| 摘要 |
A hydraulic control apparatus for a continuously variable transmission which can produce stable drive pulley pressure and driven pulley pressure and also control the speed change time. The line pressure regulated by the regulator valve 22 is supplied to the control valve 24DR of the drive pulley 5 and to the control valve 24DN of the driven pulley 7. These control valves regulate the line pressure according to the PB pressure and the PC pressure output from the solenoid valves SOL-B, SOL-C, respectively, and produce the drive pulley pressure PDR and the driven pulley pressure PDN. When the PB pressure and the PC pressure are both zero, and PDR=PDN, the control apparatus maintains the same gear ratio. When the PB pressure is increased from zero while keeping the PC pressure at zero, i.e. PDR>PDN, the gear ratio changes toward the high-speed overdrive. When the PC pressure is increased from zero while holding the PB pressure at zero, i.e. PDR<PDN, the gear ratio changes toward the low-speed gear.
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