| The metal belt continuously variable transmission(CVT), which is very popular in the filed of auto industry, can achieve the best match of the engine power and real-time operating conditions through the automatic, continuous speed ratio changement. But the CVT itself friction transmission inherent power loss and the overflow throttle loss of hydraulic system have become the key factor in restricting the large-scale equipment in the car. Starting from the analysis of itself power loss, selecting the appropriate lubricate and cool way and reducing the overflowing loss and throttling loss of hydraulic system under every operating condition through optimizing design and control are the important way to realize the goal of improving its efficiency and the further implementation of energy-saving emission reduction. At the same time, energy saving and control the development of CVT can be generalized to other automatic transmission, which has important scientific significance.Based on The National Natural Science Fund Project "hydraulic system of CVT optimal flow distribution analysis and control(fund number: 51175156)".Aim at the analysis of CVT metal belt friction power loss and lubrication, cooling system, the main work is as follows:1. The principle of kinematics of metal belt transmission process, the stress of metal belt transmission process and torque capacity are analyzed, and considering the effects of slip and axial deflection on the transmission efficiency.2. Analysis of metal belt transmission based on dynamics, the power loss CVT metal belt transmission components in the transmission process is divided into four parts for research, and establishes a mathematical model of power loss of every part. In particular, considering the friction and lubrication in different working conditions are different, the metal belt and the belt wheel of the tangential friction power loss is divided into large, small load of two cases were analyzed, in order to ensure the accuracy of the model. Based on the model, calculation and typical operating conditions of the power loss, to analyze the power loss of different drive ratio, the power loss curve, results show that the power loss with the transmission ratio increases and decreases first and then increases, increasing the transmission ratio for CVT high transmission efficiency.3. Research and design of the stepless speed variator lubricating and cooling system, the metal belt assembly based on power loss data, confirming the target cooling flow requirements, detailed calculation of the main structure parameters of the system, and analyses the optimization.4. CVT integrated test platform based on experiment design, completed the lubricating and cooling system, and carry on the lubrication and cooling system of bench test, combined with vehicle test, results show that, during the whole working process of CVT, the oil temperature inside the CVT can maintain the overall work best within the oil, lubricating and cooling system the design can satisfy the use requirement. |
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