| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve power transmission efficiency while preventing slip of an endless belt of a belt type continuously variable transmission. <P>SOLUTION: Required axial thrust of either one of both pulleys is determined to prevent the slip of the endless belt. The required axial thrust is corrected by a correction coefficient based on deviation between estimated torque ratio and target torque ratio. A side pressure of either one of the pulleys is corrected based on the corrected required axial force. Therefore, the control accuracy of the pulley side pressure is not only improved because an error of an estimated value of the required axial thrust is absorbed by the feedback of the torque ratio during the steady state operation of the belt type continuously variable transmission. Further. the slip of the endless belt can also be prevented by making the required axial force respond instantaneously by the feedforward control when the pulley side pressure needs to be responded instantaneously like at a change of the transmission torque of the belt type continuously variable transmission. Thereby, control accuracy and control responsiveness are both achieved. <P>COPYRIGHT: (C)2013,JPO&INPIT |
