A kind of electric vehicle speed changer and speed change method thereof

Abstract

The invention discloses an electric vehicle transmission and a transmission method thereof, which includes a hydraulic torque converter with a locking function, an oil pump, an oil pump motor, a controller, a reduction mechanism, and a differential. The hydraulic torque converter includes a pump wheel, a turbine, an input shaft, an output shaft and other parts. The drive motor is connected to the pump wheel through the input shaft, and the turbine is connected to the output shaft. In most cases of the electric vehicle transmission, the hydraulic torque converter is in a locked state. When the motor's torque passes through the hydraulic torque converter, it is directly transmitted, and the transmission efficiency is high; when the electric vehicle is climbing at low speed or accelerating rapidly, When starting, the hydraulic torque converter is controlled to be in an unlocked state. The hydraulic torque converter has a hydraulic torque converter function, which increases the driving torque, improves the climbing performance and acceleration performance, and prevents the motor from working in a stalled state. The electric vehicle transmission of the invention has a simple structure and is convenient to control, can improve the climbing performance and acceleration performance of the electric vehicle, and enhance the reliability of the vehicle.

Description

technical field [0001] The invention relates to an automobile transmission and a speed changing method, in particular to a transmission suitable for pure electric vehicles and a speed changing method thereof. Background technique [0002] The development of energy-saving and new energy vehicles has become an inevitable choice for my country's energy strategy. The current focus is to promote the industrialization of pure electric vehicles and plug-in hybrid vehicles, popularize non-plug-in hybrid vehicles and energy-saving internal combustion engine vehicles, and upgrade my country's automobile industry. overall technical level. [0003] At present, there are mainly the following schemes for the speed change of electric vehicles. The first option is to use a fixed reduction ratio; the second option is to use a two-speed transmission; the third option is to use the transmission of a traditional fuel vehicle for speed change. Because the motor itself has the characteristics of...

AI Technical Summary

Problems solved by technology

[0006] The deficiencies of this electric vehicle transmission mainly include the following two points: first, the motor rotor speed changes greatly when shifting gears, and the moment of inertia of the rotor also changes greatly, resulting in greater wear and tear on the friction plates of the brake and clutch; second, starting When the motor is working in a stalled state, it is easy to cause the motor to be burned

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