The compound planetary gear mechanism in the gear transmission system of hybrid electric vehicle is the key of the compound power shunting technology of hybrid electric vehicle. In order to make the power of the engine transmitted to the driving vehicle in two forms, one part is in the form of mechanical path and the other part is in the form of electric power, so as to realize the decoupling of engine speed and vehicle speed, so as to optimize the working state of the engine, Finally, the whole power system can achieve good fuel economy.
However, the traditional Ravigneaux planetary row (as shown in Figure 1) can not well meet the working requirements of the power shunt mechanism, so it is necessary to develop a new type of composite planetary row mechanism that can meet the working requirements (as shown in Figure 2). Compared with the traditional ravigneau X-type planetary arrangement mechanism, the basic structure of the composite planetary arrangement mechanism is similar, but the transmission ratio of the single planetary arrangement of the new composite planetary arrangement mechanism is increased. On the one hand, the engine can be started as long as the motor E1 has small torque capacity, on the other hand, its speed range is also larger, so the volume of the motor E1 is smaller, the manufacturing cost is reduced, and the structure is more compact; The transmission ratio of the double planetary row of the new composite planetary row mechanism is reduced, which increases the torque of the motor E2, so that the motor E2 can better play the role of power assistance, and avoids the premature entry of the engine into the power split driving mode due to the speed limit of the E2 motor itself in the pure electric working mode, resulting in the reduction of transmission efficiency in the system.
In Figures 1 and 2, ice is an engine; E1 is a small motor; E2 is large motor; S1 and S2 are solar wheels; C is planet carrier; R is the ring gear. The gear transmission system of the hybrid electric vehicle takes the engine and large and small motors as the power source of the system.