Double planetary gear train type stepless automatic speed change mechanism

Abstract

A double planetary gear train type stepless automatic speed change mechanism comprises an input planetary gear train and an output planetary gear train. Both the planetary gear trains comprise sun gears, planetary gears, outer gear rings and planetary carriers. The two sun gears are installed on a center shaft, the center shaft is installed on a machine shell, input gears are meshed with the sun gear in the input train, the sun gear of the output train is meshed with output gears, an input shaft is installed on the machine shell, and an output shaft is installed on the machine shell through a one-way clutch. The two planetary carriers are fixedly connected, the two gear rings are fixedly connected, and the gear ratios of the gear rings to the sun gears in the two planetary gear trains are not equal. According to the double planetary gear train type stepless automatic speed change mechanism, an internal power circulation flow which is only affected by the external rotation angular speed or the torque is established beside a main power circulation flow, the suitable output torque and the suitable rotation angular speed can be acquired by changing the internal circulation flow, the automatic stepless speed change function can be achieved, a hydraulic mechanism is not needed, and the double planetary gear train type stepless automatic speed change mechanism has relatively high economy and wide practicality.

Description

technical field [0001] The invention relates to a speed change mechanism, in particular to a stepless automatic speed change mechanism including a double planetary gear train. Background technique [0002] The speed change mechanism is a transmission device that enables the output shaft to obtain different speeds or torques under the condition that the speed or torque of the input shaft is constant, that is, to meet the needs of different working conditions through variable speed or torque, and is widely used in various occasions . [0003] Taking the automotive field as an example, in order to meet the different requirements for driving wheel traction and vehicle speed under different driving conditions such as starting, accelerating, driving and overcoming various road obstruction lights, a transmission is usually installed between the engine and the drive axle. With the development of the automobile industry, automobile transmissions have experienced the development from...

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Problems solved by technology

With the development of the automobile industry, automobile transmissions have experienced the development from non-automatic transmission mechanisms to automatic transmissions, from stepped to stepless, such as traditional pulley transmission mechanisms, gear transmission mechanisms, etc. The single transmission ratio of such transmission mechanisms is There is a variable speed, but the manufacturing cost is low, and the process is relatively mature; another example is the torque-based hydraulic automatic transmission (AT), which can realize stepless speed change independently, but the mechanism is complicated, the process is complicated, the manufacturing cost is high, and due to the hydraulic coupling During the use of the converter, part of the energy output by the car is converted into oil temperature, so the economy is relatively poor

In addition to the above, the more mature automatic transmissions in the world currently include mechanical continuously variable automatic transmission (CVT) and electronically controlled mechanical automatic transmission (AMT). The former is based on a pair of V-shaped pulleys, steel belts and a set of hydraulic and computer A micro-control system is used to realize stepless automatic transmission. The transmission has high technical content, complicated manufacture, high cost, relatively short service life of the transmission belt, and high maintenance cost. Due to various technical limitations such as material properties, it is currently mainly limited to It is used in low-power vehicles; the latter is based on traditional transmissions and computer-controlled automatic operating mechanisms to achieve stepped and automatic transmission. Although it is easy to manufacture and low in cost, its shift performance is poor, and there is a sense of frustration when shifting gears. The sense of frustration is particularly obvious. In addition, the transmission can only realize stepped speed change, but not infinitely variable speed change, and external intervention is required

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