US 9,810,342 B2
Solenoid spool valve
Richard Terrence Tamba, Castle Hill (AU)
Assigned to NT Consulting International Pty Limited, Castle Hill (AU)
Appl. No. 13/579,840
Filed by Richard Terrence Tamba, Castle Hill (AU)
PCT Filed Feb. 18, 2011, PCT No. PCT/AU2011/000174
§ 371(c)(1), (2), (4) Date Sep. 14, 2012,
PCT Pub. No. WO2011/100800, PCT Pub. Date Aug. 25, 2011.
Claims priority of application No. 2010900682 (AU), filed on Feb. 18, 2010.
Prior Publication US 2012/0326066 A1, Dec. 27, 2012
Int. Cl. F16K 11/07 (2006.01); F16K 31/06 (2006.01)
CPC F16K 31/0613 (2013.01) [Y10T 137/8671 (2015.04); Y10T 137/86622 (2015.04)] 15 Claims
OG exemplary drawing
 
1. A solenoid spool valve including:
a spool valve having a sleeve provided with a supply pressure port, a control pressure port, an exhaust port and a spool supported in the sleeve for axial displacement within the sleeve; and
an electromagnetic actuator for providing an axial drive force to said spool in a first axial direction;
wherein the spool has a first piston with a first land for opening/closing the supply pressure port to/from fluid communication with the control pressure port and a second piston with a second land for opening/closing the exhaust port to/from fluid communication with the control pressure port,
the first piston having a larger piston face surface area in fluid communication with the control pressure port than does the second piston to reduce leakage from the control pressure port to the exhaust port; and
a feedback to equalize pressure on equal and opposite face surface areas of the first piston,
wherein the feedback includes at least one of: a feedback orifice through a sidewall or end wall of the sleeve or end portion that connects to a fluid supply; and a feedback orifice formed as a duct extending through the first piston to communicate with the control pressure port, and
wherein the spool is arranged such that, for every stationary position of the spool valve, a combined force on the spool from fluid against piston faces of the spool is independent of a transverse extent of the first piston.