Power transmission mode of new energy vehicles

The transmission system of traditional internal combustion engine-driven vehicles consists of clutch, transmission, transmission shaft, main reducer, differential and half shaft. The transmission system ensures that the vehicle has the necessary traction and speed under various driving conditions, ensures the coordinated change of traction and speed, and makes the vehicle have good power and fuel economy. It also ensures that the car can reverse, the left and right driving wheels can meet the differential requirements, and the power transmission can be smoothly combined or completely separated as needed.

These components are not only light in weight, which makes the structure of the vehicle more complicated, but also have problems of regular maintenance and failure rate. For new energy vehicles, the design of transmission system is more flexible. Judging from its evolution process, there are the following forms.

1, the transmission system is similar to an internal combustion engine car.

There are also clutches, gearboxes and differentials.

2, the clutch is omitted, and the driving motor, the constant speed ratio reducer and the differential are integrated.

3. The hub motor is integrated with the wheel.

Hub motor

The development of hub motor has solved the problem of complex structure of traditional transmission system. In addition to the simpler structure, the vehicle driven by hub motor can also obtain better space utilization and higher transmission efficiency.

According to the rotor type of the motor, the in-wheel motor drive system is mainly divided into two structural types: inner rotor type and outer rotor type.

The outer rotor type adopts a low-speed outer rotor motor, and the maximum speed of the motor is 1000- 1500RPM. Without a speed reducer, the speed of the wheel is the same as that of the motor. The low-speed external rotor motor is adopted, and the external rotor is installed on the rim of the wheel. The motor speed is equal to the wheel speed, and there is no need for a deceleration device.

Inner rotor type, using high-speed inner rotor motor, equipped with fixed transmission ratio star reducer, also known as wheel reducer, in order to obtain higher power density, the motor speed can be as high as 10000RPM. The speed ratio of the selected planetary gear transmission mechanism is 10: 1, and the speed range of the wheels is 0- 1000RPM. With the appearance of more compact planetary gear reducer, the inner rotor hub motor is more competitive than the low-speed outer rotor motor in power density.