| 摘要 |
PURPOSE:To perform reliable engagement and disengagement of a lock-up clutch through improvement of oil pressure relation between a lock-up clutch oil chamber and a torque converter chamber, by installing an orifice and a bypass passage, bypassing the orifice, upstream from the torque converter chamber. CONSTITUTION:In an automatic transmission gear having a torque converter with a lock-up device, an orfice 140 is located in the port 130e of a lock-up control valve 130. In relation to a car speed cut valve 161, a spool 131 in the control valve 130 moves, the oil pressure in an oil passage 137, or the oil pressure in a torque converter chamber 106 is reduced to a low pressure, which passes the orifice 140, when the hydraulic oil in a lock-up clutch oil chamber LC is not drained, and set to a hydraulic pressure, which bypasses the orifice 140, when the hydraulic oil in the LC is drained. Thus, in their respective cases, a difference between the hydraulic pressures exerted on both sides of a lock-up clutch L becomes wide, resulting in performing reliable engagement and disengagement of the lock-up clutch L. |
