Patent ID: 6475113
Filing Date: 2002-11-05
Classification: F16H,Y10T

Abstract:
A hydraulic control system of an automatic transmission including a plurality of engaging elements, a plurality of hydraulic servos each receiving a hydraulic pressure so as to control the respective engaging elements, and a plurality of shifting means for outputting the hydraulic pressure supplied to the respective hydraulic servo to achieve a plurality of forward speeds by engaging and disengaging the corresponding engaging elements, said hydraulic control system comprising:a first hydraulic servo, included in the plurality of hydraulic servos, for an engaging element engaged upon attaining at least one high speed and disengaged upon attaining at least one low speed; and a supply switching means for switching a supply and discharge of the hydraulic pressure to the first hydraulic servo corresponding to a supplying state of a hydraulic pressure supplied to the first hydraulic servo, when all of the shifting means is in the event of a failure.