| 摘要 |
PURPOSE:To correctly perform oil pressure control without causing wrong operation, by arranging oil pressure, fed to an oil hydraulic servomechanism for urging a multiple disc clutch and multiple disc brake, independently controllable with a respective shift control valve and solenoid valve. CONSTITUTION:An oil pressure control circuit for a stepless speed change gear is provided with a shift control mechanism 70 for controlling the timing of engagement for a multiple disc brake and multiple disc clutch in a planetary gear speed changer, and the mechanism 70 comprises a shift control valve 71 and solenoid valve 74. The shift control valve 71 comprises the first oil chamber 713, fed with pressure oil from an oil pressure source 50 through an orifice 72, the second and third oil chambers 701, 703, for feeding pressure oil to an oil hydraulic servomechanism that actuates the multiple disc brake and clutch through oil passages 14 and 13, and the fourth and fifth oil chambers 705, 717 for performing feedback of output oil pressure from these oil chambers 701, 703. The solenoid valve 74 is so provided as to discharge the oil pressure in the above described first oil chamber 713. |
