A clutch in an automatic transmission

摘要

A control and regulating valve 3 which controls a clutch in an automatic transmission comprises a housing 4 and an axially moveable spool 5 that is moved by application of a magnetic force Fmag exerted on one end of the spool 5. At an opposite end of the spool 5 there is a rear chamber 7 and an accumulator consisting of a fixed plate with a central hydraulic opening 9, a spring 10 and a disc 11. The rear chamber 7 has an opening that is directly coupled to the clutch so that line pressure may be applied when the spool 5 has been moved to a certain position under the influence of the magnetic force Fmag which is due to a command current. The accumulator acts as a low frequency filter and the hydraulic opening 9 has to be calibrated to optimize dynamic behaviour in order to reduce or even eliminate oscillation amplitudes.