To provide a hydraulic control device of an automatic transmission, flowing a working fluid smoothly through a common drain passage for a plurality of hydraulic control valves.
In the hydraulic control device, a drain port 90 for a plurality of the hydraulic control valves 32 is connected by one common drain oil passage 93 (91, 92). A partitioning wall 95 is formed at a place where the drain oil passage 92 extending from the drain port 90 of a hydraulic control valve 32O arranged at the upper stream side out of the hydraulic control valve 32 is merged into the drain port 90 of a hydraulic control valve 32C arranged at the downstream side so that the working fluid does not flow into the drain port 90 of the hydraulic control valve 32C from the drain oil passage 92. Even when the discharge amount of working fluid flowing through the drain oil passage 92 increases, therefore, the working fluid is introduced into the drain oil passage 91 by the wall 95, so that the hydraulic control valve 32C is prevented from being improperly operated due to the working oil flowing from the drain port 90 into an output port 38.
NISHIO SATOSHI
TSUCHIDA KENICHI
SUZUKI AKITOMO
ISHIKAWA KAZUNORI
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