Development of Shaft Drive CVT for Automobiles Applying Crossed Axle Traction Drive

研制了轴驱动无级变速器(CVT)的新型机构。具有圆锥盘的输入轴和输出轴是平行的，并且两端具有圆锥滚子的空转轴垂直于输入/输出轴。该空转轴将扭矩从输入轴传递到输出轴，其直线运动通过改变输入/输出盘和空转辊之间的接触点来产生速度变化。在本研究项目期间，取得了以下成果。1)开发了圆盘的曲面形状，以减少对牵引接触性能有不利影响的旋转量。样机验证了该方法的效果。2)提出了一种独特的变速机构，并通过实验对其速度控制性能进行了评价。在S无级变速器样机中，只有一个电机用于驱动圆盘。该机构使用滚珠丝杠和齿轮系，开发时不使用任何液压系统。3)设计了支承圆锥滚子机构。它安装在托辊的对面，并与输入输出盘、备份盘以及托辊接触。它减少了输入/输出轴的轴承损耗，因为它在相反的一侧支持空转辊的轴向力。该机构增大了传递扭矩的大小。通过实验验证了支承辊的有效性，在高转化率下获得了98.4%的效率。

The novel mechanism CVT (Shaft Drive CVT) was developed by the authors. The input and output shafts with conical disks are parallel and an idler shaft having conical rollers at both ends is placed perpendicular to the input/output shafts. This idler shaft transmits torque from the input shaft to the output shaft and its linear motion produces the speed variation by changing the contact point between the input/output disk and the idler roller. During this research project term, following results are obtained. 1)The curved shape of disk to decrease an amount of spin that has adverse effect on traction contact performance was developed. The effect of it was confirmed by the prototype. 2)A unique ratio changing mechanism was developed and the speed control performance was evaluated by the experiments. In the prototype S-CVT, only one motor is used to actuate disks. The mechanism using a ball screw and a gear train is developed without using any hydraulic systems. 3)The backup conical roller mechanism was devised. It is mounted to the opposite side of the idler roller, and contact with the input/output disk and the backup disk as well as the idler roller. It reduces the bearing loss of the input/output shaft because it supports the axial force of idler roller at the opposite side. The amount of transmitted torque is enlarged by this mechanism. The effectiveness of the backup rollers was confirmed by the experiments, and the efficiency of 98.4% was obtained at high ratio.