Hydraulic valve
AssigneeMoog Controls, Inc.
InventorMarkus C. Kihlberg
Life of this patent
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Abstract
A high speed high-performance valve member has a spool that is movable within a cylindrical cavity of a valve body or sleeve. The spool and sleeve are both formed of hardened stainless steel, but the bearing surfaces and lands of the spool are provided with a deposition layer of titanium nitride to give the bearing surface a hard smooth finish. The differential hardness between the spool and sleeve prevents galling. Damage due to cavitation is avoided, and the valve has a failure rate reduced by a factor of about twenty.
Claims7
A high speed hydraulic valve comprising a sleeve member and a spool member slidably mounted within the sleeve member;
- the sleeve member including a cylindrical cavity having a cylindrical surface and a plurality of ports permitting flow of fluid into and out of said cavity, said sleeve member being formed of a steel that has a surface hardness of about 55 to 60 Rc;
- said spool member including at least one cylindrical land having a cylindrical surface facing said cavity cylindrical surface and cooperating with said sleeve member ports such that the relative position of said sleeve member and said spool member define selective flow paths for said fluid, and at least one cylindrical bearing surface engaging a portion of the cylindrical cavity surface of said sleeve member, said spool having applied onto its at least one land and its at least one bearing surface a coating of titanium nitride to a thickness of about 50 to 200 microinches, such that the land cylindrical surface and the bearing cylindrical surface have a surface hardness of at least 10 Rc greater than the engaging surfaces of said sleeve member.
Dependencies are inferred from the claim text.