Patent ID: 6056094
Filing Date: 2000-05-02
Classification: F16H

Abstract:
A hydraulic control device for use with an automatic transmission which is connected to a torque converter comprising a lock up clutch, said device comprising:a pressure control valve which controls hydraulic pressure supplied to said automatic transmission;a torque converter pressure passage which supplies hydraulic fluid for operating said lock up clutch from said pressure control valve to said lock up clutch; a lock up control valve which is provided in said torque converter pressure passage and controls engagement and disengagement of said lock up clutch;a lubrication passage which supplies hydraulic fluid for lubrication to said automatic transmission;an orifice which is provided between said pressure control valve and said lock up control valve and joins said torque converter pressure passage to said lubrication passage;a regulator valve which limits the pressure in said torque converter pressure passage to within a predetermined upper limit value; anda bypass valve detouring said orifice for supplying hydraulic fluid from said torque converter pressure passage to said lubrication passage when the pressure in said torque converter pressure passage rises above a predetermined value.