| 摘要 |
<p>A hydraulic control device controls hydraulic fluid for shifting an automatic transmission (11) by a pressure control valve (2), and supplies operating hydraulic fluid diverted from the pressure control valve (2) via a torque converter pressure passage (31) to a lock up clutch (12D) of the torque converter. A lubrication passage (37) which lubricates the automatic transmission (11) is connected via an orifice (8) to a torque converter pressure passage (31), and the pressure in this torque converter pressure passage (31) is limited by a regulator valve (3, 103) to a predetermined upper limit value. Further, there is included a bypass valve (3, 4, 103) which directly supplies hydraulic fluid from the torque converter pressure passage (31) via the orifice (8) to the lubrication conduit (37) when the pressure in the torque converter pressure passage (31) rises above a predetermined pressure. On the one hand, at times of low speed vehicle operation, the engagement pressure for the lock up clutch is ensured by the orifice (8), while also at times of high load the amount of lubrication hydraulic fluid is increased by the bypass valve (3, 4, 103). <IMAGE></p> |
