing 3. The axial flux motor unit 1 includes several stators 4 arranged in a ring. Disc rotors 5 are arranged on both sides of the stators 4. Torque bars 6 are evenly distributed in the circumference on the rotors 5 facing the reducer side. These torsion bars 6 are connected to the sun gear 7 of the planetary gear train of the RV reducer. The reducer output disc 8 serves as the power output end.

[0024] The axial flux motor unit 1 is an electromagnetic energy conversion device with the magnetic field direction parallel to the motor axis. Specifically, it can be implemented using a symmetrical structure with a dual-rotor clamping the stator. This structure generates a rotating magnetic field through annularly distributed stator windings, and the synchronous rotation of the two rotating disks 19 generates torque. The disc rotor 5 is a disc-shaped rotating component extending axially, specifically implemented using a metal disc with an array of permanent magnets 20. Its symmetrical arrangement balances the axial magnetic pull. The circumferentially evenly distributed torsion bars 6 are elastic transmission components arranged at equal angles along the circumference. Specifically, they can be implemented using columnar rods made of alloy steel, with both ends connected to the rotating disks 19 and the sun gear shaft, respectively, to achieve torque transmission and overload protection. The axial flux motor unit 1 generates high power density torque through the dual-rotor structure. When the rotor 5 rotates, it drives the circumferentially distributed torsion bars 6 to rotate synchronously. The torsion bars 6 directly transmit power to the sun gear shaft of the RV reducer, driving the planetary gear train for initial reduction. The reduced power is transmitted to the cycloidal gear train via crankshaft 16 to complete the two-stage reduction, and finally output at low speed with high torque by output disc 8. The integrated housing 3 serves as both the closing component of the motor magnetic circuit and the support structure of the reducer, eliminating the redundant space of traditional split housings. The symmetrical layout of the disc rotor 5 counteracts axial magnetic attraction and reduces bearing load, while the elastic deformation of the torsion bar 6 can buffer impact loads.

[0025] Compared to drive assemblies that combine permanent magnet synchronous motors and planetary gearboxes, this RV reduction drive assembly driven by an axial flux motor shortens the motor section length through the axial flux motor, and the RV reducer achieves the transmission ratio of a traditional three-stage planetary reduction in a single stage, resulting in a significant reduction in overall axial dimensions. The integrated design combines the motor yoke and the reducer housing into one unit, reducing structural weight.

[0026] Through the above technical solutions, this application effectively improves the power density of the powertrain system, resulting in a smaller volume for the same output power. The shortened axial length allows for more flexible vehicle chassis layout, adapting to installation requirements in confined spaces. The integrated structure reduces the number of components and improves system reliability. The direct drive path reduces energy loss and improves transmission efficiency. Under overload, the torsion bar 6 can undergo elastic deformation to prevent mechanical damage, extending its service life compared to rigid couplings.

[0027] In one implementation, such as Figures 1 to 3 As shown.

[0028] The RV reduction drive assembly driven by the axial flux motor provided in this embodiment has an axial helical flow channel 9 inside its housing 3. The axial helical flow channel 9 surrounds the outer edge of the stator 4 and is in close contact with the outer contour of the stator 4. A radial micro-flow channel 10 is provided between adjacent stators 4. The radial micro-flow channel 10 is in close contact with the side wall of the stator 4. One end of the radial micro-flow channel 10 converges to the inlet flow channel 11, which is connected to the axial helical flow channel 9. The other end of the radial micro-flow channel 10 converges to the outlet flow channel 12. A stator bushing 13 is provided in the area enclosed by several stators 4. The stator bushing 13 is made of a high thermal conductivity material. One end of the stator bushing 13 contacts the stator 4, and the other end contacts the torsion bar 6 through a heat-conducting pin 14. The torsion bar 6 is a temperature-sensitive elastic alloy bar that has undergone heat treatment. When the temperature of the torsion bar 6 exceeds a preset value, the shear strength of the torsion bar 6 decreases significantly.

[0029] In this embodiment, the axial flux motor-driven RV reduction drive assembly has an axial spiral flow channel 9, which refers to a spiral cooling medium channel extending axially along the housing 3. Specifically, it can be implemented using a combination of annular grooves and spiral guide vanes surrounding the outer edge of the stator 4, extending the contact time between the cooling medium and the outer surface of the stator 4 through the spiral path. The radial micro-channel 10 refers to the tiny flow gap between adjacent stator 4 sidewalls, specifically implemented by machining grooves with a depth of 0.5-1mm on the side of the stator core, forming a densely distributed heat dissipation channel network. The stator bushing 13 refers to an annular heat-conducting component located within the enclosed area of ​​the stator 4, specifically implemented using a copper-aluminum alloy casting, with its outer surface maintaining close contact with the stator core end face. The heat-conducting pin 14 refers to the heat transfer component connecting the stator bushing 13 and the torsion bar 6, specifically implemented using a nickel-plated copper cylindrical pin, ensuring the continuity of the axial heat conduction path. Temperature-sensitive elastic alloy rods refer to transmission components with temperature-strength response characteristics. Specifically, they can be made from nickel-titanium-based shape memory alloys through a graded aging heat treatment process, resulting in a shear strength reduction of more than 50% within a temperature range of 80-100℃.

[0030] In this embodiment, the cooling medium flows axially spirally along the outer edge of the stator 4 through the axial spiral flow channel 9, carrying away heat from the stator winding ends and the outer surface of the core. It then flows through the inlet flow channel 11 to the radial micro-channels 10, flowing radially along the sidewalls of the stator 4 to cool the internal area of ​​the core, and finally exits through the outlet flow channel 12. The heat generated during stator 4 operation is conducted through the core to the stator bushing 13, and then transferred to the root of the torsion bar 6 via the heat-conducting pin 14. When the system operates under continuous overload, causing an abnormal temperature rise, heat rapidly accumulates along this conduction path to the torsion bar 6. When the temperature reaches the material phase transformation critical point, the shear strength of the torsion bar 6 actively decreases until it breaks, thus cutting off the power transmission path. Traditional solutions relying solely on the surface of the motor housing for heat dissipation cannot effectively remove heat from the interior of the stator 4 and the winding area. Compared to traditional solutions, this embodiment forms a three-dimensional heat dissipation network through the axial spiral flow channel 9 and the radial micro-channels 10, allowing the cooling medium to directly contact the outer surface of the stator 4 and the gaps between adjacent cores, significantly improving heat dissipation efficiency. At the same time, a directional heat conduction path is established from stator 4 to torsion bar 6. Combined with the characteristics of temperature-sensitive materials, active mechanical protection is achieved when the transmission system overheats, avoiding component damage caused by the response delay of temperature sensors in traditional solutions.

[0031] In this embodiment, the problem of heat accumulation inside the drive assembly caused by shortening the wheelbase and increasing power density is effectively solved. Specifically, heat in the stator 4 area is quickly dissipated through a three-dimensional heat dissipation network, reducing the operating temperature of critical transmission components. When an abnormal temperature rise occurs, the heat conduction path directs the heat to the torsion bar 6, triggering its strength abrupt change characteristics to cut off power, thus completing system protection before reaching the mechanical overload torque.

[0032] In one implementation, such as Figure 1 As shown.

[0033] The RV reduction drive assembly driven by the axial flux motor provided in this embodiment has its stator 4 winding embedded in a stator core encapsulated by a high thermal conductivity insulating material.

[0034] In this embodiment, the high thermal conductivity insulating material in the RV reduction drive assembly driven by the axial flux motor refers to a non-metallic composite material with high thermal conductivity and meeting electrical insulation requirements. Specifically, it can be epoxy resin filled with aluminum nitride ceramic or alumina ceramic. This type of material ensures the insulation performance between the winding and the core while forming an efficient heat conduction path. The stator core encapsulation structure refers to completely embedding the winding into the core slot and filling it with high thermal conductivity insulating material through a molding process. Specifically, it can be achieved using a vacuum pressure impregnation process. This structure makes the winding and the core form an integrated heat conductor, eliminating the air gap between the winding and the core in the traditional way. The winding is completely wrapped in the core slot, and the high thermal conductivity insulating material fills the gap between the winding and the core, forming a continuous thermal interface. Heat is conducted to the core surface through the insulating material, and then heat exchange is achieved through the contact between the core and the external heat dissipation structure. The heat generated by the winding does not need to rely on air convection and is directly discharged through the solid material conduction path, avoiding local temperature accumulation. The iron core packaging structure remains flat in the axial direction, eliminating the need for additional heat sinks or air ducts, thus maintaining the overall compact size of stator 4.

[0035] In this embodiment, a high thermal conductivity material is used instead of the conventional insulating medium to rapidly conduct heat from the windings to the core, allowing the windings to operate at higher current densities. Simultaneously, the encapsulation structure eliminates the traditional winding end protrusions, reducing axial space occupation. Through this technical solution, heat from the stator windings is directly conducted to the core via the high thermal conductivity insulating material, avoiding power limitations caused by excessive winding temperature rise and increasing motor power density. The encapsulation structure reduces the axial dimensions of the stator, adapting to compact space layout requirements; the insulating properties of the high thermal conductivity material ensure reliable electrical isolation between the windings and the core, avoiding short-circuit risks.

[0036] In one embodiment, the two rotors 5 of the RV reduction drive assembly driven by the axial flux motor are fixed on the same rotor hub.

[0037] In this embodiment, the rotor hub refers to the central support structure used to fix the two rotors 5. Specifically, it can be made of high-strength aluminum alloy material through precision casting or machining, and its interior has a keyway or spline structure that mates with the motor shaft. This structure serves as a common mounting reference for the two rotors, eliminating the cumulative error of axial clearance during independent installation. In the axial flux motor unit 1, the two disc rotors 5 are symmetrically fixed to the left and right end faces of the rotor hub by bolts or welding. The rotor hub and the motor output shaft are connected by an interference fit or a key to achieve synchronous rotation, making the two rotors 5 form a rigid whole. Since the two rotors share the same support structure, there is no need to set up separate mounting flanges and positioning mechanisms for each rotor 5, thereby reducing the axial space occupied. At the same time, the symmetrical design of the rotor hub ensures that the magnetic pole distribution of the two rotors 5 remains strictly coaxial, avoiding magnetic field asymmetry caused by assembly deviations.

[0038] In one implementation, such as Figure 2 As shown.

[0039] The RV reduction drive assembly driven by the axial flux motor provided in this embodiment includes a planetary gear system with three planetary gears 15 meshing with the sun gear 7; the RV reducer unit 2 includes a crankshaft 16 that rotates synchronously with the planetary gears 15, the crankshaft 16 having an eccentric part, the RV reducer unit 2 also includes a cycloidal wheel 17 that rotates in coordination with the eccentric part and a plurality of pin teeth 18 that mesh with the cycloidal wheel 17, the number of teeth of the cycloidal wheel 17 being less than the number of pin teeth 18.

[0040] In this embodiment, planetary gear 15 refers to a gear that revolves around and meshes with the sun gear 7. Specifically, it can be implemented using planetary gears with involute teeth, used to transmit the rotational motion of the sun gear 7 to the crankshaft 16. The crankshaft 16 refers to a shaft that rotates synchronously with the planetary gear 15. Specifically, it can be implemented using a one-piece shaft structure made of medium carbon alloy steel, used to convert the revolution of the planetary gear 15 into eccentric rotational motion. The eccentric portion refers to a cylindrical protrusion on the crankshaft 16 that is off-center from the axis. Specifically, it can be implemented by machining to form an eccentric geometry, used to drive the cycloidal wheel 17 to produce eccentric oscillation. The cycloidal wheel 17 refers to a disc-shaped gear with cycloidal teeth, specifically made of high-hardness bearing steel through a heat treatment process, used to mesh with fixed pin teeth 18 to achieve speed reduction. The pin teeth 18 refer to cylindrical pins evenly distributed along the circumference, specifically made of alloy steel pins with nitrided surface treatment, used to form a meshing pair with the cycloidal wheel 17. The sun gear 7 drives three planetary gears 15 to revolve around it through meshing. The planetary gears 15 drive the crankshaft 16 to rotate synchronously. The eccentric part of the crankshaft 16 forces the cycloidal wheel 17 to perform an eccentric rotational motion around its own axis. During the eccentric motion, the teeth of the cycloidal wheel 17 continuously mesh with the fixed pin teeth 18. Since the number of teeth of the cycloidal wheel 17 is less than the number of pin teeth 18, the cycloidal wheel 17 lags behind the pin teeth 18 by a fixed angle after each eccentric rotation, thus forming a reduction ratio. The two-stage reduction structure of the planetary gear train and the cycloidal transmission is integrated on the same axis. The planetary gear train achieves the first-stage reduction and distributes the load, while the cycloidal transmission achieves a large second-stage reduction ratio through tooth difference design, avoiding the axial superposition caused by the traditional multi-stage planetary gear series connection.

[0041] In one implementation, such as Figure 3 As shown.

[0042] The RV reduction drive assembly driven by the axial flux motor provided in this embodiment has a rotor 5 including a turntable 19. The turntable 19 is provided with a plurality of permanent magnets 20 spaced circumferentially on it. The magnetization direction of the permanent magnets 20 is axial, and the magnetization directions of adjacent permanent magnets 20 are opposite, so as to form alternating N poles and S poles on the surface of the turntable 19. Preferably, the permanent magnets 20 are tile-shaped magnets.

[0043] In this embodiment, the turntable 19 refers to the annular metal substrate that supports the permanent magnets 20. Specifically, it can be made of aluminum alloy or low-carbon steel and serves as a rigid support structure for mounting the permanent magnets 20. The regular arrangement of magnetic poles is achieved through circumferential spacing. The permanent magnets 20 are magnetic elements with axial magnetization characteristics, specifically made of neodymium iron boron or samarium cobalt. The axial magnetization direction is set so that the magnetic field direction is consistent with the motor axis, forming effective magnetic coupling with the stator windings. Opposite magnetization directions mean that the magnetization directions of adjacent permanent magnets 20 are opposite in the axial direction. This can be achieved through directional magnetization using a magnetization mold, resulting in a continuous alternating distribution of N and S poles on the surface of the turntable 19, reducing magnetic leakage areas between poles. The turntable 19, as the mounting carrier for the permanent magnets 20, improves the uniformity of the magnetic field distribution by optimizing the pole spacing through its circumferentially spaced permanent magnet layout. The axial magnetization direction extends the magnetic field path along the motor axis, forming a magnetic flux loop perpendicular to the stator windings, thus shortening the magnetic path length compared to traditional radial magnetization. The design of adjacent permanent magnets 20 with opposite magnetization directions creates alternating N and S poles on the surface of the turntable 19. This alternating polarity generates a magnetic field gradient that enhances the effective magnetic field strength while eliminating magnetic flux leakage caused by continuous distribution of a single pole. This layout, while maintaining the number of poles, achieves an equivalent increase in pole density through alternating polarity, thereby achieving higher magnetic field utilization within a limited axial space.

[0044] In this embodiment, the tile-shaped magnet refers to a magnet structure with an arc-shaped cross-section. Specifically, it can be made by processing sintered NdFeB material through a curved surface forming process, and its arc-shaped surface matches the circumferential curvature of the turntable 19. This structure, through geometric adaptation, enables the magnet to form surface contact with the surface of the turntable 19, reducing the increase in magnetic resistance caused by assembly gaps.

[0045] In one embodiment, the rotor 5 of the RV reduction drive assembly driven by the axial flux motor further includes a pressure plate 21, which is annular and presses and fixes the turntable 19 axially from both sides of the turntable 19.

[0046] In this embodiment, the pressure plate 21 refers to an annular structural component used to apply axial pressure from both sides of the turntable 19 for fixation. Specifically, it can be a ring-shaped plate made of metal or composite material, suppressing vibration of the turntable 19 through symmetrical clamping. The turntable 19 refers to the rotating component that mounts the permanent magnets 20. Specifically, it can be a disc with circumferentially spaced mounting slots for the permanent magnets 20, fixed by the pressure plate 21 to prevent displacement of the permanent magnets 20. The pressure plate 21 covers the entire circumferential area on both sides of the turntable 19, locking the turntable 19 and the permanent magnets 20 together through axial clamping force. The annular pressure plate 21 distributes pressure evenly, avoiding localized stress concentration. The contact surface between the pressure plate 21 and the turntable 19 is planar, ensuring uniform pressure transmission. During high-speed rotation, the symmetrical constraint of the pressure plate 21 counteracts the deformation of the turntable 19 caused by centrifugal force, maintaining the stable position of the permanent magnets 20. The axial fixing method eliminates the need for radially additional connecting structures on the turntable 19, reducing the overall axial dimension of the rotor 5.

[0047] In one embodiment, the pressure plate 21 of the RV reduction drive assembly driven by the axial flux motor is made of a non-magnetic material.

[0048] In this embodiment, non-magnetic material refers to material with magnetic permeability close to vacuum and does not participate in magnetic circuit conduction. Specifically, it can be made of aluminum alloy, austenitic stainless steel or titanium alloy. Its low magnetic permeability can block the propagation path of magnetic field in pressure plate 21.

[0049] In one embodiment, the turntable 19 of the RV reduction drive assembly driven by the axial flux motor is also provided with a plurality of heat dissipation holes 22 distributed at intervals along its circumference.

[0050] In this embodiment, the circumferential spacing distribution refers to the non-continuous arrangement of the heat dissipation holes 22 around the circumference of the turntable 19. Specifically, it can be achieved by using hole layouts with equal or unequal angular intervals. This distribution ensures that the heat dissipation area on the surface of the turntable 19 is uniformly covered. The heat dissipation holes 22 are through-hole structures that penetrate the thickness of the turntable 19. Specifically, they can be circular, elliptical, or polygonal in shape. The hole structure promotes heat exchange by increasing the contact area between the turntable 19 and the airflow.

[0051] In one implementation, such as Figures 1 to 4 As shown.

[0052] The RV reduction drive assembly driven by the axial flux motor provided in this embodiment has an axial spiral flow channel 9 inside the housing 3. The axial spiral flow channel 9 surrounds the outer edge of the stator 4 and is close to the outer contour of the stator 4. A radial micro-flow channel 10 is provided between adjacent stators 4. The radial micro-flow channel 10 is close to the side wall of the stator 4. One end of the radial micro-flow channel 10 converges to the inlet flow channel 11, which is connected to the axial spiral flow channel 9. The other end of the radial micro-flow channel 10 converges to the outlet flow channel 12. A stator bushing 13 is provided in the area enclosed by several stators 4. The stator bushing 13 is made of a high thermal conductivity material. One end of the stator bushing 13 contacts the stator 4, and the other end contacts the torsion bar 6 through a heat-conducting pin 14. The torsion bar 6 is a temperature-sensitive elastic alloy bar that has undergone heat treatment. When the temperature of the torsion bar 6 exceeds a preset value, the shear strength of the torsion bar 6 decreases significantly. One end of the axial spiral flow channel 9 is connected to the inlet, and one end of the outlet flow channel 12 is connected to the outlet. The cooling medium circuit where the inlet and outlet are located is equipped with a speed-adjustable cooling pump. The stator bushing 13 is equipped with a temperature sensor. A thermal switch 23 is provided between the stator bushing 13 and the heat-conducting pin 14. The cooling pump, the temperature sensor and the thermal switch 23 are all connected to the controller. The base 24 of the thermal switch 23 is fixedly connected to the heat-conducting pin 14. The moving contact 25 of the thermal switch 23 is a heat-conducting contact that can move linearly. In the default state, the moving contact 25 is separated from the stator bushing 13 under the action of the spring, forming a thermal isolation gap 26. When the electromagnetic actuator of the thermal switch 23 receives the control signal from the controller, it drives the moving contact 25 to overcome the spring force and press tightly against the stator bushing 13. When the temperature value detected by the temperature sensor is less than the first threshold, the cooling pump runs at the base speed; when the temperature value detected by the temperature sensor is greater than the first threshold but less than the second threshold, the cooling pump runs at a higher speed; when the temperature value detected by the temperature sensor is greater than the second threshold, the controller sends a control signal to the thermal switch 23 to connect the heat conduction path between the stator bushing 13 and the heat-conducting pin 14.

[0053] In this embodiment, the thermal switch 23 refers to a device that controls the opening and closing of the heat conduction path through electromagnetic actuation. Specifically, it can be implemented using a separable thermally conductive contact structure driven by an electromagnetic coil. Its function is to actively adjust the heat transfer efficiency between the stator 4 and the torsion bar 6 according to temperature changes. The temperature sensor refers to a detection element used to monitor the temperature of the stator bushing 13. Specifically, it can be implemented using a surface-mount thermocouple or a thin-film resistance temperature sensor. Its function is to provide real-time temperature data for cooling pump speed regulation and thermal switch 23 operation. When the temperature sensor detects that the temperature of the stator bushing 13 is lower than the first threshold, the controller maintains the cooling pump at the base speed, at which time the cooling medium flow rate meets the normal heat dissipation requirements. When the temperature rises to between the first and second thresholds, the controller increases the cooling pump speed and increases the cooling medium flow rate to enhance heat dissipation capacity. When the temperature exceeds the second threshold, the controller triggers the electromagnetic actuator to drive the moving contact 25 of the thermal switch 23 to press against the base 24, opening the heat conduction path between the stator bushing 13 and the heat-conducting pin 14, allowing heat to be transferred to the torsion bar 6 for dissipation through the heat-conducting pin 14.

[0054] This embodiment uses a temperature sensor to monitor in real time and link with the controller to achieve gradient adjustment of the cooling pump speed. Combined with the intelligent control of the heat conduction path by the thermal switch 23, a multi-level temperature response mechanism is formed. Compared to conventional methods that use fixed flow channels for unidirectional heat dissipation, this embodiment uses a combination design of axial spiral flow channel 9 and radial micro-channel flow channel 10 to form a three-dimensional heat dissipation network on the outer edge and gap area of ​​the stator 4, significantly improving heat dissipation area and efficiency. Furthermore, the cooling medium flow rate is dynamically adjusted according to the actual temperature of the drive assembly, maintaining low energy consumption under normal operating conditions and rapidly enhancing heat dissipation capacity under high-temperature conditions. Through the active control of the thermal switch 23, additional heat dissipation paths are established under extreme temperature conditions, preventing magnetic performance degradation caused by stator 4 overheating. The synergistic effect of the axial spiral flow channel 9 and radial micro-channel flow channel 10 ensures that the cooling medium covers the outer surface and gap area of ​​the stator 4, eliminating local hot spots. The graded temperature response mechanism balances heat dissipation efficiency and energy consumption control, solving the problem of fluctuating heat dissipation demand caused by frequent load switching of off-road vehicles and extending the service life of the drive system.

[0055] The specific embodiments described above further illustrate the inventive purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, or improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An RV reduction drive assembly driven by an axial flux motor, characterized in that, The device includes an axial flux motor unit and an RV reducer unit connected together, with the axial flux motor unit and the RV reducer unit integrated into a housing. The axial flux motor unit includes several stators arranged in a ring, and a disc rotor is provided on each side of the stator. Several torsion bars are evenly distributed circumferentially on the rotor facing the RV reducer unit. The torsion bars are connected to the sun gear of the planetary gear train of the RV reducer unit. The output disc of the RV reducer unit is the power output end.

2. The RV reduction drive assembly driven by an axial flux motor according to claim 1, characterized in that, The housing is provided with an axial spiral flow channel that surrounds the outer edge of the stator and is in close contact with the outer contour of the stator. A radial micro-flow channel is provided between adjacent stators that is in close contact with the side wall of the stator. One end of the radial micro-flow channel converges to the inlet flow channel, which is connected to the axial spiral flow channel. The other end of the radial micro-flow channel converges to the outlet flow channel. A stator bushing is provided in the area enclosed by several stators. The stator bushing is made of a high thermal conductivity material. One end of the stator bushing is in contact with the stator, and the other end is in contact with the torsion bar through a heat-conducting pin. The torsion bar is a temperature-sensitive elastic alloy bar that has undergone heat treatment. When the temperature of the torsion bar exceeds a preset value, the shear strength of the torsion bar decreases significantly.

3. The RV reduction drive assembly driven by an axial flux motor according to claim 1, characterized in that, The stator windings are embedded in a stator core encapsulated by a highly thermally conductive insulating material.

4. The RV reduction drive assembly driven by an axial flux motor according to claim 1, characterized in that, Both rotors are fixed on the same rotor hub.

5. The RV reduction drive assembly driven by an axial flux motor according to claim 1, characterized in that, The planetary gear train of the RV reducer unit also includes three planetary gears, which mesh with the sun gear; The RV reducer unit includes a crankshaft that rotates synchronously with the planetary gears. The crankshaft has an eccentric portion. The RV reducer unit also includes a cycloidal wheel that rotates with the eccentric portion and a number of pin teeth that mesh with the cycloidal wheel. The number of teeth on the cycloidal wheel is less than the number of pin teeth.

6. The RV reduction drive assembly driven by an axial flux motor according to claim 1, characterized in that, The rotor includes a turntable, on which are provided a plurality of permanent magnets spaced apart along its circumference. The magnetization direction of the permanent magnets is axial, and the magnetization directions of adjacent permanent magnets are opposite, so as to form alternating N poles and S poles on the surface of the turntable.

7. The RV reduction drive assembly driven by an axial flux motor according to claim 6, characterized in that, The permanent magnet is a tile-shaped magnet.

8. The RV reduction drive assembly driven by an axial flux motor according to claim 6, characterized in that, The rotor also includes a pressure plate, which is annular and presses and fixes the turntable axially from both sides of the turntable.

9. The RV reduction drive assembly driven by an axial flux motor according to claim 8, characterized in that, The pressure plate is made of a non-magnetic material.

10. The RV reduction drive assembly driven by an axial flux motor according to claim 2, characterized in that, One end of the axial spiral flow channel is connected to the inlet, and one end of the outlet flow channel is connected to the outlet. The cooling medium circuit where the inlet and outlet are located is equipped with a speed-adjustable cooling pump. A temperature sensor is provided on the stator bushing, and a thermal switch is provided between the stator bushing and the heat-conducting pin. The cooling pump, the temperature sensor, and the thermal switch are all connected to a controller. The base of the thermal switch is fixedly connected to the heat-conducting pin. The moving contact of the thermal switch is a heat-conducting contact that can move linearly. In the default state, the moving contact is separated from the stator bushing under the action of the spring to form a thermal isolation gap. When the electromagnetic actuator of the thermal switch receives the control signal from the controller, it drives the moving contact to overcome the spring force and press tightly against the stator bushing. When the temperature value detected by the temperature sensor is less than the first threshold, the cooling pump operates at the base speed; when the temperature value detected by the temperature sensor is greater than the first threshold and less than the second threshold, the cooling pump operates at a higher speed. When the temperature value detected by the temperature sensor is greater than the second threshold, the controller sends a control signal to the thermal switch to connect the heat conduction path between the stator bushing and the heat-conducting pin.

Images