公开(公告)号：US10371216B2

公开(公告)日：2019-08-06

申请号：US15563130

申请日：2016-04-01

Applicant: Punch Powertrain N.V.

Inventor： Peter Mark Smid ,  Stefan Hubertus Godelieve Van Raemdonck

IPC: B60T13/12 ,  F15B11/16 ,  F16D48/02 ,  F16D25/12 ,  F16H61/00 ,  F16H61/02 ,  B60T15/02 ,  F16D67/04 ,  F15B13/02 ,  F15B13/06

Abstract: A hydraulic system for a multiple friction transmission, comprising: a first pressure relief valve 5 regulable by means of a first pilot pressure; a normally-open drain valve 8, which is a directional valve switchable between an open state and a closed state by means of a second pilot pressure; at least one first pressure regulator 11 for operating the drain valve by means of a first pilot pressure and a second pilot pressure, respectively; wherein in the event of detrimental hydraulic pressure build up, the second pilot pressure is dropped to open the drain valve, so as to relieve pressure through the drain line.