公开(公告)号：CA2041593A1

公开(公告)日：1991-12-26

申请号：CA2041593

申请日：1991-05-01

Applicant: BORG WARNER AUTOMOTIVE ELECTRO

Inventor： STUDTMANN GEORGE H ,  FORBES TERRY L ,  WARD JAMES R

IPC: F16K31/06 ,  H02K41/00

Abstract: An improved electrically actuated solenoid is used to modulate the function of a hydraulic flow control valve. The solenoid operates a control valve to generate a predetermined output pressure as a function of the solenoid input current. An input pressure, provided to the control valve, can thus be modulated to provide a desired maximum controlled output pressure regardless of the input pressure by bleeding excessive pressure to a low pressure return circuit. A lower controlled output pressure is obtained by providing the solenoid with an input current creating a magnetic flux circuit within the solenoid. The magnetic flux circuit displaces an enhanced armature and pole piece configuration which provide a selectable output force dependent on the solenoid input current, regardless of the displacement of the armature relative to the pole piece. By increasing the air gap surface area and increasing the air gap permeability, increases in the output force obtainable from a solenoid of relatively small physical dimensions and relatively low cost is possible. The resulting improved output force versus current characteristics make the use of the solenoid of the present invention possible in a hydraulic control system to increase the portion of pressure bled to the low pressure hydraulic return circuit and thus reduce the controlled output pressure.