| 摘要 |
<p>A hydraulic control device for an automatic transmission for controlling a pressure control valve provided in a hydraulic circuit connected to a hydraulic pump to control a line pressure in the hydraulic circuit so that the pressure control valve is operated in its closing direction according to an increase in torque reaction force generated in a speed reducing mechanism provided between a starting clutch and the automatic transmission, thereby increasing the line pressure. The speed reducing mechanism is configured by a planetary gear mechanism. An operating arm is fixed to a sun gear shaft nonrotatably mounted on a sun gear of the planetary gear mechanism. The operating arm is located so as to abut against a spring retainer for retaining a reaction spring in the pressure control valve. Accordingly, when the torque reaction force acting on the sun gear is not greater than an initial set value for the reaction spring, the line pressure is maintained at a low pressure, whereas when the torque reaction force becomes greater than the initial set value, the line pressure is increased with an increase in the torque reaction force by operating the pressure control valve in its closing direction.</p> |
