公开(公告)号：US4941371A

公开(公告)日：1990-07-17

申请号：US259962

申请日：1988-10-19

申请人： Hideo Koyama ,  Koji Sasajima ,  Kazuya Maki ,  Kouji Yamaguchi ,  Yoshikazu Ishikawa

发明人： Hideo Koyama ,  Koji Sasajima ,  Kazuya Maki ,  Kouji Yamaguchi ,  Yoshikazu Ishikawa

IPC分类号： B60W10/06 ,  B60W10/10 ,  B60W30/18 ,  F16H61/22 ,  F16H61/40 ,  F16H61/4052 ,  F16H61/42 ,  F16H61/425 ,  F16H61/46 ,  F16H61/465

CPC分类号： B60W10/06 ,  B60W10/04 ,  B60W10/103 ,  B60W10/11 ,  B60W30/18 ,  F16H61/4052 ,  F16H61/425 ,  F16H61/46 ,  F16H61/465 ,  F16H2059/363 ,  Y10T477/631 ,  Y10T477/636

摘要： A hydraulic continuously variable speed transmission with a direct clutch valve comprises a hydraulic pump, a hydraulic motor, a hydraulic closed circuit for hydraulically connecting the both, a direct clutch valve placed in the closed circuit, a speed reduction ratio control actuator, and a direct clutch valve controlling device for controlling operations of said direct clutch valve to block the closed circuit when the speed reduction ratio becomes substantially "1". The direct clutch valve controlling device maintains a direct connecting state when an actual engine speed is higher than a direct clutch disconnecting reference engine speed at the speed reduction ratio of approximately "1". Then, the direct clutch valve control device releases the blocking of the closed circuit by the direct valve when a drop of the actual engine speed from the direct clutch disconnecting reference engine speed exceeds a predetermined amount corresponding to the vehicle speed.