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

Abstract

The invention discloses an electric automobile speed changer and a speed changing method thereof. The electric automobile speed changer comprises a hydraulic torque converter with the locking function, an oil pump, an oil pump motor, a controller, a speed reducing mechanism and a differential mechanism. The hydraulic torque converter comprises a pump wheel, a worm wheel, an input shaft, an output shaft and the like, a driving motor is connected with the pump wheel through the input shaft, and the worm wheel is connected with the output shaft. In most cases, the hydraulic torque converter is located in the locking state, the torque of the motor is in direction transmission when passing through the hydraulic torque converter, and transmission efficiency is high. When an electric automobile is in low-speed climbing or rapid acceleration start state, the hydraulic torque converter is controlled to be in an unlocking state, the hydraulic torque converter is provided with hydraulic torque changing function, the torque is driven to be improved, climbing performance and acceleration performance are improved simultaneously, and lock-rotor state of the motor is avoided. The electric automobile speed changer is simple in structure and convenient to control, can improve the climbing performance and the acceleration performance of the electric automobile, and enhances reliably of the automobile.

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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