Fluid pressure control system for automatic transmission

摘要

Herein disclosed is a fluid pressure control system which is to be used in an automatic transmission for automobiles. If a reverse range is selected by selector means such as a manual valve, a fluid pressure is fed via an accumulator to friction engaging means for setting the reverse range, and a signal pressure is fed to back pressure regulating means which is constructed of a spool valve. This back pressure regulating means responds to the signal pressure to reduce a load against the fluid pressure to be fed to the friction engaging means. Thus, the fluid pressure to be fed to the friction engaging means via the accumulator drops when the signal pressure is fed. In the reverse range, specifically, the fluid pressure to be fed to the friction engaging means transmits at a lower level to elongate the time period for the engagement so that the gear shift shock for the reverse range is accordingly reduced.