Direct-acting servo valve
AssigneeHitachi, Ltd.
InventorsKen Ichiryu, Haruo Watanabe, Takashi Yamaguchi
Life of this patent
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Abstract
A direct-acting servo valve wherein a spool is directly driven by a force motor including a coiled first bobbin located in a first magnetic circuit composed of a first yoke and a first magnet mounted on the yoke includes a second magnetic circuit composed of a second yoke and a second magnet located at one end of the spool, and a third magnetic circuit composed of third magnets and a magnetic member located at the other end of the spool. The second magnetic circuit serves as means for detecting the velocity of the spool, and the third magnetic circuit serves as means for detecting the displacement of the spool.
Claims7
In a direct-acting servo valve wherein a spool is directly driven by a force motor including a coiled first bobbin located in a first magnetic circuit composed of a first yoke and a first magnet mounted on the yoke, the improvement comprising:
- a second magnetic circuit composed of a second yoke and a second magnet located at one end of the spool and serving as a means for detecting the velocity of the spool;
- and
- a third magnetic circuit composed of third magnets and a magnetic member located at the other end of the spool and serving as a means for detecting the displacement of the spool.
A direct-acting servo valve comprising a valve body;
- a spool mounted in said valve body for axial movement;
- a force motor for directly driving said spool, said force motor including a coiled first bobbin located in a first magnetic circuit comprising a first yoke and a first magnet mounted on the first yoke;
- means for detecting the velocity of said spool, said velocity detecting means including a second magnetic circuit comprising a second yoke and a second magnet located at one end of the spool and a coiled second bobbin mounted for movement with said spool and inserted between said second yoke and said second magnet;
- and means for detecting the displacement of said spool, said displacement detecting means comprising third magnets and a magnetic member located at the other end of the spool, said third magnets being attached to said other end of the spool for movement with said spool and said third magnetic member being mounted on said servo valve adjacent said other end of the spool and located between said third magnets.
Dependencies are inferred from the claim text.