Da Tong Qin

Thermal Network Model for Temperature Prediction in Planetary Gear Trains

Their high-power-density design combined with their limited space make planetary gear trains often high power losses difficult to dissipate to the surround in time. The thermal network model for temperature prediction in planetary gear trains has been proposed. According to the principle of the conservation of energy, the thermal network model have been built and the model have been employed to analyze the transient temperature of the three stage 2K-H planetary gear trains used in Φ6.3m earth pressure balance(EPB) shield machine in series. The computed temperature results of the proposed TNM were in very good agreement with experimental measurements. It has been shown that this method is capable of performing temperature analysis. The results stemmed from the TNM have been shown that the temperature rise of the sun gears is quicker than the other parts and the PGT doesn’t reach thermal balance after the oil temperature reached 90 degrees, so the cooling system should be compelled.

Intelligent Correction of Shift Schedule for Dual Clutch Transmissions Based on Different Driving Conditions

This paper focuses on intelligent correction of shift schedule for dual clutch transmissions based on different driving conditions. The problem of standard shift schedule has been presented, and the strategy has also been proposed to avoid shift hunting and unexpected shift. The driver’s intention and driving environment have been unified recognized as different driving conditions. A fuzzy logic technology has been used in driver’s attention recognition based on the throttle opening and its derivative. The standard shift schedule has been intelligently corrected at different driving condition separately. An algorithm based on correction coefficient of throttle opening and vehicle speed is proposed for intelligent correction. The corrected shift schedule can be directly used in real time shift control with suitable correction coefficient.

Investigation on the Transmission Efficiency of the Planetary Gear Train

A model for the transmission efficiency of the planetary gear train has been proposed based on the principle of energy. The network topology for the planetary gear train is established with the graph theory by substitution the net nodes for the parts. According to the principle of conservation of energy, the interaction model of the energy transfer of the gear train is built by the way of integration the energy transfer equations between the nodes. With the investigation on the power losses, the transmission efficiency of planetary gear train can be calculated.

Effects of Gear Manufacturing Error on the Dynamic Characteristics of Planetary Gear Transmission System of Wind Turbine

The effects of gear manufacturing error on the dynamic characteristics of planetary gear transmission system of wind turbine are studied in this paper. Firstly, the static transmission error combined with manufacturing error of the gear is deduced. Then, the nonlinear dynamic model of planetary gear transmission system of wind turbine is set up with the consideration of time-varying mesh stiffness, backlash and manufacturing error. Finally, the statistical characteristics of Vibration displacement response process of each component of planetary gear transmission system are obtained by simulation analysis of the planetary gear system of 1.5MW Semi-direct drive wind turbine with the consideration of the torque fluctuation caused by wind speed. The research results lay a foundation for reliability design and optimizing of gear transmission system of wind turbine.

Coordinated Torque Control for Mode-Switch between Motor and Engine Driving in Heavy Hybrid Electric Vehicle

Aiming the vehicle ride performance, the process of driving mode-switch for a heavy hybrid power system and parameter changes among the engine, motor, clutch and transmission during the Mode-Switch process between Motor and Engine Driving were analyzed. The coordinated torque control strategy was established for Mode-Switch between motor and engine driving. The heavy hybrid electric vehicle simulation model was developed based on the strategy. The performance for the mode-switch process between motor and engine driving was simulated and analyzed. The results show that introducing the coordinated control strategy reduces the torque fluctuation during the driving-mode-switch process and improves the vehicle drivability.

Research on the Dynamics of the Double Helical Gear Transmission

Against the transmission characteristics of the double helical gear pair, considering the time-varying mesh stiffness, the bearing radial and axial stiffness, the tensile and compressive stiffness of the transmission shaft, the bending stiffness of that, error excitations, and corresponding dampings, a double helical gear pair bending-torsion-axis coupling dynamic model was established by using the lumped parameter method based on the gear meshing theory and Lagrange equations. Based on the model, the dynamic response of double helical gear pair was solved, and taking the right side of helical gear as an example, the frequency spectrum characteristics of dynamic meshing force of the right side of helical gear were mainly analyzed. This research establishes the foundation for dynamic performance optimizations and reliability designs of the double helical gear pair transmission system in the future.

Design and Application Analysis of Hybrid Coupling System Based on CVT

To improve the power performance and fuel economy of hybrid electric vehicle, a design idea of hybrid coupling system that combines power coupling function of planetary differential and continuous ratio regulating characteristics of continuously variable transmission is proposed. Four designs of the coupling system that compact and operating mode is complete relatively are identified through using the method of lever analogy. The paper analyzes varieties of operating modes and power transfer lines of new type of coupling system in different vehicle conditions, such as normal travel, astern driving, vehicle start, engine start, parking generation, decelerate/brake, etc. Application and superiority of the four schemes of the coupling system applied to HEV are analyzed at last.

Dynamic Modeling of Multi-Stage Planetary Gears Coupled with Bearings in Housing

This work develops an analytical model of multi-stages planetary gear transmission (PGT) coupled with bearings in housing based on analyzing the displacement relationships of gearing system. The model adopts three planar degree-of-freedom for each of the central components, and the rotational degree-of-freedom for the planets of each stage. Considering the gyroscopic effects, the modified transverse-torsional model is established in the rotating Cartesian coordinates by lumped-parameter method, which is more accurate and may match with the physical model better than the purely torsional model. According to the design parameters of the 3-stage planetary gears of main reducer of shield tunnelling machine, the natural frequencies and vibration modes are investigated by using this transverse-torsional model.

Study on Dynamic Characteristics of Wind Turbine Planetary Gear System Coupled with Bearing at Varying Wind Speed

The sparse least squares support vector machines (SL-SVM) is used to simulate wind speed of real wind field, and time-varying wind load caused by stochastic wind speed is then obtained. A coupling gear-bearing dynamical model of planetary gear transmission system of wind turbine is built using lumped-parameter method, in which the varying wind load, time-vary mesh stiffness of gear pair and time-vary stiffness of rolling element bearing are taken into account. Numerical method is used to simulate the dynamic performance of planetary gear transmission of multibrid technology wind turbine (MTWT) with 1.5MW rated power, the vibration displacement responses of gears and dynamic meshing forces of gear pairs as well as nonlinear bearing forces in the transmission system are obtained, and the influence rules of external varying wind load on the vibration characteristics of transmission system of wind turbine are studied. The research results lay a foundation for dynamic performance optimization and reliability design of gear transmission system of wind turbine.

Modeling and Controlling of Anti-Slip Regulation Based on Limited-Slip Differential

The dynamic models of whole rear-wheel drive vehicle, limited-slip differential, hydraulic control system and electronic throttle were established. Simulations of acceleration course on split-µ road, checkerboard-µ road, low-µ road and step-µ road were carried out combining electronic throttle PI controller and limited-slip differential fuzzy controller. The results show that the Anti-slip Regulation quickly works according to the road adhesion coefficient, effectively inhibits the slip of driving wheels on low adhesion coefficient road, the acceleration performance driving on bad roads was improved obviously, and show a good adaptability.