Patent ID: 7393299
Filing Date: 2008-07-01
Classification: F16H

Abstract:
1. A hydraulic control apparatus for an automatic transmission which includes a hydraulic power transmission device with a lock-up clutch, and in which a plurality of hydraulic engagement devices are selectively engaged to achieve any one of a plurality of shift speeds which have different speed ratios, the hydraulic control apparatus comprising: a first solenoid valve that controls an engagement pressure of a first engagement device that is engaged at a first predetermined shift speed, and that is disengaged at a second predetermined shift speed; a second solenoid valve that controls an engagement pressure of a second engagement device that is disengaged at the first predetermined shift speed, and that is engaged at the second predetermined shift speed; and at least one oil-passage selection device which selects between a first oil passage used to control an engagement pressure of the first engagement device and a second oil passage used to control a torque capacity of the lock-up clutch, and supplies a first control hydraulic pressure output from the first solenoid valve to the selected oil passage, and which selects between a third oil passage used to control an engagement pressure of the second engagement device and the second oil passage, and supplies a second control hydraulic pressure output from the second solenoid valve to the selected oil passage.