| 摘要 |
A hydraulic control apparatus for use with a vehicle's automatic transmission, the apparatus including a fail-safe switch valve which has an escape-related output port connected to a drain port of a transmission-related solenoid valve corresponding to an escape-related frictional coupling device to establish an escape-related speed step, and additionally has an escape-related input port to which a hydraulic pressure is inputted, and a drain port from which a hydraulic fluid is drained, wherein the fail-safe switch valve is selectively switchable to a normal communication state thereof in which the escape-related output port and the drain port are communicated with each other and the escape-related input port is shut off, and to a fail-related communication state thereof in which the escape-related output port and the escape-related input port are communicated with each other, and the drain port is shut off, so that a hydraulic pressure is supplied from the escape-related output port of the fail-safe switch valve to the drain port of the transmission-related solenoid valve corresponding to the escape-related frictional coupling device.
|
