Patent ID: 6474456
Filing Date: 2002-11-05
Classification: F16H,Y10T

Abstract:
A hydraulic control apparatus for automatic transmissions provided with a hydraulic transmission unit in which a hydraulic lockup chamber of a lockup clutch is independent of a hydraulic transmission chamber, comprising:a valve body formed by laminating at least two members on each other and having: a pressure regulating valve adapted to regulate a hydraulic pressure supplied to the lockup clutch; a control unit adapted to supply a signal pressure to the pressure regulating valve; a source pressure oil passage adapted to supply a basic pressure for hydraulic pressure regulation; and a drain oil passage communicating with a drain port; and a separator plate inserted between the two members of the valve body; the pressure regulating valve having: a first port to which the signal pressure is applied from the control unit; a third port in communication with the hydraulic lockup chamber; a second port provided on one side of the third port; and a fourth port provided on the other side of the third port; an opening of an oil passage in communication with the second port and provided in one member of the valve body being formed so as to overlap both an opening of the source pressure oil passage and that of the drain oil passage which are provided in the other member of the valve body, an opening of an oil passage in communication with a fourth port and provided in said one member of the valve body being formed so as to overlap both an opening of the source pressure oil passage and that of the drain oil passage which are provided in said other member of the valve body; and wherein the separator plate is provided with communication ports for communicating the opening of the oil passage in communication with the second port and that of the source pressure oil passage with each other, and the opening of the oil passage in communication with the fourth port and that of the drain oil passage with each other.