Patent ID: 8272486
Filing Date: 2012-09-25
Classification: F16H

Abstract:
1. A hydraulic control device for controlling hydraulic pressure of a torque converter with a lock-up clutch, the lock-up clutch being constructed from a hydraulic piston and a clutch member, the hydraulic piston being installed in an inner space of the torque converter so that an oil chamber is formed between the hydraulic piston and a cover of the torque converter, the clutch member causing the cover and a turbine runner of the torque converter to engage and be released due to movement of the hydraulic piston by supply and discharge of hydraulic oil to and from the oil chamber, the hydraulic control device comprising: a first shift valve for carrying out engagement control of the lock-up clutch by switching supply and discharge of the hydraulic oil to and from the oil chamber; a first oil discharge passage and a second oil discharge passage for deriving the hydraulic oil discharged from the oil chamber via the first shift valve; a second shift valve for switching the first oil discharge passage and the second oil discharge passage; first and second solenoid valves for respectively supplying controlled hydraulic pressure for controlling switching of the first and second shift valves to the first and second shift valves; and a control section for determining a driving state of a vehicle and controlling the first and second solenoid valves on the basis of the determined driving state, wherein an oil passage length of the second oil discharge passage is shorter than that of the first oil discharge passage and a discharge end of the second oil discharge passage is opened at a lower position than that of the first oil discharge passage, wherein the control section derives the hydraulic oil, discharged from the oil chamber via the first shift valve, to the first oil discharge passage by means of the second shift valve when it is determined that the driving state of the vehicle is one during normal driving, and wherein the control section derives the hydraulic oil to the second oil discharge passage by means of the second shift valve when it is determined that the driving state of the vehicle is one required for rapid lock-up off.