In order to meet the requirements of the power split working mode, the engine ice is connected to the planet carrier, the small motor E1 is connected to the small sun gear S1, the large motor E2 is connected to the large sun gear S2, and the ring gear R is used as the output shaft to transmit the power to the large and small gears of the reducer, then to the differential, and finally drive the vehicle through the half shaft, as shown in the figure.
The hybrid electric vehicle studied has four operation modes: pure electric operation mode, hybrid drive mode, braking energy recovery mode and parking charging mode. As shown in the figure, in the pure electric working mode, the brake 1 connected to the planet carrier locks the engine so that it cannot generate power. The large motor E2 provides power (the small motor E1 plays an auxiliary role) to drive the wheels. The energy transmission path is: large motor E2 → large sun gear S2 → asteroid gear P2 → large planet gear P1 → ring gear R → output gear → reduction gear mechanism → differential → wheel; The hybrid drive mode is divided into two modes: low-speed mode and medium high-speed mode. In the low-speed mode, the engine ice and the large motor E2 together provide power to drive the vehicle. The small motor E1 is in the power generation state, and the engine drives the small motor E1 to charge the battery at the same time; In the medium and high speed mode, the brake 2 connected to the small motor shaft locks the small motor to avoid the energy loss of the small motor E1. At the same time, the large motor E2 charges the battery, and its energy transmission path is: large motor E2 → large sun gear S2 → asteroid gear P2 → large planet gear P1 → ring gear R → output gear → reduction gear mechanism → differential → wheel; Engine ice → planet carrier C → large planet gear P1 → ring gear R → output gear → reduction gear unit → differential → wheel; Engine ice → planet carrier C → large planet gear P1 → small sun gear S1 → small motor E1 → battery; In the braking energy recovery mode, the engine stops fuel injection, and the large and small motors absorb braking energy to charge the battery; In the parking charging mode, that is, in the vehicle stop mode, the small motor E1 starts the engine and locks the output shaft of the gear ring, so that the large and small motors are in the power generation state to charge the battery.
Among the four working modes, the hybrid drive mode is the most commonly used mode, and the other three working modes can be considered as the special working conditions of the hybrid drive mode. Therefore, the research on the vibration and noise of the gear transmission system in the power system is carried out in the hybrid drive mode, the appropriate engine parameters and the parameters of large and small motors are selected, and the natural frequency of the gear transmission system is calculated by using simulationx software, By changing the relevant parameters, the natural frequency of the system can effectively avoid the meshing frequency within the working speed range of hybrid electric vehicle, so as to avoid resonance. The vibration characteristics of the hybrid transmission system are improved.