EP 0078861 B1 19850320 - PRESSURE-CONTROL SYSTEM
Title (en)
PRESSURE-CONTROL SYSTEM
Publication
Application
Priority
EP 81109581 A 19811110
Abstract (en)
[origin: EP0078861A1] 1. Pressure control device, which has a hydraulically acting servo-piston (23), the displacement of which leads to a change in the hydraulic flow to the consumer (22), with the following construction : (a) a pressure control valve (1) has a valve spring (14) in a spring chamber (13) and a spool (7) with two pressurised sides (7a, 7b), of which one side (7a) is connected to the pump line (21) and the other side (7b) to the spring chamber (13), and both sides (7a, 7b) are connected together hydraulically by a restrictor (25) ; (b) when there is an imbalance of forces at the spool (7), a pressure line (9) or a tank line (11) connects with a control line (10), which leads to and away from the servo-piston (23) ; characterized in that (c) the spring member (13) is connected to a supplementary volume (15), which produces a displacement flow by displacing fluid in an adequately large quantity through the restrictor (25) when there are increases in pump pressure, the rate of this displacement flow depending on the increase rate of the pump pressure, and which produces a pressure drop (P1 - P2 ) between the two sides (7a, 7b) of the spool, by which means a force imbalance well below the nominal pressure (Pn ) develops at the spool (7), which leads to a premature (t1 ) pressure limiting action.
IPC 1-7
IPC 8 full level
F04B 49/08 (2006.01)
CPC (source: EP)
F04B 49/08 (2013.01)
Designated contracting state (EPC)
DE FR GB IT SE
DOCDB simple family (publication)
EP 0078861 A1 19830518; EP 0078861 B1 19850320; DE 3169441 D1 19850425
DOCDB simple family (application)
EP 81109581 A 19811110; DE 3169441 T 19811110