Series-parallel hybrid power system and working method thereof

Abstract

The application relates to the technical field of vehicle power assemblies, and discloses a series-parallel hybrid power system and a working method thereof, which comprises an engine, an axle, coaxially arranged first-stage planetary gears, a first motor, second-stage planetary gears, a second motor, third-stage planetary gears, a gear shifting mechanism, a main reduction and differential mechanism. The engine is connected with a first-stage planet carrier, the first motor is connected with a first-stage sun gear, a first-stage ring gear is connected with a second-stage sun gear, a second-stage ring gear is fixed, a second-stage planet carrier is connected with a third-stage sun gear, a third-stage ring gear is connected with the gear shifting mechanism, and a third-stage planet carrier is connected with the main reduction and differential mechanism. The system realizes pure electric, series-parallel and direct drive modes by controlling the output of each power source and driving the gear shifting mechanism to switch between gears 1 and 2. When the gear is 2, the third-stage planetary gears are locked into a synchronous rotary body, gear meshing loss and oil resistance are eliminated, the transverse space is reduced, and the transmission efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of vehicle powertrain technology, specifically to a series-parallel hybrid powertrain system and its operating method. Background Technology

[0002] Hybrid electric vehicles have seen widespread adoption in recent years due to their excellent fuel economy and power performance. Traditional hybrid systems typically employ a parallel-axis configuration for the engine and dual electric motors. This parallel-axis configuration results in a large lateral space for the powertrain, severely limiting the vehicle's front compartment space and hindering the arrangement of the front suspension. To reduce space requirements, some systems have attempted to arrange the dual motors coaxially; however, existing coaxial systems suffer from a limited operating mode, making them unsuitable for complex driving conditions.

[0003] Under low-speed climbing conditions, vehicles require significant wheel-end drive torque. Fixed-ratio hybrid systems lack mechanical gear adjustment, preventing the engine and electric motor from amplifying their power and resulting in insufficient low-speed performance. Conversely, during high-speed cruising, the fixed-ratio system, due to its relatively high gear ratio, causes the engine speed to continuously increase, moving it out of its low-fuel-consumption operating range and increasing fuel consumption. Simultaneously, the electric motor experiences significant iron and windage losses at high speeds, reducing transmission efficiency.

[0004] While existing power-split hybrid systems can regulate engine speed, continuous relative motion exists between the components of the planetary gear mechanism during high-speed direct-drive. The high-speed meshing of the gears generates continuous frictional losses, and the high-speed agitation of the lubricating oil inside the transmission also creates significant oil churning resistance. This ineffective power cycle and resistance loss significantly reduces the vehicle's transmission efficiency during high-speed cruising, failing to achieve ideal fuel economy. Therefore, developing a compact, multi-mode hybrid system that also considers high-speed transmission efficiency is a current challenge. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a series-parallel hybrid power system and its operating method, which solves the problems of large lateral space size, insufficient wheel-end drive torque in low-speed conditions, low transmission efficiency in high-speed cruising conditions, and gear meshing losses and oil churning resistance in internal transmission components of traditional hybrid power systems.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The first aspect of the present invention provides a series-parallel hybrid power system, including an engine, a transmission housing and an axle. A first-stage planetary gear set is coaxially arranged at the output end of the engine. The first-stage planetary gear set is disposed inside the transmission housing. A first motor is arranged on the side of the first-stage planetary gear set. The output end of the first motor is connected to the first-stage planetary gear set. A second-stage planetary gear set is coaxially coupled to the output end of the first-stage planetary gear set. A second motor is connected to the inner side of the second-stage planetary gear set.

[0008] The output end of the second-stage planetary gear set is connected to the third-stage planetary gear set and the shifting mechanism. The output end of the third-stage planetary gear set and the shifting mechanism is connected to the main reduction gear and the differential mechanism.

[0009] Preferably, the first-stage planetary gear set includes a first-stage planetary gear set carrier, which is rigidly connected to the output shaft of the engine. A first-stage planetary gear set sun gear is disposed on the inner side of the first-stage planetary gear set carrier. The output shaft of the first motor is connected to the first-stage planetary gear set sun gear. A plurality of first-stage planetary gear sets are rotatably connected to the first-stage planetary gear set carrier. A first-stage planetary gear set ring gear is meshed with the outer sides of the plurality of first-stage planetary gear sets. The first-stage planetary gear set ring gear is connected to the second-stage planetary gear set.

[0010] Preferably, the second-stage planetary gear set includes a second-stage planetary gear set sun gear. The first-stage planetary gear set ring gear and the output end of the second motor are coaxially coupled to the second-stage planetary gear set sun gear. Multiple second-stage planetary gear set planetary gears are meshed on the outer side of the second-stage planetary gear set sun gear. A second-stage planetary gear set ring gear is arranged around the multiple second-stage planetary gear set planetary gears. The second-stage planetary gear set ring gear is fixedly connected to the gearbox housing. A second-stage planetary gear set planet carrier is rotatably connected to the second-stage planetary gear set planetary gears. The second-stage planetary gear set planet carrier is connected to the third-stage planetary gear set and the shifting mechanism.

[0011] Preferably, the third-stage planetary gear set and shifting mechanism includes a third-stage planetary gear set sun gear, the end of the second-stage planetary gear set planet carrier is fixedly connected to the third-stage planetary gear set sun gear, a plurality of third-stage planetary gear set planetary gears are meshed with the outer side of the third-stage planetary gear set sun gear, a third-stage planetary gear set planet carrier is rotatably connected to the plurality of third-stage planetary gear set planetary gears, the third-stage planetary gear set planet carrier is connected to the main reduction and differential mechanism, a third-stage planetary gear set ring gear is provided around the plurality of third-stage planetary gear set planetary gears, and the third-stage planetary gear set ring gear is connected to the shifting mechanism.

[0012] Preferably, the shifting mechanism includes a gear ring bracket connected between the third-stage planetary gear set and the gearbox housing. The shifting mechanism has a gear seat with a gear sleeve slidably connected to it. One side of the gear sleeve has a first gear engagement tooth that engages with the gear ring bracket, and the other side of the gear sleeve has a second gear engagement tooth that engages with the sun gear of the third-stage planetary gear set.

[0013] Preferably, the main reduction and differential mechanism includes a driving bevel gear, which is rigidly connected to the output end of the third-stage planetary gear set and shifting mechanism. A driven bevel gear is meshed with the outer side of the driving bevel gear, and a differential is fixedly connected to the side of the driven bevel gear. A differential housing is provided on the outer side of the differential, and the differential housing is rigidly connected to the driven bevel gear. A planetary gear is rotatably connected to the inner side of the differential housing, and half-shaft gears are meshed with both sides of the planetary gear.

[0014] Preferably, the output end of the half-shaft gear is connected to a wheel-side planetary gear reducer, and each end of the half-shaft gear on both sides is provided with a wheel-side planetary gear reducer. The wheel-side planetary gear reducer includes a wheel-side planetary gear sun gear. The half-shaft gear is connected to the wheel-side planetary gear sun gear. Multiple wheel-side planetary gears are meshed on the outer side of the wheel-side planetary gear sun gear. A wheel-side planetary gear ring gear is meshed on the outer side of the multiple wheel-side planetary gears. The wheel-side planetary gear ring gear is fixedly connected to the axle. A wheel-side planetary gear carrier is rotatably connected to the wheel-side planetary gears. The wheel-side planetary gear carrier is rigidly connected to the wheel.

[0015] Preferably, the engine, the first motor, the first-stage planetary gear set, the second motor, the second-stage planetary gear set, the third-stage planetary gear set, and the shifting mechanism share the same rotation center axis in spatial layout and are arranged coaxially.

[0016] A second aspect of the present invention provides a method for operating a series-parallel hybrid power system, comprising the following operating modes:

[0017] Pure electric drive mode: The engine stops working, the second motor outputs power to the sun gear of the second-stage planetary gear set, the power is transmitted through the planet carrier of the second-stage planetary gear set to the sun gear of the third-stage planetary gear set, the power is transmitted through the third-stage planetary gear set and the shifting mechanism and the main reduction and differential mechanism to the wheels, and the first motor rotates in conjunction with the ring gear of the first-stage planetary gear set.

[0018] Hybrid drive mode: The engine starts and drives the first-stage planetary gear carrier to rotate. The first motor rotates to generate electricity, which is transmitted to the second motor. The mechanical power output by the engine is transmitted to the sun gear of the second-stage planetary gear through the first-stage planetary gear ring gear. The second motor outputs power to the sun gear of the second-stage planetary gear. The combined power is transmitted to the sun gear of the third-stage planetary gear through the second-stage planetary gear carrier. The combined power is transmitted to the wheels through the third-stage planetary gear, the shifting mechanism, and the main reduction and differential mechanism.

[0019] Engine direct drive mode: The first motor is locked, the engine starts and drives the first-stage planetary gear carrier to rotate. Power is transmitted sequentially through the first-stage planetary gear ring, the second-stage planetary gear sun gear, and the second-stage planetary gear carrier to the third-stage planetary gear sun gear. Power is then transmitted to the wheels through the third-stage planetary gear in the second gear position, the shifting mechanism, and the main reduction and differential mechanism.

[0020] Preferably, the third-stage planetary gear set and shifting mechanism specifically perform the following gear shifting steps:

[0021] First gear shift: Axial movement of the gear sleeve, the gear sleeve engages with the first gear engagement gear, the gear ring bracket locks the third-stage planetary gear ring, power is input from the third-stage planetary sun gear, transmitted through the third-stage planetary gears to the third-stage planetary carrier and then to the main reduction and differential mechanism.

[0022] Second gear shift: Axial movement of the gear sleeve, engagement of the gear sleeve with the second gear engagement gear, locking the sun gear of the third-stage planetary gear set and the ring gear of the third-stage planetary gear set, the third-stage planetary gear set and the shifting mechanism rotate as a whole, and the power is directly transmitted from the sun gear of the third-stage planetary gear set to the planet carrier of the third-stage planetary gear set and then to the main reduction and differential mechanism.

[0023] This invention provides a series-parallel hybrid power system and its operating method. It has the following beneficial effects:

[0024] 1. The present invention connects the engine output end to the first motor through the first-stage planetary gear set, performs power splitting on the power input of the engine, decouples the rigid coupling relationship between engine speed and vehicle speed, and keeps the engine operating in a low fuel consumption range.

[0025] 2. This invention changes the fixed state of the third-stage planetary gear ring by axial displacement of the gear sleeve in the third-stage planetary gear set and the gear shifting mechanism between the first gear engagement teeth and the second gear engagement teeth. It performs deceleration transmission at low driving speed and locks the sun gear of the third-stage planetary gear set and the gear ring of the third-stage planetary gear set to achieve overall rotation at high speed cruising, thus eliminating the mechanical loss caused by the meshing operation of internal gears.

[0026] 3. This invention connects wheel-side planetary gear reducers to the ends of the two half-shafts respectively, and performs deceleration and torque amplification at a position close to the wheel. This reduces the torque borne by the front half-shaft and differential in power transmission, and reduces the overall space occupied by the main reduction and differential mechanisms in the gearbox. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall case device structure of the present invention;

[0028] Figure 2 This is a schematic diagram of the overall structure of the first-stage planetary array of the present invention;

[0029] Figure 3 This is a schematic diagram of the overall structure of the second-stage planetary array of the present invention;

[0030] Figure 4 This is a schematic diagram of the overall structure of the third-stage planetary gear set and shifting mechanism of the present invention;

[0031] Figure 5 This is a schematic diagram of the overall structure of the differential of the present invention;

[0032] Figure 6 This is a schematic diagram of the overall structure of the wheel-side planetary gear reducer of the present invention;

[0033] Figure 7 This is a schematic diagram of the power transmission path of the hybrid power system of the present invention in pure electric drive mode.

[0034] Figure 8 This is a schematic diagram of the power transmission path of the hybrid power system of the present invention in the hybrid drive mode.

[0035] Figure 9 This is a schematic diagram of the power transmission path of the hybrid power system of the present invention in engine direct drive mode;

[0036] Figure 10 This is a schematic diagram of the third-stage planetary gear set and shifting mechanism of the present invention in the first gear switching state.

[0037] Among them, 1. Engine; 2. First motor;

[0038] 3. First-stage planetary gear set; 3.1. First-stage planetary gear set sun gear; 3.2. First-stage planetary gear set planet gears; 3.3. First-stage planetary gear set planet carrier; 3.4. First-stage planetary gear set gear ring;

[0039] 4. Second motor;

[0040] 5. Second-stage planetary gear set; 5.1. Sun gear of the second-stage planetary gear set; 5.2. Planet gears of the second-stage planetary gear set; 5.3. Planet carrier of the second-stage planetary gear set; 5.4. Gear ring of the second-stage planetary gear set;

[0041] 6. Third-stage planetary gear set and shifting mechanism; 6.1. Sun gear of the third-stage planetary gear set; 6.2. Planet gears of the third-stage planetary gear set; 6.3. Planet carrier of the third-stage planetary gear set; 6.4. Ring gear of the third-stage planetary gear set; 6.5. Ring gear support; 6.6. Gear seat; 6.7. Gear sleeve; 6.8. First gear engagement gear; 6.9. Second gear engagement gear;

[0042] 7. Driving bevel gear; 8. Driven bevel gear;

[0043] 9. Differential; 9.1. Differential housing; 9.2. Planetary gears; 9.3. Half-shaft gears;

[0044] 10. Wheel-side planetary gear reducer; 10.1. Wheel-side planetary gear reducer sun gear; 10.2. Wheel-side planetary gear reducer planet gears; 10.3. Wheel-side planetary gear reducer planet carrier; 10.4. Wheel-side planetary gear reducer ring gear;

[0045] 11. Wheels. Detailed Implementation

[0046] The technical solutions in the embodiments 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Please see the appendix Figure 1 This invention provides a series-parallel hybrid power system, including an engine 1, a gearbox housing and an axle. The output end of the engine 1 is coaxially provided with a first-stage planetary gear set 3, which is disposed inside the gearbox housing. A first motor 2 is provided on the side of the first-stage planetary gear set 3, and the output end of the first motor 2 is connected to the first-stage planetary gear set 3. The output end of the first-stage planetary gear set 3 is coaxially coupled to a second-stage planetary gear set 5, and a second motor 4 is connected to the inner side of the second-stage planetary gear set 5.

[0048] The output of the second-stage planetary gear set 5 is connected to the third-stage planetary gear set and the shift mechanism 6. The output of the third-stage planetary gear set and the shift mechanism 6 is connected to the main reduction gear and the differential mechanism.

[0049] Specifically, engine 1 is used to output basic mechanical power; the gearbox housing is used to house and install internal transmission components; the axle is used to support the vehicle and bear the final power output; the first-stage planetary gear set 3 is used to split the power input from engine 1 and regulate the speed; the first motor 2 is used to start engine 1, regulate the speed, and absorb mechanical energy to generate electricity; the second-stage planetary gear set 5 is used to coaxially couple the mechanical power output from the first-stage planetary gear set 3 with the electric driving force output from the second motor 4; the second motor 4 is used to output pure electric driving power; the third-stage planetary gear set and shifting mechanism 6 are used to switch gears to change the transmission ratio, achieving deceleration and torque increase or direct transmission; the main reduction and differential mechanism are used to receive the power from the previous stage for deceleration and distribute the power to both wheels.

[0050] Please see the appendix Figure 1 and attached Figure 2 The first-stage planetary gear set 3 includes a first-stage planetary gear set carrier 3.3, which is rigidly connected to the output shaft of the engine 1. A first-stage planetary gear set sun gear 3.1 is provided on the inner side of the first-stage planetary gear set carrier 3.3. The output shaft of the first motor 2 is connected to the first-stage planetary gear set sun gear 3.1. Multiple first-stage planetary gear set planetary gears 3.2 are rotatably connected to the first-stage planetary gear set carrier 3.3. A first-stage planetary gear set ring gear 3.4 is meshed with the outer side of the multiple first-stage planetary gear set planetary gears 3.2. The first-stage planetary gear set ring gear 3.4 is connected to the second-stage planetary gear set 5.

[0051] Specifically, the first-stage planetary carrier 3.3 receives power from the engine 1 and supports the rotation of multiple first-stage planetary gears 3.2; the first-stage planetary sun gear 3.1 connects to the first motor 2, transmitting the torque of the first motor 2 or transmitting power to the first motor 2 for power generation; the multiple first-stage planetary gears 3.2 connect the first-stage planetary sun gear 3.1 and the first-stage planetary ring gear 3.4 for internal power transmission and distribution; the first-stage planetary ring gear 3.4 outputs the adjusted mechanical power to the second-stage planetary set 5.

[0052] Please see the appendix Figure 1 and attached Figure 3 The second-stage planetary gear set 5 includes a second-stage planetary gear set sun gear 5.1. The output ends of the first-stage planetary gear set ring gear 3.4 and the second motor 4 are coaxially coupled to the second-stage planetary gear set sun gear 5.1. Multiple second-stage planetary gear set planetary gears 5.2 are meshed on the outer side of the second-stage planetary gear set sun gear 5.2. The multiple second-stage planetary gear set planetary gear set planetary gears 5.2 are surrounded by a second-stage planetary gear set ring gear 5.4. The second-stage planetary gear set ring gear 5.4 is fixedly connected to the gearbox housing. The second-stage planetary gear set planet carrier 5.3 is rotatably connected to the second-stage planetary gear set planetary gears 5.2. The second-stage planetary gear set planet carrier 5.3 is connected to the third-stage planetary gear set and the shifting mechanism 6.

[0053] Specifically, the second-stage planetary gear set sun gear 5.1 is used to receive and couple the mechanical power output from the first-stage planetary gear set ring gear 3.4 with the electric driving force output from the second motor 4; multiple second-stage planetary gear set planetary gears 5.2 are used to connect the second-stage planetary gear set sun gear 5.1 and the second-stage planetary gear set ring gear 5.4 for power transmission; the second-stage planetary gear set ring gear 5.4 is used to provide fixed mechanical constraints to realize internal speed reduction and torque amplification transmission; the second-stage planetary gear set planetary carrier 5.3 is used to support the second-stage planetary gear set planetary gears 5.2 and output the coupled and reduced power to the third-stage planetary gear set and shifting mechanism 6.

[0054] Please see the appendix Figure 1 and attached Figure 4 The third-stage planetary gear set and shifting mechanism 6 includes a third-stage planetary gear set sun gear 6.1. The end of the second-stage planetary gear set planet carrier 5.3 is fixedly connected to the third-stage planetary gear set sun gear 6.1. Multiple third-stage planetary gear set planetary gears 6.2 are meshed on the outer side of the third-stage planetary gear set sun gear 6.2. A third-stage planetary gear set planet carrier 6.3 is rotatably connected to the multiple third-stage planetary gear set planetary gears 6.2. The third-stage planetary gear set planet carrier 6.3 is connected to the main reduction and differential mechanism. A third-stage planetary gear set ring gear 6.4 is arranged around the multiple third-stage planetary gear set planetary gears 6.2. The third-stage planetary gear set ring gear 6.4 is connected to the shifting mechanism 6.

[0055] The shift mechanism 6 includes a gear ring support 6.5, which is connected between the third-stage planetary gear ring 6.4 and the gearbox housing. A gear seat 6.6 is provided inside the shift mechanism, and a gear sleeve 6.7 is slidably connected to the gear seat 6.6. A first gear engagement tooth 6.8 is provided on one side of the gear sleeve 6.7, which engages with the gear ring support 6.5. A second gear engagement tooth 6.9 is provided on the other side of the gear sleeve 6.7, which engages with the sun gear 6.1 of the third-stage planetary gear set.

[0056] Specifically, the third-stage planetary set sun gear 6.1 receives power from the second-stage planetary set planet carrier 5.3; multiple third-stage planetary set planet gears 6.2 connect the third-stage planetary set sun gear 6.1 and the third-stage planetary set ring gear 6.4 for power transmission; the third-stage planetary set planet carrier 6.3 supports the multiple third-stage planetary set planet gears 6.2 and outputs the transmitted power to the main reduction and differential mechanisms; the third-stage planetary set ring gear 6.4 cooperates with the shifting mechanism 6 to change the motion constraint state to adjust the transmission ratio; the ring gear support 6.5 is used for... The third-stage planetary gear ring 6.4 is supported and connected; the gear seat 6.6 provides an axial sliding mounting base for the gear sleeve 6.7; the gear sleeve 6.7 is used to selectively engage with the external engagement teeth during sliding to switch gears; the first gear engagement tooth 6.8 is used to fix the third-stage planetary gear ring 6.4 when engaged with the gear sleeve 6.7, realizing the first gear reduction transmission; the second gear engagement tooth 6.9 is used to connect and lock the third-stage planetary gear sun gear 6.1 and the third-stage planetary gear ring 6.4 when engaged with the gear sleeve 6.7, realizing the second gear direct transmission.

[0057] Please see the appendix Figure 1 Appendix Figure 5 and attached Figure 6 The main reduction and differential mechanism includes a driving bevel gear 7, which is rigidly connected to the output end of the third-stage planetary gear set and shifting mechanism 6. A driven bevel gear 8 is meshed on the outer side of the driving bevel gear 7. A differential 9 is fixedly connected to the side of the driven bevel gear 8. A differential housing 9.1 is provided on the outer side of the differential 9. The differential housing 9.1 is rigidly connected to the driven bevel gear 8. A planetary gear 9.2 is rotatably connected to the inner side of the differential housing 9.1. Half-shaft gears 9.3 are meshed on both sides of the planetary gear 9.2.

[0058] The output end of the half-shaft gear 9.3 is connected to a wheel-side planetary gear reducer 10. Each half-shaft gear 9.3 on both sides is equipped with a wheel-side planetary gear reducer 10. The wheel-side planetary gear reducer 10 includes a wheel-side planetary gear sun gear 10.1. The half-shaft gear 9.3 is connected to the wheel-side planetary gear sun gear 10.1. Multiple wheel-side planetary gears 10.2 are meshed on the outer side of the wheel-side planetary gears 10.2. Wheel-side planetary gear ring gears 10.4 are meshed on the outer side of the multiple wheel-side planetary gears 10.2. The wheel-side planetary gear ring gear 10.4 is fixedly connected to the axle. A wheel-side planetary gear carrier 10.3 is rotatably connected to the wheel-side planetary gears 10.2. The wheel-side planetary gear carrier 10.3 is rigidly connected to the wheel 11.

[0059] Specifically, the driving bevel gear 7 receives power from the third-stage planetary gear set and shifting mechanism 6 and drives the driven bevel gear 8 to rotate; the driven bevel gear 8 receives power from the driving bevel gear 7 and drives the differential housing 9.1 to rotate; the differential 9 distributes power to the half-shaft gears 9.3 on both sides and allows for a speed difference between the two sides; the differential housing 9.1 supports the planetary gears 9.2 installed inside it and drives them to rotate synchronously; the planetary gears 9.2 balance the driving resistance on both sides and rotate on their own when needed to achieve vehicle differential; the half-shaft gears 9.3 receive power distributed by the differential 9 and output it to the wheel-side planetary gear set reducers 10 on both sides; the wheel-side planetary gear set reducers 10... The speed reducer 10 is used to further reduce speed and amplify torque at the wheel end; the wheel-side planetary set sun gear 10.1 is used to receive the power input from the half-shaft gear 9.3 and drive the multiple wheel-side planetary set planet gears 10.2; the multiple wheel-side planetary set planet gears 10.2 are used to connect the wheel-side planetary set sun gear 10.1 and the wheel-side planetary set ring gear 10.4 for end transmission; the wheel-side planetary set ring gear 10.4 is used to provide fixed mechanical constraints to achieve the speed reduction effect of the planetary gear mechanism; the wheel-side planetary set planet carrier 10.3 is used to support the wheel-side planetary set planet gears 10.2 and finally output the power after speed reduction and torque amplification; the wheel 11 is used to receive the driving force output by the transmission system for driving.

[0060] Please see the appendix Figure 1 The engine 1, the first motor 2, the first-stage planetary gear set 3, the second motor 4, the second-stage planetary gear set 5, the third-stage planetary gear set, and the shifting mechanism 6 share the same rotation center axis in spatial layout and are arranged coaxially.

[0061] Specifically, engine 1 provides mechanical power input on the same axis; first motor 2 is used for speed regulation or power generation on the same rotational axis; first-stage planetary gear set 3 is used for power distribution of the input power on the same rotational axis; second motor 4 is used for outputting electric drive torque along the same rotational axis; second-stage planetary gear set 5 is used for coaxial mechanical coupling of multiple power sources on the same rotational axis; third-stage planetary gear set and shifting mechanism 6 are used to change the transmission ratio and output power by shifting gears on the same rotational axis; the same rotational axis serves as the common rotational axis of the above power sources and transmission components to reduce the radial space dimension of the power system.

[0062] See attached document Figure 7In pure electric drive mode, the hybrid power system of this invention is driven by a single power source. Specifically, the control system cuts off the power input from engine 1, and the driving torque required for the vehicle is entirely provided by the second motor 4. To match the torque demand of the vehicle under different driving speeds and load conditions, and to optimize the energy utilization efficiency of the power system, an axial shift selection is performed between the first gear shifting state and the second gear shifting state via a shift mechanism. At the same time, utilizing the coaxial rigid coaxial connection between the first-stage planetary gear set 3 and the second-stage planetary gear set 5, the first motor 2 is allowed to idle under the mechanical constraints of specific components, thereby avoiding additional interference and drag losses to the drive circuit.

[0063] The vehicle controller collects the battery's charge status and the driver's pedal input signal in real time. When it determines that the remaining battery charge is higher than a preset threshold (e.g., within a closed range of 25% to 95%), and the vehicle's required torque corresponding to the driver's pedal input signal is less than a preset upper limit threshold for pure electric drive torque, the control system enters pure electric drive mode. If the remaining charge or required torque does not meet the above limits, the vehicle controller automatically switches to hybrid drive mode to avoid control logic dead zones. When the pure electric drive conditions are met, the vehicle controller sends a stop command to the engine 1 control unit, keeping the engine 1 in a stopped state, cutting off the fuel supply and ignition of the engine 1, so that the output shaft of the engine 1 has no power output, i.e., the engine 1 does not work.

[0064] The vehicle controller sends a drive command to the inverter of the second motor 4. The DC power output from the power battery is converted into AC power by the inverter and delivered to the second motor 4, controlling the second motor 4 to enter the electric operation mode. The rotor shaft of the second motor 4 generates drive torque, which directly drives the second-stage planetary sun gear 5.1, which is rigidly connected to the output end of the second motor 4, to rotate. That is, the second motor 4 drives the second-stage planetary sun gear 5.1.

[0065] Since the second-stage planetary gear ring 5.4 is fixedly connected to the gearbox housing, the rotation of the second-stage planetary gear sun gear 5.1 drives multiple second-stage planetary gears 5.2 to rotate and revolve within the second-stage planetary gear ring 5.4, thereby driving the second-stage planetary carrier 5.3 to decelerate and increase torque. The second-stage planetary carrier 5.3 coaxially transmits the driving torque to the third-stage planetary gear sun gear 6.1. That is, because the second-stage planetary gear ring 5.4 is fixed, the power is transmitted to the third-stage planetary gear sun gear 6.1 after being decelerated and increased in torque by the second-stage planetary carrier 5.3.

[0066] While power is transmitted from the second-stage planetary gear set sun gear 5.1 to the next stage, the torque of the second-stage planetary gear set sun gear 5.1 is input in reverse to the first-stage planetary gear set sun gear 3.4 because the first-stage planetary gear set ring gear 3.4 is coaxially fixed on the second-stage planetary gear set sun gear 5.1. The rotation of the first-stage planetary gear set ring gear 3.4 drives multiple first-stage planetary gear set planetary gears 3.2 to rotate on the first-stage planetary gear set planetary carrier 3.3, which is kept stationary due to the inherent mechanical resistance and reverse damping of the engine. This overcomes the rotational inertia of the first motor 2 and drives the first-stage planetary gear set sun gear 3.1 to rotate, causing the rotor of the first motor 2 connected to the first-stage planetary gear set sun gear 3.1 to follow and rotate idling. In this mode, the first motor 2 is followed by the first-stage planetary gear set ring gear 3.4. If the first motor 2 does not generate electricity, it will idle.

[0067] When the vehicle controller determines that the vehicle is in a starting or low-speed climbing condition with a large operating load, it sends a first gear control command to the shift actuator, i.e., if the shift actuator is in 1st gear; the shift actuator drives the gear sleeve 6.7 to move axially towards the first side on the gear seat 6.6, so that the gear sleeve 6.7 engages with the first gear engagement gear 6.8, and the third-stage planetary gear ring 6.4 is locked and fixed to the gearbox housing through the gear ring bracket 6.5; at this time, the power input from the second-stage planetary carrier 5.3 to the third-stage planetary sun gear 6.1 drives multiple third-stage planetary gears 6.2 to revolve inside the locked third-stage planetary gear ring 6.4, driving the third-stage planetary carrier 6.3 to perform deceleration transmission, and the power is output from the third-stage planetary carrier 6.3 to the main reduction and differential mechanism, i.e., the power is output from the third-stage planetary carrier 6.3.

[0068] When the vehicle controller determines that the vehicle speed has reached or exceeded a preset speed threshold, such as within the range of 35km / h to 45km / h, it sends a second gear control command to the shift actuator. That is, if the shift actuator is locked in 2nd gear, the shift actuator drives the gear sleeve 6.7 to move axially towards the second side on the gear seat 6.6, so that the gear sleeve 6.7 engages with the second gear engagement gear 6.9. The gear sleeve 6.7 locks the third-stage planetary gear set sun gear 6.1 and the third-stage planetary gear set ring gear 6.4 together, reducing the relative movement between the internal components of the third-stage planetary gear set. The third-stage planetary gear set and the shift mechanism 6 form a synchronized rotating body and rotate synchronously with the central axis. Power is directly transmitted from the third-stage planetary gear set sun gear 6.1 to the third-stage planetary gear set planet carrier 6.3, and power is output from the third-stage planetary gear set planet carrier 6.3 to the main reduction and differential mechanism, that is, power is directly output.

[0069] The power output from the third-stage planetary gear carrier 6.3 is transmitted to the main reduction gear and differential mechanism, driving the driving bevel gear 7 to rotate. The driving bevel gear 7 drives the driven bevel gear 8 to rotate through the outer meshing transmission. The driven bevel gear 8 drives the differential housing 9.1, which is fixedly connected to the driven bevel gear 8, to rotate. Multiple planetary gears 9.2 installed inside the differential housing 9.1 rotate with the differential housing 9.1, and the power is distributed to the half-shaft gears 9.3 on both sides through the multiple planetary gears 9.2.

[0070] The half-shaft gears 9.3 on both sides independently transmit power to the corresponding wheel-side planetary gear reducer 10. The power input is to the wheel-side planetary gear sun gear 10.1 and drives multiple wheel-side planetary gears 10.2 to rotate. Since the wheel-side planetary gear ring 10.4 is fixedly connected to the axle, the multiple wheel-side planetary gears 10.2 revolve inside the wheel-side planetary gear ring 10.4 and drive the wheel-side planetary gear carrier 10.3 to rotate. The wheel-side planetary gear carrier 10.3 ultimately drives the rigidly connected wheel 11 to rotate and travel.

[0071] See attached document Figure 8 In the parallel-parallel hybrid drive mode, the parallel-parallel hybrid system of this invention utilizes the coordinated operation of multiple power sources, namely engine 1, first motor 2, and second motor 4. The core principle of this mode lies in using the mechanical differential characteristics of the first-stage planetary gear set 3 to spatially split the power input from engine 1. Part of the power is directly transmitted to the rear end of the transmission system via a mechanical path, while the other part is converted into electrical energy by the first motor 2. This electrical energy can be stored in the power battery or directly transmitted to the second motor 4 for electric drive output. Finally, mechanical and electrical energy are coaxially coupled again at the input end of the second-stage planetary gear set 5 to meet the torque and speed requirements of the vehicle under complex operating conditions.

[0072] The vehicle controller monitors the battery's charge status and the vehicle's drive torque requirements in real time. When the remaining battery charge is determined to be below a preset threshold (e.g., within a closed range of 10% to 25%), or when the required torque for the vehicle when the driver depresses the accelerator pedal exceeds a preset electric drive capability limit (e.g., exceeding 300 N·m), the control system issues a control command to enter hybrid drive mode. If neither the remaining battery charge nor the required torque meets the above conditions, the control system maintains pure electric drive mode or another predetermined drive mode, thus eliminating the logical dead zone during control mode switching. The vehicle controller assigns a torque control target to the control unit of the first motor 2 and simultaneously sends a start request to the control unit of the engine 1.

[0073] The first motor 2 receives control current input from the first motor controller and enters electric operation. The output shaft of the first motor 2 transmits reverse torque to the output shaft of the engine 1 through the sun gear 3.1 and the planetary carrier 3.3 of the first-stage planetary gear set, thereby increasing the speed of the engine 1 to a preset operating speed. Preferably, the preset operating speed is in the range of 1000 rpm to 1200 rpm. The control unit of the engine 1 controls the fuel supply system and ignition system to start working. After the engine 1 detects the speed signal, it ignites and starts to output power. The output shaft of the engine 1 continuously inputs speed and torque to the planetary carrier 3.3 of the first-stage planetary gear set.

[0074] The power input from engine 1 is split within the first-stage planetary gear set 3. The rotation of the planet carrier 3.3 of the first-stage planetary gear set drives the rotation of multiple planetary gears 3.2. The first motor 2 applies a reverse balancing torque through the sun gear 3.1 of the first-stage planetary gear set and enters power generation mode, thereby converting a portion of the mechanical energy input from engine 1 into electrical energy output. The remaining portion of the mechanical energy input from engine 1 is transmitted to the ring gear 3.4 of the first-stage planetary gear set through the mechanical meshing of the multiple planetary gears 3.2 for output. During the flow regulation process, since the rotational speeds of the first-stage planetary gear sun gear 3.1, the first-stage planetary gear carrier 3.3, and the first-stage planetary gear ring gear 3.4 are constrained by the rigid kinematic constraints of the planetary gear mechanism, the power is generated or the speed is adjusted by regulating the rotational speed of the first motor 2. Part of the power is directly transmitted to the second-stage planetary gear sun gear 5.1 to drive the wheels via the first-stage planetary gear ring gear 3.4, while the other part of the power is generated by the first motor 2, and the electrical energy is supplied to the second motor 4 to drive the wheels, thus realizing the continuous variable transmission ratio. At the same time, by regulating the rotational speed of the first-stage planetary gear sun gear 3.1, the relative speed ratio between the first-stage planetary gear carrier 3.3 and the first-stage planetary gear ring gear 3.4 can be changed, thereby decoupling the rotational speed of the engine 1 and adjusting it to the preset low fuel consumption operating range.

[0075] The alternating current generated by the first motor 2 is converted into direct current by the first motor controller and input to the power battery bus, or it is directly converted into alternating current by the second motor inverter and sent to the second motor 4. The second motor 4 receives electrical energy, enters the electric driving mode, and outputs driving torque. The output terminal of the second motor 4 directly applies the driving torque to the sun gear 5.1 of the second-stage planetary gear set.

[0076] Since the output ends of the first-stage planetary gear ring 3.4 and the second motor 4 are both coaxially mechanically connected to the sun gear 5.1 of the second-stage planetary gear ring, the mechanical power output by the first-stage planetary gear ring 3.4 and the electric drive torque output by the second motor 4 are combined at the position of the sun gear 5.1 of the second-stage planetary gear ring, realizing the coaxial mechanical superposition and coupling of the two power sources.

[0077] Inside the second-stage planetary gear set 5, the second-stage planetary gear ring 5.4 is fixedly connected to the gearbox housing. The second-stage planetary gear set sun gear 5.1 carries the coupled power and rotates, driving multiple second-stage planetary gear sets 5.2 to rotate and revolve within the second-stage planetary gear ring 5.4. The revolve motion drives the second-stage planetary gear set planet carrier 5.3 to rotate, reducing the output shaft speed and correspondingly increasing the output shaft torque. The second-stage planetary gear set planet carrier 5.3 transmits the coupled power to the rear of the drive shaft to the third-stage planetary gear set sun gear 6.1.

[0078] When the vehicle controller determines from the vehicle speed sensor signal that the vehicle is in a low-speed, high-load state, such as between 0 km / h and 45 km / h, the shift mechanism 6 performs a first gear shift. The shift actuator drives the gear sleeve 6.7 to move axially towards the first side on the gear seat 6.6. The gear sleeve 6.7 engages with the first gear engagement gear 6.8, and the third-stage planetary gear ring 6.4 is fixed to the gearbox housing via the gear ring bracket 6.5. The power input from the third-stage planetary gear sun gear 6.1 drives multiple third-stage planetary gears 6.2 to revolve within the fixed third-stage planetary gear ring 6.4, driving the third-stage planetary gear carrier 6.3 to decelerate and rotate, thus outputting power.

[0079] When the vehicle controller determines that the vehicle speed has reached the cruising speed range based on the vehicle speed sensor signal (e.g., between 35 km / h and 120 km / h) and meets the shift hysteresis curve for transitioning from a low gear to a high gear, the shift mechanism 6 executes the second gear shift. The shift actuator drives the gear sleeve 6.7 to move axially towards the second side on the gear seat 6.6. The gear sleeve 6.7 engages with the second gear engagement gear 6.9, locking the third-stage planetary set sun gear 6.1 and the third-stage planetary set ring gear 6.4 together, restricting the relative movement between the internal components of the third-stage planetary set, forming a synchronized rotating body. Power is transmitted from the third-stage planetary set sun gear 6.1 to the third-stage planetary set planet carrier 6.3 and output.

[0080] The power output from the third-stage planetary gear carrier 6.3 is transmitted to the main reduction gear and differential mechanism, and finally the rigidly connected wheel 11 is driven to rotate by the wheel-side planetary gear carrier 10.3.

[0081] See attached document Figure 9In engine direct drive mode, the hybrid power system of this invention mainly operates when the vehicle is cruising at medium to high speeds. The control principle involves adding a locking device to the first motor 2. This physical locking structure fixes the rotor of the first motor 2, causing the first-stage planetary gear set 3 to change from a power-split state with varying speed ratios to a mechanically accelerated transmission state with a fixed speed ratio. The engine 1 then independently provides the driving energy required for the vehicle's movement. Simultaneously, the shifting mechanism controls the third-stage planetary gear set and shifting mechanism 6 to be in the second gear shifting state. This locks the gear components inside the third-stage planetary gear set and shifting mechanism 6, forming a synchronized rotating body. During high-speed cruising, locking the third-stage planetary gear set (shifting mechanism) in second gear eliminates gear meshing losses, allowing engine power to be directly transmitted to the final drive and differential mechanism (differential) at a 1:1 speed ratio, thereby improving fuel economy.

[0082] The vehicle controller collects real-time data on the vehicle's speed, driving resistance, and the battery's charge status. When the vehicle speed meets the preset high-speed cruising speed limit (set within a closed range of 80km / h to 120km / h) and the driver's required torque is within the stable cruising resistance range (set between 50N·m and 150N·m), the control system issues a control command to enter engine direct drive mode. To prevent frequent switching oscillations at mode boundaries, hysteresis control logic is introduced. If the vehicle speed drops to a preset exit threshold (set below 75km / h) and the vehicle's acceleration resistance increases, causing the required torque to exceed 200N·m, the control system automatically exits engine direct drive mode and switches to hybrid drive mode, thus avoiding logical decision dead zones in the control system.

[0083] After the boundary conditions for entering the engine direct drive mode are met, the vehicle controller sends a lock activation command to the locking device corresponding to the first motor 2. The locking device adopts a mechanical locking pin and a friction brake structure. After receiving the command, it drives the friction components to generate displacement through a hydraulic control valve combined with an electromagnetic actuator, applying a physical locking reaction force to the rotor shaft of the first motor 2, restricting the rotation of the rotor of the first motor 2 and putting it in a locked state; since the first-stage planetary gear sun gear 3.1 is coaxially rigidly connected to the output shaft of the first motor 2, the first-stage planetary gear sun gear 3.1 simultaneously enters the locked and fixed state.

[0084] Engine 1 operates within a predetermined low-fuel-consumption stable operating range, and its output shaft continuously inputs power to the first-stage planetary carrier 3.3 of the first-stage planetary gear set 3. With the sun gear 3.1 locked in a constrained state, the rotational motion of the first-stage planetary carrier 3.3 forces multiple first-stage planetary gears 3.2 to revolve around the sun gear 3.1, driving the first-stage planetary gear ring 3.4 to rotate through the mechanical tooth meshing on the outer side, thus achieving a speed-increasing power transmission from the first-stage planetary carrier 3.3 to the first-stage planetary gear ring 3.4.

[0085] The mechanical power output from the first-stage planetary gear ring 3.4 is directly transmitted to the coaxially coupled second-stage planetary gear sun gear 5.1. In this state, the vehicle controller sends a zero-torque control command to the inverter of the second motor 4, so that the second motor 4 does not output active drive torque, and the rotor shaft of the second motor 4 passively follows the rotation of the second-stage planetary gear sun gear 5.1.

[0086] During the internal transmission process of the second-stage planetary gear set 5, since the second-stage planetary gear set ring gear 5.4 is rigidly fixed to the gearbox housing, the power input to the second-stage planetary gear set sun gear 5.1 drives multiple second-stage planetary gear set planetary gears 5.2 to rotate and revolve within the fixed second-stage planetary gear set ring gear 5.4, thereby driving the second-stage planetary gear set planet carrier 5.3 to decelerate and rotate. The second-stage planetary gear set planet carrier 5.3 inputs the engine power, whose overall speed ratio has not changed due to the gear ratio matching of the first two planetary gear sets, to the rear of the transmission shaft to the third-stage planetary gear set sun gear 6.1.

[0087] The control system sends a second gear shifting control command to the shift actuator of the shift mechanism 6. The shift actuator drives the gear sleeve 6.7 to slide along the central axis towards the second side under the thrust of the shift fork on the gear seat 6.7; after the gear sleeve 6.7 slides to the predetermined limit position, the second gear engagement tooth 6.9 on the gear sleeve 6.7 engages with the outer engagement tooth profile of the third-stage planetary gear sun gear 6.1.

[0088] Through the mechanical locking action of the gear sleeve 6.7, the sun gear 6.1 and the ring gear 6.4 of the third-stage planetary gear set are locked together in the direction of rotation to form a rigid transmission body, restricting the relative movement between the sun gear 6.1, the multiple planet gears 6.2 of the third-stage planetary gear set, and the ring gear 6.4 of the third-stage planetary gear set; the entire third-stage planetary gear set and the shifting mechanism 6 form a synchronized rotating body and rotate as a whole with the central axis of the system. Power is transmitted directly from the sun gear 6.1 of the third-stage planetary gear set to the rear without the meshing transmission of internal gears, eliminating the gear meshing loss inside the third-stage planetary gear set, so that the power of the engine 1 is directly transmitted to the planet carrier 6.3 of the third-stage planetary gear set at a speed ratio of 1:1.

[0089] Power is output from the third-stage planetary gear set planet carrier 6.3 and transmitted to the next stage, and finally distributed to the wheels through the main reduction gear and differential mechanism, i.e., the differential, to drive the vehicle.

[0090] See attached document Figure 10 When a vehicle starts, climbs a hill, or operates under low-speed, high-load conditions, the demand for driving torque is relatively high. To meet the torque requirements under these conditions, the hybrid powertrain system of this invention controls the third-stage planetary gear set and shift mechanism 6 to perform the first gear shift. In a specific embodiment of this invention, the specific control logic of this mode involves using the axial displacement of the gear sleeve 6.7 to lock and fix the third-stage planetary gear set ring gear 6.4 to the gearbox housing via the ring gear bracket 6.5. Under the mechanical constraint of the fixed ring gear, the third-stage planetary gear set exhibits a transmission characteristic of deceleration and torque amplification, thereby amplifying the power transmitted from the previous stage and outputting it to the main reduction and differential mechanisms.

[0091] The vehicle controller collects real-time signals from the vehicle's speed sensor and accelerator pedal opening. When it determines that the vehicle is in the starting phase, climbing a hill, or the current speed is below a preset low-speed shift boundary (set to a speed range of 0 km / h to 45 km / h), and the corresponding required torque exceeds a set upper limit threshold for direct drive torque (preferably set to 150 N·m), the vehicle controller generates a first gear shift control signal. The vehicle controller sends the control signal to the underlying execution unit of the shift mechanism, triggering the gear shift action. To ensure the stability of the control system and avoid frequent actuation of the shift mechanism near critical speeds, a shift hysteresis range is built into the control logic. By setting an overlap judgment difference of, for example, 3 km / h to 5 km / h above and below the shift critical boundary, dead zones in logic judgment caused by slight fluctuations in vehicle speed are eliminated.

[0092] After receiving the first gear shift control signal, the shift actuator energizes the internal electromagnetic shift valve or shift fork motor. The shift fork applies an axial force to the gear sleeve 6.7, driving it to slide along the central transmission axis towards the first side on the external spline of the gear seat 6.6. When the gear sleeve 6.7 slides to the predetermined first side limit position, the internal spline teeth of the gear sleeve 6.7 engage with the external spline teeth of the first gear engagement tooth 6.8, achieving a meshing connection.

[0093] The first gear engagement gear 6.8 is mechanically connected to the gear ring support 6.5, which in turn is rigidly connected to the third-stage planetary gear ring 6.4. Since the gear seat 6.6 is rigidly fixed to the gearbox housing via splines or fasteners, the gear sleeve 6.7 is always constrained by the circumferential rotation of the gear seat 6.6 during axial sliding. When the gear sleeve 6.7 engages with the first gear engagement gear 6.8, it restricts the rotational freedom of the gear ring support 6.5 to a relatively fixed state relative to the gearbox housing. The third-stage planetary gear ring 6.4 receives the engagement constraint from the gear sleeve 6.7 and the gear ring support 6.5, and is locked and fixed to the gearbox housing, in a circumferentially limited braking state.

[0094] Under the power output from the pre-stage power source, power is input to the third-stage planetary gear set sun gear 6.1, driving it to rotate at the input speed. Under the kinematic constraint of the third-stage planetary gear set ring gear 6.4 being locked and fixed, the rotational motion of the third-stage planetary gear set sun gear 6.1 drives multiple externally distributed third-stage planetary gear sets 6.2 to rotate and revolve within the locked third-stage planetary gear set ring gear 6.4.

[0095] The revolution of multiple third-stage planetary gears 6.2 drives the third-stage planetary carrier 6.3, which supports the planetary gears, to rotate in the same direction. According to the mechanical kinematic transmission ratio relationship of the planetary gear mechanism, that is, the speed ratio between the planetary carrier and the sun gear is constrained by the inherent ratio of the number of teeth on the sun gear to the number of teeth on the ring gear, and the transmission ratio is always greater than one, the rotational speed of the third-stage planetary carrier 6.3 is lower than the input speed of the sun gear 6.1, completing the mechanical transmission process of reducing speed and increasing torque. The power after reducing speed and amplifying torque is output from the third-stage planetary carrier 6.3, transmitted to the subsequent stages to the main reduction and differential mechanisms, and finally delivered to the wheels to support the vehicle's smooth driving under low-speed, high-torque conditions.

[0096] Under medium-to-high-speed cruising conditions where vehicle speeds are higher and the demand for driving torque is relatively lower, the series-parallel hybrid system controls the third-stage planetary gear set and shift mechanism 6 to perform the second gear shift. The specific control principle of this gear shift is to use the axial translation of the gear sleeve 6.7 to mechanically lock the two independent rotating components inside the third-stage planetary gear set. Due to the kinematic constraints of the mutual locking of the internal components, the third-stage planetary gear set loses its internal differential and deceleration effects, exhibiting the transmission characteristics of a direct drive, thereby transmitting the power input from the previous stage to the subsequent transmission system at a 1:1 speed ratio.

[0097] The vehicle controller monitors the speed signal collected by the vehicle speed sensor and the torque demand signal applied by the driver in real time. When it determines that the vehicle speed has reached the preset high-speed shift boundary, for example, the vehicle speed is within the range of 45km / h to 120km / h, and the current driving torque demand is less than the set downshift torque threshold, preferably set to less than 150N·m, the control system outputs a second gear shift command. The downshift torque threshold and vehicle speed boundary are obtained through calibration tests on a vehicle chassis dynamometer bench. To avoid frequent gear skipping oscillations in the control system caused by small fluctuations in vehicle speed or transient changes in the accelerator pedal, the control logic is set with a hysteresis protection range; when the vehicle speed decreases to the preset exit threshold, for example, below 40km / h, or the torque demand jumps to above 200N·m, the control system triggers the control process of exiting the second gear and jumping back to the first gear, thereby eliminating the dead zone phenomenon of algorithm control.

[0098] The shift actuator responds to the second gear shift command, driving the shift fork to overcome the resistance of the return assembly. The shift fork applies a thrust parallel to the central drive axis to the gear sleeve 6.7, driving the gear sleeve 6.7 to slide towards the second side on the external spline of the gear seat 6.6. When the gear sleeve 6.7 slides to the mechanical limit position on the second side, the inner spline teeth of the gear sleeve 6.7 engage with the outer ring engagement teeth of the second gear engagement tooth 6.9.

[0099] In the mechanical topology of the third-stage planetary gear set and shifting mechanism 6, the gear seat 6.6 is rigidly connected to the third-stage planetary gear set ring gear 6.4 via a mechanical fastening structure and rotates coaxially with the third-stage planetary gear set ring gear 6.4; while the second gear engagement tooth 6.9 is fixedly mounted on the extended shaft section of the third-stage planetary gear set sun gear 6.1. When the gear sleeve 6.7 bridging between the gear seat 6.6 and the second gear engagement tooth 6.9 and completing the engagement constraint, the third-stage planetary gear set ring gear 6.4 and the third-stage planetary gear set sun gear 6.1 are rigidly connected together in the circumferential rotation direction, and the relative speed difference between the two is limited by mechanical limiting constraints.

[0100] According to the three-component kinematic constraint mechanism of the planetary gear mechanism, when the rotational speeds of the sun gear 6.1 and the ring gear 6.4 of the third-stage planetary gear set are forced to be equal by the gear sleeve 6.7, the multiple planetary gears 6.2 of the third-stage planetary gear set mounted on the planet carrier 6.3 of the third-stage planetary gear set do not possess the kinematic conditions to generate relative rotation. Therefore, the multiple planetary gears 6.2 of the third-stage planetary gear set remain relatively stationary between the ring gear 6.4 and the sun gear 6.1 of the third-stage planetary gear set, restricting the relative meshing motion between the internal components of the third-stage planetary gear set. Under the action of external driving torque, the entire third-stage planetary gear set and the shifting mechanism 6 form a synchronous rotating body and rotate as a whole around the central axis of the transmission system.

[0101] The driving power input to the sun gear 6.1 of the third-stage planetary gear set does not undergo a reduction and meshing process between the planet gears and the sun gear and the ring gear. Instead, it is directly transmitted to the planet carrier 6.3 of the third-stage planetary gear set at a fixed 1:1 transmission ratio through the aforementioned synchronously rotating integrated mechanism. The planet carrier 6.3 of the third-stage planetary gear set, as the end-output component, delivers power to the main reduction and differential mechanisms to support the vehicle's driving needs under medium- and high-speed conditions. This physical switching of the transmission path reduces mechanical friction losses and oil churning resistance caused by gear meshing.

[0102] Working Principle: The hybrid power system of this invention uses a shared rotational axis to coaxially arrange the engine 1, first motor 2, first-stage planetary gear set 3, second motor 4, second-stage planetary gear set 5, third-stage planetary gear set, and shift mechanism 6. The vehicle controller controls the transmission system to switch between pure electric drive mode, hybrid drive mode, and engine direct drive mode by real-time acquisition of the power battery's charge status and the driver's pedal input signal. At the same time, it controls the shift mechanism 6 to axially shift between the first gear shift state and the second gear shift state, thereby changing the transmission ratio and realizing deceleration and torque increase or direct transmission. The power is finally transmitted to the wheels 11 through the main reduction and differential mechanism and the wheel-side planetary gear set reducers 10 on both sides to drive the vehicle under different operating conditions.

[0103] When the system meets the pure electric drive mode conditions, the vehicle controller keeps the engine 1 off to cut off its power output. The electrical energy output from the power battery is transmitted to the second motor 4 via the inverter, controlling the second motor 4 to enter electric operation and output drive torque. The rotor shaft of the second motor 4 drives the second-stage planetary gear set sun gear 5.1 to rotate. Since the second-stage planetary gear set ring gear 5.4 is fixedly connected to the gearbox housing, the rotation of the second-stage planetary gear set sun gear 5.1 drives multiple second-stage planetary gear set planet gears 5.2 to rotate and revolve inside the second-stage planetary gear set ring gear 5.4, thereby driving the second-stage planetary gear set planet carrier 5.3 to decelerate and increase torque. The second-stage planetary gear set planet carrier 5.3 transmits the drive torque to the third-stage planetary gear set sun gear 6.1. During this process, since the first-stage planetary gear ring 3.4 is coaxially fixed on the second-stage planetary gear sun gear 5.1, the power is input in reverse to the first-stage planetary gear ring 3.4. The first-stage planetary gear ring 3.4 rotates and drives multiple first-stage planetary gears 3.2 to rotate on the stationary first-stage planetary carrier 3.3, thereby overcoming the rotational inertia of the first motor 2 and driving the first-stage planetary gear sun gear 3.1 to rotate, so that the rotor of the first motor 2 follows and idles.

[0104] When the system meets the conditions for hybrid drive mode, the first motor 2 receives current input and enters electric operation. It transmits torque to the output shaft of the engine 1 via the first-stage planetary gear set 3 to increase its speed. Subsequently, the engine 1 ignites and outputs power, continuously inputting speed and torque to the first-stage planetary gear set carrier 3.3 of the first-stage planetary gear set 3. The power input from the engine 1 is split within the first-stage planetary gear set 3. The rotation of the first-stage planetary gear set carrier 3.3 drives multiple first-stage planetary gear set planetary gears 3.2 to rotate. The first motor 2 applies a reverse balancing torque through the first-stage planetary gear set sun gear 3.1 and enters power generation mode, converting a portion of the mechanical energy into electrical energy and transmitting it to the second motor 4. Another portion of the mechanical energy input from the engine 1 is transmitted to the first-stage planetary gear set ring gear 3.4 via multiple first-stage planetary gear set planetary gears 3.2. The mechanical power output from the first-stage planetary gear set ring gear 3.4 and the electric drive torque output from the second motor 4 after receiving electrical energy merge at the position of the second-stage planetary gear set sun gear 5.1, achieving coaxial mechanical superposition coupling of the two power sources. The coupled power is transmitted through the reduction and torque amplification transmission of the second-stage planetary gear set 5, and then from the planet carrier 5.3 of the second-stage planetary gear set to the sun gear 6.1 of the third-stage planetary gear set.

[0105] When the system meets the engine direct drive mode conditions, the vehicle controller activates the locking device corresponding to the first motor 2, restricting the rotor rotation of the first motor 2 through a mechanical locking pin or friction brake, causing the first-stage planetary gear set sun gear 3.1 to synchronously enter a locked and fixed state. The output shaft of the engine 1 continuously inputs power to the first-stage planetary gear set planet carrier 3.3 of the first-stage planetary gear set 3. Under the constraint of the first-stage planetary gear set sun gear 3.1 being locked and fixed, the rotational motion of the first-stage planetary gear set planet carrier 3.3 forces multiple first-stage planetary gear set planet gears 3.2 to revolve around the outside of the first-stage planetary gear set sun gear 3.1, and drives the first-stage planetary gear set ring gear 3.4 to rotate through mechanical tooth meshing, achieving speed-increasing transmission. The mechanical power output from the first-stage planetary gear set ring gear 3.4 is directly transmitted to the coaxially coupled second-stage planetary gear set sun gear 5.1, at which time the second motor 4 is in a zero-torque control state and rotates accordingly. The power input to the sun gear 5.1 of the second-stage planetary set is driven by the rotation and revolution of the second-stage planetary set 5 to drive the planet carrier 5.3 of the second-stage planetary set to decelerate and rotate, and then input to the sun gear 6.1 of the third-stage planetary set.

[0106] After power is input to the sun gear 6.1 of the third-stage planetary gear set, if the system controls the third-stage planetary gear set and the shift mechanism 6 to perform the first gear shift, the shift actuator drives the gear sleeve 6.7 to slide axially in the first direction on the gear seat 6.6, so that the gear sleeve 6.7 engages with the first gear engagement gear 6.8. The gear ring bracket 6.5 locks and fixes the third-stage planetary gear set gear ring 6.4 to the gearbox housing. The power input from the sun gear 6.1 of the third-stage planetary gear set drives multiple planet gears 6.2 of the third-stage planetary gear set to revolve inside the locked third-stage planetary gear set gear ring 6.4, driving the planet carrier 6.3 of the third-stage planetary gear set to perform deceleration transmission and increase torque. Power is output from the planet carrier 6.3 of the third-stage planetary gear set. If the system controls the third-stage planetary gear set and shifting mechanism 6 to perform the second gear shift, the shifting actuator drives the gear sleeve 6.7 to slide and translate on the gear seat 6.6 in the second direction, so that the gear sleeve 6.7 engages with the second gear engagement tooth 6.9, locking the sun gear 6.1 of the third-stage planetary gear set and the ring gear 6.4 of the third-stage planetary gear set together in the circumferential rotation direction, limiting the relative speed difference between them. At this time, the multiple planet gears 6.2 of the third-stage planetary gear set remain relatively stationary, and the entire third-stage planetary gear set and shifting mechanism 6 form a synchronous rotating body, and the power is directly transmitted to the planet carrier 6.3 of the third-stage planetary gear set and output. The power output from the third-stage planetary gear set planetary carrier 6.3 drives the driving bevel gear 7 to rotate, which in turn drives the driven bevel gear 8 to rotate. The driven bevel gear 8 drives the differential housing 9.1 and the inner planetary gear 9.2 to rotate. The planetary gear 9.2 distributes the power to the half-shaft gears 9.3 on both sides. The half-shaft gears 9.3 independently transmit the power to the corresponding wheel-side planetary gear set sun gear 10.1 and drive the wheel-side planetary gear set planetary gear 10.2 to rotate. Since the wheel-side planetary gear set ring gear 10.4 is fixedly connected to the axle, the multiple wheel-side planetary gear set planetary gears 10.2 revolve inside the wheel-side planetary gear set ring gear 10.4 and drive the wheel-side planetary gear set planetary carrier 10.3 to rotate. The wheel-side planetary gear set planetary carrier 10.3 ultimately drives the rigidly connected wheel 11 to rotate and move.

Claims

1. A series-parallel hybrid power system, characterized in that, include: An engine (1), a gearbox housing, and an axle are provided. The output end of the engine (1) is coaxially provided with a first-stage planetary gear set (3). The first-stage planetary gear set (3) is located inside the gearbox housing. A first motor (2) is provided on the side of the first-stage planetary gear set (3). The output end of the first motor (2) is connected to the first-stage planetary gear set (3). The output end of the first-stage planetary gear set (3) is coaxially coupled to a second-stage planetary gear set (5). A second motor (4) is connected to the inner side of the second-stage planetary gear set (5). The output end of the second-stage planetary gear set (5) is connected to the third-stage planetary gear set and the shifting mechanism (6), and the output end of the third-stage planetary gear set and the shifting mechanism (6) is connected to the main reduction gear and the differential mechanism.

2. The hybrid power system according to claim 1, characterized in that, The first-stage planetary gear set (3) includes a first-stage planetary gear set carrier (3.3), which is rigidly connected to the output shaft of the engine (1). A first-stage planetary gear set sun gear (3.1) is provided on the inner side of the first-stage planetary gear set carrier (3.3). The output shaft of the first motor (2) is connected to the first-stage planetary gear set sun gear (3.1). A plurality of first-stage planetary gear set planetary gears (3.2) are rotatably connected to the first-stage planetary gear set carrier (3.3). A first-stage planetary gear set ring gear (3.4) is meshed with the outer side of the plurality of first-stage planetary gear set planetary gears (3.2). The first-stage planetary gear set ring gear (3.4) is connected to the second-stage planetary gear set (5).

3. A series-parallel hybrid power system according to claim 2, characterized in that, The second-stage planetary gear set (5) includes a second-stage planetary gear set sun gear (5.1). The output ends of the first-stage planetary gear set ring gear (3.4) and the second motor (4) are coaxially coupled to the second-stage planetary gear set sun gear (5.1). Multiple second-stage planetary gear set planetary gears (5.2) are meshed on the outer side of the second-stage planetary gear set sun gear (5.1). A second-stage planetary gear set ring gear (5.4) is arranged around the multiple second-stage planetary gear set planetary gears (5.2). The second-stage planetary gear set ring gear (5.4) is fixedly connected to the gearbox housing. A second-stage planetary gear set planet carrier (5.3) is rotatably connected to the second-stage planetary gear set planetary gears (5.2). The second-stage planetary gear set planet carrier (5.3) is connected to the third-stage planetary gear set and the shifting mechanism (6).

4. A series-parallel hybrid power system according to claim 3, characterized in that, The third-stage planetary gear set and shifting mechanism (6) includes a third-stage planetary gear set sun gear (6.1), the end of the second-stage planetary gear set planet carrier (5.3) is fixedly connected to the third-stage planetary gear set sun gear (6.1), a plurality of third-stage planetary gear set planetary gears (6.2) are meshed on the outer side of the third-stage planetary gear set sun gear (6.1), a third-stage planetary gear set planet carrier (6.3) is rotatably connected to the plurality of third-stage planetary gear set planetary gears (6.2), the third-stage planetary gear set planet carrier (6.3) is connected to the main reduction and differential mechanism, a third-stage planetary gear set ring gear (6.4) is arranged around the plurality of third-stage planetary gear set planetary gears (6.2), and the third-stage planetary gear set ring gear (6.4) is connected to the shifting mechanism (6).

5. A series-parallel hybrid power system according to claim 4, characterized in that, The shifting mechanism (6) includes a gear ring bracket (6.5), which is connected between the third-stage planetary gear ring (6.4) and the gearbox housing. A gear seat (6.6) is provided inside the shifting mechanism. A gear sleeve (6.7) is slidably connected to the gear seat (6.6). A first gear engagement tooth (6.8) is provided on one side of the gear sleeve (6.7), which engages with the gear ring bracket (6.5). A second gear engagement tooth (6.9) is provided on the other side of the gear sleeve (6.7), which engages with the sun gear (6.1) of the third-stage planetary gear set.

6. A series-parallel hybrid power system according to claim 1, characterized in that, The main reduction and differential mechanism includes a driving bevel gear (7), which is rigidly connected to the output end of the third-stage planetary gear set and shifting mechanism (6). A driven bevel gear (8) is meshed on the outside of the driving bevel gear (7). A differential (9) is fixedly connected to the side of the driven bevel gear (8). A differential housing (9.1) is provided on the outside of the differential (9). The differential housing (9.1) is rigidly connected to the driven bevel gear (8). A planetary gear (9.2) is rotatably connected to the inside of the differential housing (9.1). Half-shaft gears (9.3) are meshed on both sides of the planetary gear (9.2).

7. A series-parallel hybrid power system according to claim 6, characterized in that, The output end of the half-shaft gear (9.3) is connected to a wheel-side planetary gear reducer (10). Each half-shaft gear (9.3) on both sides is provided with a wheel-side planetary gear reducer (10). The wheel-side planetary gear reducer (10) includes a wheel-side planetary gear sun gear (10.1). The half-shaft gear (9.3) is connected to the wheel-side planetary gear sun gear (10.1). Multiple wheel-side planetary gears (10.2) are meshed on the outer side of the wheel-side planetary gear sun gear (10.1). Wheel-side planetary gear rings (10.4) are meshed on the outer side of the multiple wheel-side planetary gears (10.2). The wheel-side planetary gear rings (10.4) are fixedly connected to the axle. Wheel-side planetary gear carriers (10.3) are rotatably connected to the wheel-side planetary gears (10.2). Wheel-side planetary gear carriers (10.3) are rigidly connected to the wheel (11).

8. A series-parallel hybrid power system according to claim 1, characterized in that, The engine (1), the first motor (2), the first-stage planetary gear set (3), the second motor (4), the second-stage planetary gear set (5), and the third-stage planetary gear set and shifting mechanism (6) share the same rotation center axis in spatial layout and are arranged coaxially.

9. A method for operating a series-parallel hybrid power system according to any one of claims 1-8, characterized in that, The following working modes are included: Pure electric drive mode: The engine (1) stops working, the second motor (4) outputs power to the second-stage planetary gear sun gear (5.1), the power is transmitted to the third-stage planetary gear sun gear (6.1) through the second-stage planetary gear carrier (5.3), the power is transmitted to the wheel (11) through the third-stage planetary gear and shifting mechanism (6) and the main reduction and differential mechanism, and the first motor (2) rotates in conjunction with the first-stage planetary gear ring (3.4); Hybrid drive mode: The engine (1) starts and drives the first-stage planetary gear carrier (3.3) to rotate. The first motor (2) rotates to generate electricity, and the electrical energy is transmitted to the second motor (4). The mechanical power output by the engine (1) is transmitted to the second-stage planetary gear sun gear (5.1) through the first-stage planetary gear ring (3.4). The second motor (4) outputs power to the second-stage planetary gear sun gear (5.1). The combined power is transmitted to the third-stage planetary gear sun gear (6.1) through the second-stage planetary gear carrier (5.3). The combined power is transmitted to the wheels (11) through the third-stage planetary gear and shifting mechanism (6) and the main reduction and differential mechanism. Engine direct drive mode: The first motor (2) is locked, the engine (1) is started and drives the first stage planetary gear carrier (3.3) to rotate. The power is transmitted sequentially through the first stage planetary gear ring (3.4), the second stage planetary gear sun gear (5.1) and the second stage planetary gear carrier (5.3) to the third stage planetary gear sun gear (6.1). The power is transmitted to the wheels (11) through the third stage planetary gear and shifting mechanism (6) in the second gear position and the main reduction and differential mechanism.

10. The operating method of a series-parallel hybrid power system according to claim 9, characterized in that, The third-stage planetary gear set and shifting mechanism (6) specifically performs the following gear shifting steps: First gear shift: Axial movement of the gear sleeve (6.7), the gear sleeve (6.7) engages with the first gear engagement gear (6.8), the gear ring bracket (6.5) locks the third-stage planetary gear ring (6.4), power is input from the third-stage planetary sun gear (6.1), transmitted through the third-stage planetary gear (6.2) to the third-stage planetary carrier (6.3) and then to the main reduction and differential mechanism; Second gear shift: Axial movement of the gear sleeve (6.7), the gear sleeve (6.7) engages with the second gear engagement gear (6.9), the gear sleeve (6.7) locks the third-stage planetary set sun gear (6.1) and the third-stage planetary set ring gear (6.4), the third-stage planetary set and the shifting mechanism (6) rotate as a whole, and the power is directly transmitted from the third-stage planetary set sun gear (6.1) to the third-stage planetary set planet carrier (6.3) and then to the main reduction and differential mechanism.

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