Electro-hydraulic power coupling device based on double planetary row

Abstract

An electromechanical-hydraulic coupling device based on a dual planetary gear set belongs to the field of hybrid power transmission technology. The device includes a dual planetary gear set coupling mechanism, a control motor, a drive motor, a hydraulic pump / motor, high and low pressure accumulators, hydraulic valves, a flywheel, and a clutch and brake assembly. The dual planetary gear set adopts a front and rear planetary carrier shared topology. The front sun gear connects to the flywheel, and the ring gear connects to the hydraulic pump / motor. The rear sun gear connects to the control motor, and the ring gear connects to the drive motor. Both planetary carriers jointly output power to the drive axle. The device can automatically switch between five modes according to operating conditions: pure electric drive, hydraulic drive, flywheel drive, electromechanical-hydraulic combined drive, and staged braking energy recovery. It integrates the advantages of high energy density of electric power, low-speed high torque of hydraulic power, and high power density of flywheel power, reducing the peak torque of the main drive motor, improving start-up smoothness, and achieving multi-stage efficient braking energy recovery. This solves the problems of insufficient power and single energy recovery in traditional engineering vehicle hybrid power systems.

Description

Technical Field This invention relates to the field of hybrid power transmission technology for engineering vehicles, specifically to an electromechanical-hydraulic coupling device based on a dual planetary gear set. Background Technology Heavy-duty engineering vehicles are characterized by frequent starts, large load fluctuations, numerous rapid acceleration and braking conditions, and complex operating environments. This places high demands on the power density, energy density, smoothness, and energy recovery efficiency of the power system. In the field of engineering vehicle power transmission, traditional fuel-powered systems suffer from high fuel consumption, significant exhaust emissions, and low efficiency at low speeds, making them unsuitable for the green and energy-saving development needs under the "dual carbon" goal. While pure electric engineering vehicles, using batteries as the sole energy source, offer the advantage of zero emissions, they also have significant technical shortcomings: the power density of the batteries is relatively low, failing to meet the instantaneous high-power output demands of vehicle start-up, hill climbing, and heavy-load operations; continuous high-current discharge significantly reduces battery charging and discharging efficiency and cycle life; the drive motor is prone to overheating and a sudden drop in efficiency under low-speed, high-load conditions, resulting in poor vehicle start-up smoothness; and braking energy recovery relies solely on the motor, with a single recovery method and insufficient instantaneous feedback capability, leading to a significant waste of braking energy and low overall vehicle energy utilization. Existing hybrid technologies mostly employ single coupling forms such as electromechanical coupling or hydraulic-mechanical coupling: electromechanical coupling systems rely on the collaboration of the motor and engine, achieving high energy density, but lack a high-power-density buffer unit, failing to mitigate instantaneous power surges; hydraulic-mechanical coupling systems utilize hydraulics for high-torque start-up and energy recovery, but hydraulic systems have low energy density and poor long-term driving range; flywheel energy storage systems, while possessing advantages such as instantaneous high power density and fast response, have limited energy storage capacity for a single flywheel, unable to meet the continuous driving needs of the vehicle, serving only as an auxiliary unit and unable to independently support the operation of the entire vehicle. Therefore, developing a novel power unit integrating electric, hydraulic, and flywheel power sources, and achieving efficient power coupling and multi-mode intelligent switching through a dual planetary gear set, has become a key technical problem urgently needing to be solved in the field of hybrid power for engineering vehicles. Summary of the Invention To address the shortcomings of the existing technology, this invention provides an electromechanical-hydraulic coupling device based on a dual planetary gear set. By using a flywheel and hydraulic pressure as auxiliary power sources for the vehicle, and leveraging the high power density and low-speed, high-torque characteristics of the hydraulic system, it can be adapted to heavy-load starts in engineering vehicles, avoiding low-speed inefficiency and overheating of the drive motor. Furthermore, the fast response speed and instantaneous high-power release of the flywheel reduce the vehicle's power requirements for the motor and battery, avoiding high-current charging and discharging of the battery under sudden load changes, improving the efficiency of the onboard energy power system, and extending its service life. The technical solution of the present invention is: to provide an electromechanical-hydraulic coupling device based on a double planetary gear set, including a double planetary gear set coupling mechanism, a drive motor, a control motor, a hydraulic pump / motor, a high-pressure accumulator, a low-pressure accumulator, a three-position four-way directional valve, a pressure sensor, a flywheel, a clutch assembly, a brake assembly, a drive axle, and wheels. The high-voltage accumulator and the low-voltage accumulator are connected to the hydraulic pump / motor through a three-position four-way directional valve to form a hydraulic power system. The hydraulic pump / motor is connected to the front planetary gear ring via clutch 1 and gear. The flywheel is connected to the sun gear of the front planetary gear set via clutch 2 and gear 3. The drive motor is connected to the rear planetary gear ring via clutch 3 and gear; The control motor is connected to the sun gear of the rear planetary gear set via gears; The front and rear planetary gear sets together form a dual planetary gear set coupling mechanism. The front and rear planetary gear sets are rigidly connected through a planet carrier, serving as the unified power output end of the device and connected to the drive axle.

[0001] The advantages of this invention are: 1. This invention designs an electromechanical-hydraulic coupling device based on a double planetary gear set, enabling hydraulic assisted drive during vehicle start-up. Clutches 1, 3, and 4 engage to transmit hydraulic power to the drive shaft; clutch 2 disengages to disconnect the flywheel power; brake 1 disengages, brake 2 engages to lock the front planetary gear set sun gear, and brake 3 engages to lock the rear planetary gear set sun gear. With the reversing valve in the right position, hydraulic oil flows from the high-pressure accumulator through a hydraulic pump / motor to the low-pressure accumulator, which functions as a hydraulic motor. Power travels from the high-pressure accumulator through the motor, left-side ring gear, planetary gears, and planetary carrier to the drive axle, driving the vehicle to start and accelerate. 2. This invention designs an electromechanical-hydraulic coupling device based on a double planetary gear set, enabling pure electric drive when the vehicle is traveling at a constant speed and under a light load. Clutches 1 and 2 disengage, disconnecting the hydraulic power system from the flywheel; clutches 3 and 4 engage, allowing power to be transmitted to the drive shaft; brake 1 engages to lock the front planetary gear set ring gear; brake 3 disengages. The drive motor drives the rear planetary gear set ring gear, and the control motor drives the rear planetary gear set sun gear. The two are coupled through planetary gears, outputting power to the drive axle and propelling the vehicle forward. 3. This invention designs an electromechanical-hydraulic coupling device based on a double planetary gear set, which allows for flywheel-assisted drive when the vehicle is accelerating and under heavy load. Clutch 1 disengages, disconnecting the hydraulic power system; clutches 2, 3, and 4 engage, allowing flywheel power to be transmitted to the drive shaft; brake 1 engages to lock the front planetary gear set ring gear; brakes 2 and 3 disengage, allowing the drive motor and control motor to operate normally. The flywheel power travels through clutch 2, the front planetary gear set sun gear, and the front planetary gear set planet carrier to the output shaft, working together with the rear planetary gear set electro-hydraulic system to drive the vehicle's acceleration. 4. This invention designs an electromechanical-hydraulic coupling device based on a double planetary gear set, enabling combined electromechanical-hydraulic drive under heavy-load climbing conditions. Clutches 1 and 2 engage, and brakes 1 and 2 disengage, allowing the flywheel and hydraulic power system to output power. The hydraulic power and flywheel power are coupled at the planetary carrier of the front planetary gear set, achieving positive power superposition. When the power required by the vehicle exceeds the power output by the hydraulic system and flywheel, the right-side electric power system provides power compensation. 5. This invention designs an electromechanical-hydraulic coupling device based on a double planetary gear set, enabling graded braking energy recovery during vehicle braking. The energy recovery mode adaptively switches according to braking intensity. During light braking, clutches 1 and 2 disengage, clutches 3 and 4 engage, brakes 1 and 3 lock, and the drive motor operates as a generator, converting braking kinetic energy into electrical energy for storage and recovery. During moderate braking, clutches 2, 3, and 4 engage, and brakes 1 and 3 disengage. The flywheel preferentially absorbs instantaneous braking kinetic energy, and the remaining braking energy is then converted into hydraulic energy and stored in a high-pressure accumulator via a hydraulic pump / motor. During heavy braking, after the recovery capacity of the motor, flywheel, and hydraulic system reaches its limit, mechanical braking intervenes to supplement the braking force. Attached Figure Description

[0002] Figure 1 This is a configuration diagram of an electromechanical-hydraulic multi-source power coupling device based on a double planetary gear setter. In the diagram: 1. Low-pressure accumulator, 2. High-pressure accumulator, 3. Pressure sensor, 4. Three-position four-way directional valve, 5. Hydraulic pump / motor, 6. Clutch 1, 7. Brake 1, 8. Front planetary carrier, 9. Front ring gear, 10. Front planetary gear, 11. Front sun gear, 12. Brake 2, 13. Clutch 2, 14. Flywheel, 15. Rear planetary gear, 16. Clutch 3, 17. Drive motor, 18. Brake 3, 19. Clutch 4, 20. Control motor, 21. Wheel, 22. Drive axle. Detailed Implementation

[0003] The invention will now be further described with reference to the accompanying drawings. Figure 1 This is a schematic diagram of a double planetary gear electro-hydraulic coupling device, including a double planetary gear coupling mechanism, a drive motor, a control motor, a hydraulic pump / motor, a high-pressure accumulator, a low-pressure accumulator, a three-position four-way directional valve, a pressure sensor, a flywheel, a clutch assembly, a brake assembly, a drive axle, and wheels. The high-voltage accumulator and the low-voltage accumulator are connected to the hydraulic pump / motor through a three-position four-way directional valve to form a hydraulic power system. The hydraulic pump / motor is connected to the front planetary gear ring via clutch 1 and gear. The flywheel is connected to the sun gear of the front planetary gear set via clutch 2 and gear 3. The drive motor is connected to the rear planetary gear ring via clutch 3 and gear; The control motor is connected to the sun gear of the rear planetary gear set via gears; The front and rear planetary gear sets together form a dual planetary gear set coupling mechanism. The front and rear planetary gear sets are rigidly connected through a planet carrier, serving as the unified power output end of the device and connected to the drive axle.

Claims

1. An electromechanical-hydraulic coupling device based on a double planetary gear setter, characterized in that, It includes a double planetary gear coupling mechanism, an electric power system, a hydraulic power system, a flywheel power system, a clutch assembly, and a brake assembly; The dual planetary gear coupling mechanism consists of a front planetary gear and a rear planetary gear. The planet carriers of the front planetary gear and the rear planetary gear are rigidly connected to form a unified power output end. The electric power system includes a drive motor and a control motor. The drive motor is connected to the ring gear of the rear planetary gear set, and the control motor is connected to the sun gear of the rear planetary gear set. The hydraulic power system includes a hydraulic pump / motor, a high-pressure accumulator, a low-pressure accumulator, and a three-position four-way directional valve. The hydraulic pump / motor is connected to the gear ring of the front planetary gear. The flywheel of the flywheel power system is connected to the sun gear of the front planetary gear set.

2. The electromechanical-hydraulic coupling device based on a double planetary gearbox according to claim 1, characterized in that, The clutch assembly includes clutch 1, clutch 2, clutch 3, and clutch 4; clutch 1 is used to control the power connection between the hydraulic pump / motor and the front planetary gear ring gear, clutch 2 is used to control the power connection between the flywheel and the front planetary gear sun gear, clutch 3 is used to control the power connection between the drive motor and the rear planetary gear ring gear, and clutch 4 is used to control the power connection between the planetary carrier and the drive axle.

3. The electromechanical-hydraulic coupling device based on a double planetary gear set according to claim 1, characterized in that, The brake assembly includes brake 1, brake 2, and brake 3; brake 1 is used to lock the front planetary gear ring gear, brake 2 is used to lock the front planetary gear sun gear, and brake 3 is used to lock the rear planetary gear sun gear.

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