摘要 |
In a pressure regulation valve having a main spool and a sub-spool slidably housed in the main spool, the main spool is at a position where pilot pressure force balances with a sum of pressure force of a feedback chamber and spring biasing force, when the pilot pressure is below a given value, so that normal output pressure proportional to pilot pressure is supplied to a hydraulic servo for driving a clutch of an automatic transmission, and, when the pilot pressure exceeds the given value, the sub-spool moves to a position where the feedback chamber communicates with a drain so that the main spool moves to a position where maximum output pressure equal to supply pressure source is supplied.
|