Speed change mechanism of automatic two-gear transmission

Abstract

The invention provides a speed change mechanism of an automatic two-gear transmission. The speed change mechanism comprises a shell, a planetary gear system, a brake hub, a brake shoe assembly, a brake belt, a turbo-worm mechanism, a gear-shifting motor and a differential mechanism. The planetary gear system comprises a sun wheel, a compound planetary gear, an inner gear ring and a planetary carrier shaft. The sun wheel serves as the power input end. The sun wheel is connected with the planetary carrier shaft through the compound planetary gear, and meanwhile the sun wheel is connected with the inner gear ring in an engaged mode through the compound planetary gear. The planetary carrier shaft is sleeved with the brake hub. The planetary carrier shaft is sleeved with the brake shoe assembly through bearings. The two ends of the brake belt are connected with the shell and the turbo-worm mechanism respectively. The turbo-worm mechanism is driven by the gear-shifting motor to rotate. A gear set is arranged on the planetary carrier shaft. The differential mechanism is connected with the planetary carrier shaft in an engaged mode through the gear set. By means of the speed change mechanism of the automatic two-gear transmission, low-speed climbing performance and high-speed driving performance can be given into consideration for a pure electric vehicle, and the speed change mechanism has the advantages of being simple in structure, low in cost, high in transferring efficiency and the like.

Description

technical field [0001] The invention relates to the field of transmission devices for electric vehicles, in particular to a transmission mechanism for a two-speed automatic transmission. Background technique [0002] A pure electric vehicle (Battery Electric Vehicle, referred to as BEV) refers to a clean energy vehicle driven by an on-board power supply and driven by a motor. This type of vehicle is of great significance to protecting the environment and saving energy. [0003] Existing pure electric vehicles generally use a reduction gear with a single speed ratio. When the vehicle starts or climbs a slope, the power output by the drive motor must go through a large reduction ratio to obtain enough driving force to drive the vehicle, while at high speed, the vehicle needs a small reduction ratio to make the vehicle reach the maximum speed Require. Since there are various working conditions during the driving process of the vehicle, it is necessary to ensure sufficient dri...

AI Technical Summary

Problems solved by technology

The selection of the speed ratio of the single speed ratio reduction device is a trade-off between the above two working conditions. Although the drive motor itself has a certain speed regulation function, it is difficult to make the vehicle meet the performance requirements of low-speed climbing and high-speed driving at the same time.

In addition, when a vehicle equipped with a reduction gear with a single speed ratio is started or working at the highest speed, the drive motor is in a low-efficiency range, which has an adverse effect on the cruising range and life of the battery.

[0004] The existing AMT gearbox needs to cut off the power through the clutch when shifting gears, and the synchronizer is driven by the shift motor, which is difficult to control; the existing planetary gear AT gearbox uses a wet clutch to shift gears, which needs to be matched with a complex hydraulic system , the transmission efficiency is low, and the cost is high; the existing dual-clutch gearbox uses a wet clutch or a dry clutch to shift gears, and the control system is complex and costly

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