Electromagnetic actuator permanent magnet
First Claim
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1. An electromagnetic actuator, comprising:
- an armature made of a magnetic material;
a stator core made of a magnetic material and having a housing movably accommodating said armature in an axial direction, said stator core having an attracting portion located on an axial end;
a coil disposed on an outside of said stator core for generating a magnetic flux passing through said armature and said stator core; and
a permanent magnet disposed on said stator core for generating a magnetic flux passing through said housing in the same direction as said magnetic flux generated by said coil, wherein said housing has a thin wall located on a radial outside of said armature.
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Abstract
An electromagnetic actuator has a stator core, an armature and a coil. The stator core is formed as a seamless cylindrical tube having a thin wall as a magnetic restrictor. The thin wall has a thickness sufficient to maintain a mechanical strength of the stator core. A permanent magnet is located on an outside of the thin wall to generate a magnetic flux passing through the thin wall in the same direction as a magnetic flux generated by the coil. The thin wall is magnetically saturated with the magnetic flux generated by the permanent magnet. When the coil is energized, a magnetic flux generated by the coil gets around the saturated thin wall and passes through the armature.
57 Citations
37 Claims
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1. An electromagnetic actuator, comprising:
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an armature made of a magnetic material;
a stator core made of a magnetic material and having a housing movably accommodating said armature in an axial direction, said stator core having an attracting portion located on an axial end;
a coil disposed on an outside of said stator core for generating a magnetic flux passing through said armature and said stator core; and
a permanent magnet disposed on said stator core for generating a magnetic flux passing through said housing in the same direction as said magnetic flux generated by said coil, wherein said housing has a thin wall located on a radial outside of said armature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
a cylindrical valve housing having a plurality of ports forming a fluid passage;
a spool disposed in said valve housing and operated by said armature, said spool for changing a communicating condition between said ports; and
a resilient member pushing said spool against an attracting direction of said armature.
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15. An electromagnetic actuator according to claim 14, wherein said fluid is oil, and said ports includes an output port where a controlled pressure of oil is supplied.
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16. An electromagnetic actuator, comprising:
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an armature movably supported in an axial direction;
a stator core made of a magnetic material having a seamless housing accommodating said armature, said housing having a thin wall located on a radial outside of said armature;
a coil disposed on an outside of said stator core for generating a magnetic flux passing through said armature and said stator core; and
a permanent magnet disposed on a radial outside of said thin wall, said permanent magnet having poles on both axial ends to generate a magnetic flux passing through said thin wall in the same direction as said magnetic flux generated by said coil. - View Dependent Claims (17, 18)
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19. An electromagnetic actuator, comprising:
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an armature made of a magnetic material;
a stator core made of a magnetic material and having a housing movably accommodating said armature in an axial direction, said stator core having an attracting portion located on an axial end;
a coil disposed on an outside of said stator core for generating a magnetic flux passing through said armature and said stator core; and
a permanent magnet disposed on said stator core for generating a magnetic flux passing through said housing in the same direction as said magnetic flux generated by said coil, wherein said housing has a concave portion where said permanent magnet is fixed. - View Dependent Claims (20, 21, 22, 23, 24)
a cylindrical valve housing having a plurality of ports forming a fluid passage;
a spool disposed in said valve housing and operated by said armature, said spool for changing a communicating condition between said ports; and
a resilient member pushing said spool against an attracting direction of said armature.
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25. An electromagnetic actuator, comprising:
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an armature made of a magnetic material;
a stator core made of a magnetic material and having a housing movably accommodating said armature in an axial direction, said stator core having an attracting portion located on an axial end;
a coil disposed on an outside of said stator core for generating a magnetic flux passing through said armature and said stator core; and
a permanent magnet disposed on said stator core for generating a magnetic flux passing through said housing in the same direction as said magnetic flux generated by said coil, wherein said stator core has an axial end portion where said permanent magnet is located, and wherein said housing and said attracting portion are magnetically connected via a magnetic restricting portion disposed therebetween, the magnetic restricting portion being magnetically saturated by magnetic flux supplied by said permanent magnet. - View Dependent Claims (26, 27, 28, 29)
a cylindrical valve housing having a plurality of ports forming a fluid passage;
a spool disposed in said valve housing and operated by said armature, said spool for changing a communicating condition between said ports; and
a resilient member pushing said spool against an attracting direction of said armature.
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30. An electromagnetic actuator, comprising:
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an armature made of a magnetic material;
a stator core made of a magnetic material and having a housing movably accommodating said armature in an axial direction, said stator core having an attracting portion located on an axial end;
a coil disposed on an outside of said stator core for generating a magnetic flux passing through said armature and said stator core; and
a permanent magnet disposed on said stator core for generating a magnetic flux passing through said housing in the same direction as said magnetic flux generated by said coil, wherein said permanent magnet is located on a portion where a magnetic flux of said coil is scattered. - View Dependent Claims (31, 32)
a cylindrical valve housing having a plurality of ports forming a fluid passage;
a spool disposed in said valve housing and operated by said armature, said spool for changing a communicating condition between said ports; and
a resilient member pushing said spool against an attracting direction of said armature.
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33. An electromagnetic actuator, comprising:
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an armature made of a magnetic material;
a stator core made of a magnetic material and having a housing movably accommodating said armature in an axial direction, said stator core having an attracting portion located on an axial end;
a coil disposed on an outside of said stator core for generating a magnetic flux passing through said armature and said stator core; and
a permanent magnet disposed on said stator core for generating a magnetic flux passing through said housing in the same direction as said magnetic flux generated by said coil, wherein said housing has a tapered portion, said tapered portion decreasing in cross sectional area from said attracting portion to a portion located radial outside of said armature. - View Dependent Claims (34, 35)
a cylindrical valve housing having a plurality of ports forming a fluid passage;
a spool disposed in said valve housing and operated by said armature, said spool for changing a communicating condition between said ports; and
a resilient member pushing said spool against an attracting direction of said armature.
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36. An electromagnetic actuator, comprising:
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an armature made of a magnetic material;
a stator core made of a magnetic material and having a housing movably accommodating said armature in an axial direction, said stator core having an attracting portion located on an axial end;
a coil disposed on an outside of said stator core for generating a magnetic flux passing through said armature and said stator core; and
a permanent magnet disposed on said stator core for generating a magnetic flux passing through said housing in the same direction as said magnetic flux generated by said coil, wherein said armature is a column having an axial length L and a diameter D, said column having a ratio L/D which is not less than 1.0, and wherein said housing and said attracting portion are magnetically connected via a magnetic restricting portion disposed therebetween, the magnetic restricting portion being magnetically saturated by magnetic flux supplied by said permanent magnet. - View Dependent Claims (37)
a cylindrical valve housing having a plurality of ports forming a fluid passage;
a spool disposed in said valve housing and operated by said armature, said spool for changing a communicating condition between said ports; and
a resilient member pushing said spool against an attracting direction of said armature.
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Specification
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Current AssigneeDENSO Corporation
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Original AssigneeDENSO Corporation
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InventorsOishi, Kenichi, Aoki, Tetsuya, Tachibana, Seiji, Ando, Motoyoshi, Nakane, Hiroyuki
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Primary Examiner(s)Nguyen, Tran
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Assistant Examiner(s)Addison, Karen B
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Application NumberUS09/597,819Time in Patent Office918 DaysField of Search310/12, 310/14, 310/193, 137/625.5, 137/909, 137/625, 251/48, 335/297, 335/28, 335/278US Class Current310/214CPC Class CodesF02M 51/0614 characterised by arrangemen...F02M 51/0678 all portions having fuel pa...F16K 31/0613 with cylindrical slidesF16K 31/0624 Lift valvesF16K 31/0651 the fluid passing through t...F16K 31/0668 Sliding valvesF16K 31/082 using a electromagnet and a...H01F 7/081 Magnetic constructionsH01F 7/1607 Armatures entering the winding
