Applicatin of a half-toroidal continuously variable transmission to an electric-vehicle drive-train and visualization of air-bubble behavior in the traction contact

本研究是一个挑战，即通过应用最小的电力来实现机械上可变的电力传输，获得电动车辆的最大加速。一个半速连续可变功率传输， CVT，具有快速速率变化和安静的特点，以及在启动时对刹车-能量恢复和高加速的快速响应。在这项研究中，一种新型的无级变速器是设计、制造和应用于装有2.2千瓦马达的电动汽车。（1）无级变速器的性能测试结果的速度传输效率为98%，扭矩传输效率为78%，转速为1500转速，扭矩范围为10 - 40牛顿·米，速度比范围为0.4 - 2.5。扭矩的主要损失是由一对强力球轴承来支持发射扭矩，而哪一个是由理论分析预测的。（2） Next the vehicle performance tests clarify that the maximum electric power-duration of 200 A，36 V at starting is reduced by 20%，the maximum speed is increased to 40 km/h from 20 km/h by the equipment of the CVT.On the basic research of traction fluid， it is succeeded to visualize small bubble behavior running into thin film gap by using the high speed video-camera。小泡沫的主要流掩盖了缺口，但10%的泡沫通过了缺口的改变。这将是在高赫兹压力下发生闪光温度上升的原因，因为它有时会在高温度下经历，以至于错过了泡沫消除流量的能力。

This research is a challenge of getting maximum acceleration of an electric vehicle with minimum electric power by applying a mechanically variable power-transmission. A half-toroidal continuously variable power transmission, CVT,has features of quick speed-ratio changing and quietness, which suits quick response for braking-energy recovery and high acceleration at starting. In this research, a new type of CVT is designed, manufactured and applied to an electric vehicle with 2.2 kw motor. (1) The performance test-result of the CVT is speed-transmission efficiency of 98%, torque-transmission of 78% at rotational speed of 1500 rpm and torque range of 10 to 40 N・m in the speed-ratio range of 0.4 to 2.5. The main loss of torque is caused by a pair of thrust ball bearings for supporting the transmitting torque, which is predicted by the theoretical analysis. (2) Next the vehicle performance tests clarify that the maximum electric power-duration of 200A,36V at starting is reduced by 20% and the maximum speed is increased to 40km/h from 20km/h by the equipment of the CVT.On the basic research of traction fluid, it is succeeded to visualize small bubble behavior running into thin film gap by using the high speed video-camera. Primary stream of small bubbles is avoiding the gap but 10% of them go through the gap by deforming their shape. It will be a reason of the flash temperature rise at high Hertzian pressure contact for which it is sometimes experienced at high temperature due to lack of bubble erasing capability of traction fluid.