| 摘要 |
PURPOSE:To approximate to an ideal curve for suitably maintaining the tensile force of a power transmission belt by providing a limit valve for limiting the rise in speed ratio pressure which is fed from a speed ratio detecting valve into a second pressure regulating valve to a defined value. CONSTITUTION:An oil pressure is fed from a first pressure regulating valve 100 into one of primary side and secondary side hydraulic actuators 70, 72 via a first oil passage 80 and a flow control valve 264 by means of a speed change directional selector valve 262, while working fluid in the other is discharged out into a second oil passage 82 and held at a second line pressure Pl2 by means of a second pressure regulating valve 102. The second pressure regulating valve 102 is controlled by a speed ratio oil pressure Pe from a speed ratio detecting valve 182, and the increase in the speed ratio oil pressure Pe above an upper limit value is prevented by a limit valve 210. Thereby, the second line oil pressure can be approximated to an ideal curve for suitably maintaining the tensile force of a power transmission belt. |
