| 摘要 |
PROBLEM TO BE SOLVED: To dispense with a dedicated solenoid valve for actuating a rearward shift prohibiting valve so as to reduce the number of parts, and simplify hydraulic circuits in a hydraulic control device for a continuously variable transmission. SOLUTION: A shift ratio control solenoid valve controls a shift ratio control valve and a rearward shift prohibiting valve by control hydraulic pressure to change the shift ratio control valve to a shift-up region to feed working fluid to a primary side hydraulic chamber, a shift-down region to discharge the working fluid from the primary side hydraulic chamber, and a neutral position to hold the working fluid of the primary side hydraulic chamber between the shift-up region and the shift-down region. The rearward shift prohibiting valve is controlled to prohibit setting of rearward shift with the shift-up region, and permit setting of the rearward shift with the neutral position and the shift-down region. In a case where vehicle speed is more than prescribed, a control means changes the shift ratio control solenoid valve to the shift-up region for prohibiting setting of the rearward shift. COPYRIGHT: (C)2004,JPO |
