| 摘要 |
PURPOSE:To dispense with a solenoid valve exclusively used for locking up as well as to aim at low-unit cost of production, by letting a second solenoid valve for a second shift valve in a lockup control device function as a lockup controlling solenoid valve. CONSTITUTION:In case of a torque converter 42 carrying a lockup clutch 41 and an automatic transmission consisting of a shift mechanism 60 carrying various friction engaging elements and a hydraulic control unit 90, a lockup control device is constituted of each of first and second solenoid valves SOL1, SOL2, first and second shift valves 10, 20 and a lockup relay valve 30. When a car speed reaches such a range as suitable for locking up in a third speed, SOL1 is set to 'open', and the SOL2 to 'close,' then a spool 12 of the first shift valve 10 is moved up and down, while a spool 22 of the second shift valve 20 is moved down. And, line pressure is led into the lockup relay valve 30 via each of shift valves 20 and 10, making its spool 32 move downward, and hydraulic fluid is led into the cluth 41 and both are thus coupled.
|
