Solenoid spool valve
AssigneeNT Consulting International Pty Limited
InventorRichard Terrence Tamba
Life of this patent
Estimating the term…
Abstract
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 the spool in a first axial direction; wherein the spool has a first piston with a first land for opening/closing the supply pressure port and a second piston with a second land for opening/closing the exhaust port, wherein the first piston has a larger piston face surface area in fluid communication with the control pressure port than does the second piston.
Claims15
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.
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 pressure port;
- and
- a feedback orifice to equalize pressure on equal and opposite face surface areas of the first piston,
- 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.
Dependencies are inferred from the claim text.