Patent ID: 8662272

Claim:
A pressure medium supply device of a hydraulically actuated shifting element (K 1 , K 2 ), the pressure medium supply device comprising: at least one pressure medium supply duct ( 1 , 2 ) selective connectable to one of a first line ( 3 ), for pre-filling the shifting element, and to a further line ( 8 ), a pressure-retaining valve ( 9 , 9 ′) being integrated in the pressure medium supply duct ( 1 , 2 ), between the shifting element and a shifting element valve ( 6 , 7 ), such that the pressure-retaining valve ( 9 , 9 ′) is closable in a draining direction of the pressure medium supply duct ( 1 , 2 ); and the pressure-retaining valve ( 9 , 9 ′), when in an opened position, facilitates draining of the shifting element and venting of the pressure medium supply device; wherein the pressure-retaining valve ( 9 , 9 ′) comprises a housing ( 12 ) with an inlet ( 13 ) and an outlet ( 14 ) which faces toward the shifting element (K 1 , K 2 ), a valve seat ( 15 ) is located within the housing ( 12 ) adjacent an outlet side of the pressure-retaining valve, a valve body ( 16 ) engages with the valve seat ( 15 ) is retained within the housing ( 12 ) by a closing cover ( 18 ) which has at least one opening ( 17 ); when a pressure on the outlet side of the pressure-retaining valve ( 9 , 9 ′), is greater than a pressure on an inlet side of the pressure-retaining valve ( 9 , 9 ′), the valve body ( 16 ) is forced against the valve seat ( 15 ) so as to close the pressure-retaining valve ( 9 , 9 ′); and the pressure-retaining valve ( 9 , 9 ′) further comprises a spring element ( 20 ) arranged, with pre-stress, between the valve seat ( 15 ) and either a cover element or a cover-plate ( 19 ) located on the inlet side of the pressure-retaining valve ( 9 , 9 ′), the spring element ( 20 ) is designed and pre-stressed such that the spring element ( 20 ) is only compressed when the pressure on the outlet side of the pressure-retaining valve ( 9 , 9 ′) exceeds the pressure on the inlet side of the pressure-retaining valve ( 9 , 9 ′) by a specific amount, to facilitate drainage of the shifting element (K 1 , K 2 ), which occurs by displacement of the valve seat ( 15 ) in a direction toward the inlet side of the pressure-retaining valve ( 9 , 9 ′) such that pressure medium flows past the valve seat ( 15 ) and out of the housing ( 12 ).