An RV deceleration drive assembly driven by an axial flux motor

Abstract

The application provides an RV deceleration drive assembly driven by an axial flux motor, which comprises an axial flux motor unit and an RV decelerator unit connected with each other, the axial flux motor unit and the RV decelerator unit are integrated in a shell, the axial flux motor unit comprises a plurality of stators distributed in a ring shape, a disc type rotor is arranged on each side of the stator, a plurality of torsion bars are arranged on the rotor on the side of the RV decelerator unit and are uniformly distributed in a circumferential direction, the torsion bars are connected with a sun gear of a planetary gear train of the RV decelerator unit, and an output disc of the RV decelerator unit is a power output end. The RV deceleration drive assembly driven by the axial flux motor has the advantages of large starting torque, high mechanical efficiency, compact structure and strong overload capacity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transmission, in particular to an RV deceleration drive assembly driven by an axial flux motor. BACKGROUND

[0002] With the breakthrough and wide application of key technologies such as new energy batteries, motors and electric control systems, the field of non-road new energy vehicles such as logistics vehicles, intelligent AGVs and aerial work vehicles has experienced rapid development. During the working process, these engineering vehicles frequently switch between load and no-load states: the overall vehicle weight increases significantly in the load state, and the vehicle needs to complete tasks such as carrying, transferring or lifting heavy objects; in the no-load state, the vehicle needs to quickly move to the next working point to reduce the invalid working time and improve the overall operation efficiency. The functional characteristics of the vehicle determine that the kerb mass in the load state and the no-load state is quite different, so the vehicle driving system has clear dual requirements: in the load state, it needs to output low speed and large torque to meet the load bearing and running requirements; in the no-load state, it needs to have high speed and small torque output capability to realize quick scene switching.

[0003] At present, the mainstream scheme for realizing the driving function of the vehicle in the industry is to use a driving assembly combined with a permanent magnet synchronous motor and a planetary reducer. Although this structure has certain technical maturity, it still has several key defects in actual application, which restricts the optimization of the performance and structural layout of the whole machine:

[0004] Firstly, the power density of the driving assembly is low. Since the permanent magnet synchronous motor and the planetary reducer are combined as independent components, the system integration is limited, and the power output capability per unit volume or per unit mass is insufficient, which is difficult to meet the demand of non-road vehicles for compact and efficient power systems.

[0005] Secondly, the axial size of the permanent magnet synchronous motor itself is relatively long, which occupies a large space. In the vehicle arrangement, especially in the chassis part of engineering machinery or special vehicles with strict installation space limitations, the long motor size will significantly affect the layout of other components, increasing the difficulty and complexity of the vehicle design.

[0006] Thirdly, in order to achieve a larger transmission ratio, the planetary reducer often needs to use a multi-stage transmission structure, which directly leads to a significant increase in its axial size. For engineering vehicles with limited installation space and high structural compactness requirements, the excessive axial size limits the structural design of the whole machine and affects the passability and maneuverability of the vehicle in narrow or complex working conditions. SUMMARY

[0007] The present application solves the above technical problems and provides an RV deceleration drive assembly driven by an axial flux motor.

[0008] The technical scheme of the present application is an RV speed reduction drive assembly driven by an axial flux motor, comprising an axial flux motor unit and an RV speed reducer unit connected together, the axial flux motor unit and the RV speed reducer unit being integrated in a housing, the axial flux motor unit comprising a plurality of stators distributed in a ring shape, both sides of the stators being respectively provided with a disc type rotor, a plurality of torsion bars being uniformly distributed in a circumferential direction on the rotor towards the side where the RV speed reducer unit is located, the torsion bars being connected to a sun gear of a planetary gear train of the RV speed reducer unit, and an output disc of the RV speed reducer unit being a power output end.

[0009] As an embodiment, an axial spiral flow channel is arranged in the housing, the axial spiral flow channel surrounding the outer edge of the stator and being close to the outer profile of the stator, a radial micro flow channel being arranged between adjacent stators and being close to the side wall of the stator, one end of the radial micro flow channel being collected to a lead-in flow channel, the lead-in flow channel being connected to the axial spiral flow channel, and the other end of the radial micro flow channel being collected to a lead-out flow channel.

[0010] A stator bushing is arranged in the area enclosed by the plurality of stators, the stator bushing being made of a high thermal conductivity material, one end of the stator bushing being in contact with the stator, and the other end being in contact with the torsion bar through a thermal conduction pin, the torsion bar being a temperature sensitive elastic alloy rod after heat treatment, the shear strength of the torsion bar being greatly reduced when the temperature exceeds a preset value.

[0011] As an embodiment, the winding of the stator is embedded in a stator core encapsulated by a high thermal conductivity insulating material.

[0012] As an embodiment, the two rotors are fixed on the same rotor hub.

[0013] As an embodiment, the planetary gear train of the RV speed reducer unit further comprises three planetary gears engaged with the sun gear.

[0014] The RV speed reducer unit comprises a crank shaft rotating synchronously with the planetary gears, the crank shaft being provided with an eccentric part, the RV speed reducer unit further comprising a trochoid wheel rotatingly matched with the eccentric part and a plurality of pin teeth engaged with the trochoid wheel, the number of teeth of the trochoid wheel being less than the number of the pin teeth.

[0015] As an embodiment, the rotor comprises a rotating disc provided with a plurality of permanent magnets spacedly distributed in a circumferential direction of the rotating disc, the magnetization directions of the plurality of permanent magnets being axial, and the magnetization directions of adjacent permanent magnets being opposite to each other, so as to form N poles and S poles alternately distributed on the surface of the rotating disc.

[0016] As an embodiment, the permanent magnets are tile-shaped magnetic steels.

[0017] As an implementation form, the rotor further comprises a pressing plate, the pressing plate is annular, and the pressing plate axially presses and fixes the rotating disc from both sides of the rotating disc.

[0018] As an implementation form, the pressing plate is made of a non-magnetic conductive material.

[0019] As an implementation form, one end of the axial spiral flow channel is connected with an inlet, one end of the outlet flow channel is connected with an outlet, and a cooling pump capable of adjusting speed is arranged in a cooling medium circuit where the inlet and the outlet are located.

[0020] The stator sleeve is provided with a temperature sensor, a thermal switch is arranged between the stator sleeve and the heat-conducting pin, and the cooling pump, the temperature sensor and the thermal switch are connected with a controller.

[0021] The base of the thermal switch is fixedly connected with the heat-conducting pin, the movable contact of the thermal switch is a heat-conducting contact capable of linear motion, the movable contact is separated from the stator sleeve to form a thermal isolation gap under the action of a spring in a default state, and the electromagnetic actuator of the thermal switch drives the movable contact to tightly press the stator sleeve against the spring force when receiving a control signal of the controller.

[0022] When the temperature value detected by the temperature sensor is less than a first threshold value, the cooling pump operates at a basic speed; when the temperature value detected by the temperature sensor is greater than the first threshold value and less than a second threshold value, the cooling pump operates at a high speed; and when the temperature value detected by the temperature sensor is greater than the second threshold value, the controller sends a control signal to the thermal switch to connect the heat conduction path between the stator sleeve and the heat-conducting pin.

[0023] The beneficial effects of the present application compared with the prior art are:

[0024] I. The axial flux motor has high power density, large starting torque and higher mechanical efficiency than the permanent magnet synchronous motor;

[0025] II. The RV reducer has compact structure, strong overload capacity, high reduction transmission precision up to arc minute precision, and larger reduction transmission ratio than the planetary reduction in the same size;

[0026] III. The axial flux motor can realize stepless speed regulation in cooperation with the motor controller;

[0027] IV. The axial flux motor can increase oil cooling or water cooling flow channels in the motor to meet the high-power continuous working demand of engineering machinery;

[0028] V. The axial flux motor can be conveniently integrated with an electromagnetic brake having a reduction brake function, and the motor control cooperates with the back electromotive force of the axial flux motor to have excellent braking performance. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The first structural schematic diagram of the RV reduction drive assembly driven by the axial flux motor according to the embodiment of the present application is shown in the figure.

[0030] Figure 2 The second structural schematic diagram of the RV reduction drive assembly driven by the axial flux motor according to the embodiment of the present application is shown in the figure.

[0031] Figure 3 The partial enlarged view of the RV reduction drive assembly driven by the axial flux motor according to the embodiment of the present application is shown in the figure. Figure 1 The partial enlarged view of the thermal switch according to the embodiment of the present application is shown in the figure.

[0032] Figure 4 The partial enlarged view of the thermal switch according to the embodiment of the present application is shown in the figure.

[0033] In the figure: 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 spiral flow channel; 10, radial micro flow channel; 11, inlet flow channel; 12, outlet flow channel; 13, stator bushing; 14, heat conduction pin; 15, planetary gear; 16, crankshaft; 17, cycloid gear; 18, pin gear; 19, rotating disc; 20, permanent magnet; 21, pressing plate; 22, heat dissipation hole; 23, thermal switch; 24, base; 25, movable contact; 26, thermal isolation gap. DETAILED DESCRIPTION

[0034] The above and other embodiments and advantages of the present application will become more apparent from the following description of the embodiments of the present application, taken in conjunction with the accompanying drawings. It is to be understood that the described embodiments are merely part of the embodiments of the present application, but not all the embodiments of the present application.

[0035] In one embodiment, as shown in the figure. Figure 1

[0036] The RV reduction drive assembly driven by the axial flux motor according to the embodiment of the present application comprises the axial flux motor unit 1 and the RV reducer unit 2 connected with each other, and the axial flux motor unit 1 and the RV reducer unit 2 are integrated in a housing 3. The axial flux motor unit 1 comprises a plurality of stators 4 arranged in a ring shape, and a disc-shaped rotor 5 is arranged on each side of the stator 4. A plurality of torsion bars 6 are arranged on the rotor 5 on the side facing the RV reducer unit 2, and the torsion bars 6 are connected with the sun gear 7 of the planetary gear system of the RV reducer unit 2. The output disc 8 of the RV reducer unit 2 is the power output end.

[0037] ​In the embodiment, the problem of restricting the overall performance and structural layout optimization of the drive assembly using a combination of permanent magnet synchronous motor and planetary reducer mentioned in the background art. The axial flux motor driven RV reduction drive assembly, the flat structure of the axial flux motor can effectively shorten the axial size, and the double rotor design can improve the power density. In view to the problem of too long axial length of the reduction mechanism, the RV reducer has the characteristics of single-stage large transmission ratio, which can replace the multi-stage planetary reduction structure. By integrating the two units in the same housing 3, the connection space waste of the split structure can be eliminated. The key point is the direct power transmission path of the rotor 5 and the reducer, avoiding the axial extension caused by the traditional shaft coupling. Therefore, the drive assembly proposed in the embodiment includes an axial flux motor unit 1 and an RV reducer unit 2 connected to each other, both integrated in a housing 3. The axial flux motor unit 1 includes a plurality of stators 4 distributed in a ring shape, and disc rotors 5 are arranged on both sides of the stator 4, and the rotor 5 on the side facing the reducer is provided with a plurality of torsion bars 6 uniformly distributed in the circumferential direction, which are connected to the sun gear 7 of the planetary gear train of the RV reducer, and the output disc 8 of the reducer is used as the power output end.

[0038] Among them, the axial flux motor unit 1 refers to an electromagnetic energy conversion device with the magnetic field direction parallel to the motor axis, which can be realized by a symmetric structure of double-rotor clamping stator. The structure forms a rotating magnetic field through the ring-shaped distribution of the stator winding, and the two side rotating discs 19 rotate synchronously to generate torque. The disc rotor 5 refers to an axially extending disc-shaped rotating part, which can be realized by a metal disc body with an array of permanent magnets 20, and the symmetric arrangement can balance the axial magnetic pull. The circumferentially uniformly distributed torsion bars 6 are elastic transmission components arranged at equal angles along the circumference, which can be realized by columnar rods made of alloy steel, and the two ends are connected with the rotating disc 19 and the sun gear shaft respectively to realize the torque transmission and overload protection function. The axial flux motor unit 1 generates high power density torque through the double-rotor structure, and the rotor 5 rotates to drive 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 to drive the planetary gear train to perform primary reduction. The power after reduction is transmitted to the cycloidal gear train through the crank shaft 16 to complete secondary reduction, and finally a low-speed large torque is output by the output disc 8. The integrated housing 3 is used as a magnetic circuit closing component and a reducer support structure, eliminating the redundant space of the traditional split shell. The symmetric layout of the disc rotor 5 cancels the axial magnetic attraction force and reduces the bearing load, and the elastic deformation of the torsion bar 6 can buffer the impact load.

[0039] Compared with the drive assembly using a combination of permanent magnet synchronous motor and planetary reducer, the axial flux motor driven RV reduction drive assembly shortens the motor segment length through the axial flux motor, and the RV reducer realizes the transmission ratio of the traditional three-stage planetary reduction in a single stage, so that the overall axial size is greatly reduced. The integrated design combines the motor magnetic yoke and the reducer housing 3 into one, reducing the structural weight.

[0040] By the above technical solution, the power density of the power system is effectively improved, the volume is reduced under the same output power, the axial length is shortened, the vehicle chassis layout is more flexible, and the installation demand in narrow space is adapted. The integrated structure reduces the number of parts and improves the system reliability. The direct transmission path reduces energy loss and improves transmission efficiency. The torsion bar 6 can be elastically deformed to avoid damage to the mechanism when overloaded, and the service life is prolonged compared with the rigid coupling.

[0041] In one embodiment, as shown in Figures 1 to 3 .

[0042] The axial flux motor driven RV reduction drive assembly provided by the embodiment has an axial spiral flow channel 9 in the shell 3, the axial spiral flow channel 9 surrounds the outer edge of the stator 4 and closely abuts the outer profile of the stator 4, a radial micro flow channel 10 is arranged between adjacent stators 4, the radial micro flow channel 10 closely abuts the side wall of the stator 4, one end of the radial micro flow channel 10 converges to a lead-in flow channel 11, the lead-in flow channel 11 is connected with the axial spiral flow channel 9, the other end of the radial micro flow channel 10 converges to a lead-out flow channel 12; a stator sleeve 13 is arranged in the area enclosed by the plurality of stators 4, the stator sleeve 13 is made of high thermal conductivity material, one end of the stator sleeve 13 is in contact with the stator 4, and the other end is in contact with the torsion bar 6 through a heat conduction pin 14, the torsion bar 6 is a temperature-sensitive elastic alloy rod after heat treatment, and the shear strength of the torsion bar 6 is greatly reduced when the temperature exceeds a preset value.

[0043] In the embodiment, the axial flux motor driven RV reduction drive assembly, the axial spiral flow channel 9 refers to a spiral-shaped cooling medium channel extending along the axial direction of the shell 3, which can be specifically realized by a combination structure of a ring-shaped groove surrounding the outer edge of the stator 4 and a spiral flow guide piece, and the contact time of the cooling medium with the outer surface of the stator 4 is prolonged through the spiral path. The radial micro flow channel 10 refers to a small flow gap between the side walls of adjacent stators 4, which can be specifically realized by machining a groove with a depth of 0.5-1mm on the side of the stator core, forming a dense network of heat dissipation channels. The stator sleeve 13 refers to a ring-shaped heat conduction component arranged in the enclosed area of the stator 4, which can be specifically realized by a copper-aluminum alloy casting, and the outer surface thereof is in close contact with the end surface of the stator core. The heat conduction pin 14 refers to a heat transfer component connecting the stator sleeve 13 and the torsion bar 6, which can be specifically realized by a copper cylindrical pin with a nickel-plated surface, ensuring the continuity of the axial heat conduction path. The temperature-sensitive elastic alloy rod refers to a transmission component with temperature-strength response characteristics, which can be specifically realized by a nickel-titanium-based shape memory alloy after a graded aging heat treatment process, and the shear strength decreases by more than 50% in the temperature range of 80-100℃.

[0044] In this embodiment, the cooling medium flows axially along the outer edge of the stator 4 through the axial spiral flow channel 9, taking away the heat from the stator winding end and the outer surface of the core, and then is divided into each radial micro-flow channel 10 through the inlet flow channel 11, flows radially along the side wall of the stator 4 to cool the internal area of the core, and finally is discharged through the outlet flow channel 12. The heat generated by the operation of the stator 4 is conducted to the stator bushing 13 through the core, and is transmitted to the root of the torsion bar 6 through the heat conduction pin 14. When the system continues to operate under overload and the temperature abnormally rises, the heat quickly accumulates along this conduction path to the torsion bar 6, and when the temperature reaches the critical point of material phase change, the shear strength of the torsion bar 6 is actively reduced until it breaks, thereby cutting off the power transmission path. The traditional scheme that relies only on the heat dissipation of the surface of the motor shell cannot effectively remove the heat in the internal area of the stator 4 and the winding area. Compared with the traditional scheme, the three-dimensional heat dissipation network formed by the axial spiral flow channel 9 and the radial micro-flow channel 10 in this embodiment enables the cooling medium to directly contact the outer surface of the stator 4 and the gap between adjacent cores, significantly improving the heat dissipation efficiency. At the same time, a directional heat conduction path from the stator 4 to the torsion bar 6 is established, which, combined with the characteristics of temperature-sensitive materials, realizes active mechanical protection when the transmission system overheats, and avoids the damage of components caused by the response delay of temperature sensors in the traditional scheme.

[0045] In this embodiment, the problem of heat accumulation in the drive assembly caused by shortening the wheelbase and increasing the power density is effectively solved. That is, the heat in the stator 4 area is quickly removed through the three-dimensional heat dissipation network, and the working temperature of the key transmission parts is reduced. When abnormal temperature rise occurs, the heat conduction path directs the heat to the torsion bar 6, triggering the strength mutation characteristics to realize power cut-off, and completing system protection before the mechanical overload torque is reached.

[0046] In one embodiment, as shown in Figure 1 .

[0047] The RV reduction drive assembly driven by the axial flux motor provided in this embodiment has the winding of the stator 4 embedded in the stator core packaged by high-thermal-conductivity insulating material.

[0048] In the embodiment, the high-thermal-conductivity insulating material in the RV deceleration drive assembly driven by the axial flux motor refers to a non-metallic composite material with high thermal conductivity and meeting the electrical insulation requirements, and specifically can be implemented by using an aluminum nitride ceramic or an aluminum oxide ceramic filled epoxy resin. Such a material can ensure the insulation performance between the winding and the core while forming a high-efficiency heat conduction path. The packaging structure of the stator core refers to embedding the winding into the core slot completely and filling the high-thermal-conductivity insulating material through a molding process, and specifically can be implemented by using a vacuum pressure impregnation process. The structure makes the winding and the core form an integrated heat conduction body, and eliminates the air gap between the traditional winding and the core. The winding is completely wrapped in the core slot, the high-thermal-conductivity insulating material fills the gap between the winding and the core, and a continuous heat conduction interface is formed. The heat generated by the winding is directly conducted through the solid material conduction path without relying on air convection, and is discharged, thereby avoiding local temperature accumulation. The core packaging structure remains flat in the axial direction, and does not need to be additionally provided with heat dissipation fins or air ducts, thereby maintaining the compact overall size of the stator 4.

[0049] In the embodiment, the high-thermal-conductivity insulating material replaces the conventional insulating medium to quickly conduct the heat of the winding to the core, allows the winding to operate at a higher current density, and the packaging structure eliminates the protrusion of the traditional winding end, thereby reducing the axial space occupation. Through the above technical solution, the heat of the stator winding is directly conducted to the core through the high-thermal-conductivity insulating material, the power limitation caused by excessively high winding temperature rise is avoided, and the motor power density is improved. The packaging structure reduces the axial size of the stator 4, and adapts to the compact space layout requirement; the insulation property of the high-thermal-conductivity material ensures the electrical isolation reliability between the winding and the core, and avoids the short circuit risk.

[0050] In one embodiment, the two rotors 5 of the RV deceleration drive assembly driven by the axial flux motor are fixed on the same rotor hub.

[0051] In the embodiment, the rotor hub refers to a central support structure for fixing the two rotors 5, and specifically can be formed by precise casting or machining from a high-strength aluminum alloy material, and is internally provided with a key groove or spline structure matched with the motor shaft. The structure serves as a common installation reference of the two rotors, and can eliminate the accumulated error of the axial gap when the rotors are independently installed. In the axial flux motor unit 1, the two disc rotors 5 are fixed on the left and right end faces of the rotor hub in a symmetrical manner through bolting or welding. The rotor hub and the motor output shaft are connected in an interference fit or a key connection to realize synchronous rotation, so that the two rotors 5 form a rigid whole. Since the two rotors share the same support structure, it is not necessary to separately provide an installation flange and a positioning mechanism for each rotor 5, thereby reducing the axial space occupation. Meanwhile, the symmetrical design of the rotor hub makes the magnetic pole distribution of the two rotors 5 keep strictly coaxial, and avoids the magnetic field asymmetry phenomenon caused by assembly deviation.

[0052] In one embodiment, as shown in Figure 2

[0053] The axial flux motor driven RV reduction drive assembly provided by the embodiment further comprises three planetary gears 15 engaged with the sun gear 7; the RV reducer unit 2 comprises a crankshaft 16 rotating synchronously with the planetary gears 15, the crankshaft 16 is provided with an eccentric part, the RV reducer unit 2 further comprises a cycloid gear 17 rotating with the eccentric part and a plurality of pin teeth 18 engaged with the cycloid gear 17, the number of teeth of the cycloid gear 17 is less than the number of the pin teeth 18.

[0054] In the embodiment, the planetary gear 15 refers to a gear that revolves around the sun gear 7 and is engaged with the sun gear 7, which can be implemented by a involute tooth profile planetary gear 15, for transmitting the rotational motion of the sun gear 7 to the crankshaft 16. The crankshaft 16 refers to a shaft body rotating synchronously with the planetary gear 15, which can be implemented by an integral shaft structure made of medium carbon alloy steel, for converting the revolution motion of the planetary gear 15 into eccentric rotary motion. The eccentric part refers to a cylindrical protrusion on the crankshaft 16 deviating from the shaft center, which can be implemented by turning to form a geometry with an eccentricity, for driving the cycloid gear 17 to produce eccentric oscillation. The cycloid gear 17 refers to a disc-shaped gear with a cycloid tooth profile, which can be made of high-hardness bearing steel through heat treatment process, for engaging with the fixed pin teeth 18 to achieve speed reduction. The pin teeth 18 refer to cylindrical tooth pins uniformly distributed along the circumference, which can be implemented by alloy steel pins with surface nitriding treatment, for forming a meshing pair with the cycloid gear 17. The sun gear 7 drives the three planetary gears 15 to revolve around it through engagement, the planetary gears 15 drive the crankshaft 16 to rotate synchronously, and the eccentric part of the crankshaft 16 forces the cycloid gear 17 to perform eccentric rotary motion around its own axis. During the eccentric motion of the cycloid gear 17, its tooth profile continuously meshes with the fixed pin teeth 18, and since the number of teeth of the cycloid gear 17 is less than the number of pin teeth 18, the cycloid gear 17 lags a fixed angle relative to the pin teeth 18 after completing one eccentric rotary motion, thereby forming a speed reduction ratio. The two-stage reduction structure of the planetary gear train and the cycloid transmission is integrated on the same axis, the planetary gear train achieves one-stage reduction and disperses the load, and the cycloid transmission achieves two-stage large reduction ratio through tooth difference design, avoiding the axial superposition caused by traditional multi-stage planetary gear series connection.

[0055] In one embodiment, as shown in Figure 3

[0056] ​​The axial flux motor driven RV speed reduction drive assembly provided by the embodiment comprises a rotor 5, the rotor 5 comprises a rotating disc 19, the rotating disc 19 is provided with a plurality of permanent magnets 20 which are distributed along the circumference of the rotating disc 19, the magnetization direction of the plurality of permanent magnets 20 is axial, and the magnetization direction of adjacent permanent magnets 20 is opposite, so as to form N poles and S poles which are alternately distributed on the surface of the rotating disc 19. Preferably, the permanent magnet 20 is a tile-shaped magnetic steel.

[0057] In the embodiment, the rotating disc 19 refers to a ring-shaped metal base body which carries the permanent magnets 20, and can be made of aluminum alloy or low-carbon steel material. The rotating disc 19 serves as a rigid support structure for mounting the permanent magnets 20, and the permanent magnets 20 are arranged in a regular manner by being distributed along the circumference of the rotating disc 19. The permanent magnet 20 refers to a magnetic element which has an axial magnetization characteristic, and can be made of neodymium iron boron or samarium cobalt material. The magnetic field direction is consistent with the axial direction of the motor by setting the axial magnetization direction, so as to form effective magnetic coupling with the stator winding. The magnetization direction of adjacent permanent magnets 20 is opposite in the axial direction, and the magnetization direction of the permanent magnets 20 can be determined by using a magnetization mold, so that the surface of the rotating disc 19 forms a continuous N pole and S pole which are alternately distributed, and the magnetic leakage area between the magnetic poles is reduced. The permanent magnets 20 which are distributed along the circumference of the rotating disc 19 are arranged by optimizing the magnetic pole spacing, so as to improve the uniformity of the magnetic field distribution. The axial magnetization direction makes the magnetic field path extend along the axial direction of the motor, and forms a magnetic flux loop in the vertical direction with the stator winding. Compared with the traditional radial magnetization mode, the length of the magnetic circuit is shortened. The design that the magnetization direction of adjacent permanent magnets 20 is opposite forms an alternating N pole and S pole arrangement on the surface of the rotating disc 19, and the effective magnetic field strength is enhanced by the magnetic field gradient generated by the alternating polarity of the magnetic poles, and the magnetic flux leakage caused by the continuous distribution of single magnetic poles is eliminated. The layout mode equivalently improves the magnetic pole density by alternating the polarity under the premise of maintaining the number of magnetic poles, so as to achieve higher magnetic field utilization in a limited axial space.

[0058] In the embodiment, the tile-shaped magnetic steel refers to a magnetic body structure which has an arc-shaped cross section, and can be processed by a curved surface forming process using sintered neodymium iron boron material. The arc-shaped surface of the tile-shaped magnetic steel matches the circumferential curvature of the rotating disc 19. The tile-shaped magnetic steel and the surface of the rotating disc 19 form a surface contact by geometric shape matching, so as to reduce the magnetic resistance caused by the assembly gap.

[0059] In one embodiment, the rotor 5 of the axial flux motor driven RV speed reduction drive assembly further comprises a pressing plate 21, the pressing plate 21 is annular, and the pressing plate 21 presss and fixes the rotating disc 19 in the axial direction from both sides of the rotating disc 19.

[0060] In the embodiment, the pressing plate 21 refers to a ring-shaped structural component for applying axial pressure from both sides of the rotating disc 19 to achieve fixation, which can be implemented by a ring-shaped plate made of metal or composite material, and the vibration of the rotating disc 19 is suppressed by symmetric clamping. The rotating disc 19 refers to a rotating component for mounting the permanent magnet 20, which can be implemented by a disc body with circumferentially spaced permanent magnet 20 mounting grooves, and the displacement of the permanent magnet 20 is prevented by fixation of the pressing plate 21. The pressing plate 21 covers the entire circumferential area on both sides of the rotating disc 19, and the rotating disc 19 and the permanent magnet 20 are locked by the axial clamping force. The ring-shaped pressing plate 21 uniformly distributes pressure to avoid local stress concentration. The contact surface between the pressing plate 21 and the rotating disc 19 is designed as a plane to ensure uniform pressure transmission. When rotating at high speed, the symmetric constraint of the pressing plate 21 offsets the deformation of the rotating disc 19 caused by centrifugal force, and keeps the position of the permanent magnet 20 stable. The axial fixation method does not need to add a connecting structure in the radial direction of the rotating disc 19, which reduces the overall axial size of the rotor 5.

[0061] In an embodiment, the pressing plate 21 of the RV speed reduction drive assembly driven by the axial flux motor is made of a non-magnetic material.

[0062] In the embodiment, the non-magnetic material refers to a material with a magnetic permeability close to vacuum and does not participate in the conduction of the magnetic circuit, which can be implemented by aluminum alloy, austenitic stainless steel or titanium alloy. Its low magnetic permeability characteristic can block the propagation path of the magnetic field in the pressing plate 21.

[0063] In an embodiment, the rotating disc 19 of the RV speed reduction drive assembly driven by the axial flux motor is further provided with a plurality of heat dissipation holes 22 spaced along the circumference thereof.

[0064] In the embodiment, the circumferentially spaced distribution means that the heat dissipation holes 22 are arranged in a non-continuous manner around the circumferential direction of the rotating disc 19, which can be implemented by equal-angle interval or unequal-angle interval hole layout, and this distribution mode ensures uniform coverage of the heat dissipation area on the surface of the rotating disc 19. The heat dissipation hole 22 refers to a through-hole structure penetrating the thickness of the rotating disc 19, which can be implemented by a circular, elliptical or polygonal hole type, and the hole structure promotes heat exchange by increasing the contact area between the rotating disc 19 and the airflow.

[0065] In an embodiment, as shown in Figures 1 to 4 .

[0066] The axial flux motor driven RV speed reduction drive assembly provided by the embodiment comprises a shell 3, an axial spiral flow channel 9 arranged in the shell 3, the axial spiral flow channel 9 surrounding the outer edge of a stator 4 and closely abutting the outer profile of the stator 4, a radial micro flow channel 10 arranged between adjacent stators 4 and closely abutting the side wall of the stator 4, one end of the radial micro flow channel 10 converging to a lead-in flow channel 11, the lead-in flow channel 11 being connected with the axial spiral flow channel 9, the other end of the radial micro flow channel 10 converging to a lead-out flow channel 12, a stator bushing 13 arranged in the region surrounded by the stators 4, the stator bushing 13 being made of a high-thermal-conductivity material, one end of the stator bushing 13 being in contact with the stator 4 and the other end of the stator bushing 13 being in contact with a torsion bar 6 through a thermal conduction pin 14, the torsion bar 6 being a temperature-sensitive elastic alloy bar after heat treatment, the shear strength of the torsion bar 6 greatly reducing when the temperature exceeds a preset value.

[0067] One end of the axial spiral flow channel 9 is connected with an inlet, one end of the lead-out flow channel 12 is connected with an outlet, a cooling pump capable of adjusting speed is arranged in a cooling medium circuit where the inlet and the outlet are located, a temperature sensor is arranged on the stator bushing 13, a thermal switch 23 is arranged between the stator bushing 13 and the thermal conduction pin 14, and the cooling pump, the temperature sensor and the thermal switch 23 are all connected with a controller.

[0068] The base 24 of the thermal switch 23 is fixedly connected with the thermal conduction pin 14, the movable contact 25 of the thermal switch 23 is a thermal conduction contact capable of linear motion, the movable contact 25 is separated from the stator bushing 13 under the action of a spring in a default state to form a thermal isolation gap 26, and the electromagnetic actuator of the thermal switch 23 drives the movable contact 25 to tightly press against the stator bushing 13 against the spring force when receiving a control signal of the controller.

[0069] When the temperature value detected by the temperature sensor is less than a first threshold value, the cooling pump operates at a basic speed; when the temperature value detected by the temperature sensor is greater than the first threshold value and less than a second threshold value, the cooling pump operates at a high speed; and when the temperature value detected by the temperature sensor is greater than the second threshold value, the controller sends a control signal to the thermal switch 23 to connect the heat conduction path between the stator bushing 13 and the thermal conduction pin 14.

[0070] In the embodiment, the thermal switch 23 refers to a device that controls the on-off of the heat conduction path through electromagnetic actuation. Specifically, it can be implemented by using a separable heat conduction 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 for monitoring the temperature of the stator bushing 13. Specifically, it can be implemented by using a patch type thermocouple or a thin film resistance temperature sensor. Its function is to provide real-time temperature data for the cooling pump speed regulation and the action of the thermal switch 23. When the temperature sensor detects that the temperature of the stator bushing 13 is lower than the first threshold value, the controller maintains the cooling pump running at a basic speed, at which the cooling medium flow meets the regular heat dissipation demand. When the temperature rises between the first threshold value and the second threshold value, the controller increases the cooling pump speed to increase the cooling medium flow to enhance the heat dissipation capacity. When the temperature exceeds the second threshold value, the controller triggers the electromagnetic actuator to drive the moving contact 25 of the thermal switch 23 to press and combine with the base 24, thereby conducting the heat conduction path between the stator bushing 13 and the heat conduction pin 14, so that the heat is transmitted to the torsion bar 6 through the heat conduction pin 14 for dissipation.

[0071] In the embodiment, the temperature sensor is linked with the controller in real time to realize gradient adjustment of the cooling pump speed, and the thermal switch 23 is intelligently controlled to form a multi-stage temperature response mechanism. Compared with the conventional way of single-direction heat dissipation through a fixed flow channel, the combination of the axial spiral flow channel 9 and the radial micro through-flow channel 10 in the embodiment forms a three-dimensional heat dissipation network in the outer edge and gap area of the stator 4, significantly improving the heat dissipation area and efficiency. Moreover, the cooling medium flow is dynamically adjusted according to the actual temperature of the driving assembly, so that the cooling system can run at low energy consumption under normal working conditions and quickly enhance the heat dissipation capacity under high temperature working conditions. Through the active control of the thermal switch 23, an additional heat dissipation path is established under extreme temperature conditions to avoid the magnetic property attenuation caused by overheating of the stator 4. The synergistic effect of the axial spiral flow channel 9 and the radial micro through-flow channel 10 enables the cooling medium to cover the outer surface of the stator 4 and the gap area, eliminating local hot spots. The multi-stage temperature response mechanism takes into account the heat dissipation efficiency and energy consumption control, solves the problem of fluctuation of heat dissipation demand caused by frequent load switching of non-road vehicles, and prolongs the service life of the driving system.

[0072] The specific embodiments described above further illustrate the purposes, technical solutions and advantages of the present application. It should be understood that the above description is only a specific embodiment of the present application and does not limit the protection scope of the present application. It should be particularly pointed out that any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principles of the present application should be included in the protection scope of the present application.

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. 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 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. 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. 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.

2. 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.

3. 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.

4. 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.

5. 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 arranged 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.

6. The RV reduction drive assembly driven by an axial flux motor according to claim 5, characterized in that, The permanent magnet is a tile-shaped magnet.

7. The RV reduction drive assembly driven by an axial flux motor according to claim 5, 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.

8. The RV reduction drive assembly driven by an axial flux motor according to claim 7, characterized in that, The pressure plate is made of a non-magnetic material.

Images