A vibration actuator includes: a fixing body having N-fold (N is a natural number) of 2 of core pole parts and a coil wound around each of the core pole parts; a movable body having a magnet part disposed being separated from each of the core pole parts in an axial direction of each of the core pole parts, for each of the core pole parts; and an elastic support part that movably supports the movable body, in which the magnet part has a magnetic pole disposed on each of the core pole part sides and facing each of the core pole parts, and in which the movable body vibrates in a direction orthogonal to both directions including a direction in which the N-fold of 2 of the core pole parts are aligned and the axial direction of the coil by the energization of the coil.

Provided according to the present invention is a solenoid with a built-in permanent magnet, with which it is possible to suppress an increase in the amount of magnetic flux that passes through the chuck part, even when the magnetic flux generated by a coil is greater than the magnetic flux of the magnet, and to reliably reduce attraction force. In this solenoid, a permanent magnet and a coil are both built into a cylindrical case having an opening part; the permanent magnet and the coil are both separated and arranged inside the case; a ring member is arranged adjacent to the permanent magnet; a movable iron core is inserted inside the coil; and between the movable iron core and the coil, a metal coil cover is provided so as to cover the coil. The distance d between the case inner wall and the ring member can also be in the range of 0.1-0.3 mm.

Provided according to the present invention is a solenoid with a built-in permanent magnet, with which it is possible to suppress an increase in the amount of magnetic flux that passes through the chuck part, even when the magnetic flux generated by a coil is greater than the magnetic flux of the magnet, and to reliably reduce attraction force. In this solenoid, a permanent magnet and a coil are both built into a cylindrical case having an opening part; the permanent magnet and the coil are both separated and arranged inside the case; a ring member is arranged adjacent to the permanent magnet; a movable iron core is inserted inside the coil; and between the movable iron core and the coil, a metal coil cover is provided so as to cover the coil. The distance d between the case inner wall and the ring member can also be in the range of 0.1-0.3 mm.

A torque motor for use in a servovalve wherein only two holes must be provided through each of the pole pieces in order to assemble the torque motor together. The torque motor comprises first and second opposing pole pieces, first and second permanent magnets positioned between the first and second pole pieces; an armature comprising a magnetic plate and a flapper, the magnetic plate being positioned between the first and second permanent magnets, the flapper being connected at one end to the magnetic plate; and further comprising: first and second fastening means each extending through the first pole piece, the armature and the second pole piece to thereby fasten the torque motor together.

A torque motor for use in a servovalve wherein only two holes must be provided through each of the pole pieces in order to assemble the torque motor together. The torque motor comprises first and second opposing pole pieces, first and second permanent magnets positioned between the first and second pole pieces; an armature comprising a magnetic plate and a flapper, the magnetic plate being positioned between the first and second permanent magnets, the flapper being connected at one end to the magnetic plate; and further comprising: first and second fastening means each extending through the first pole piece, the armature and the second pole piece to thereby fasten the torque motor together.

A valve includes an electrodynamic actuator which has a magnet arrangement for generating a magnetic field and a control element movable relative to the magnet arrangement. The control element includes an energizable coil which is arranged in the magnetic field and is firmly coupled to a coil carrier. The control element is movable between at least two defined positions. There are provided permanent-magnetically interacting holding force which retain the control element in at least one of the defined positions, even when the coil is currentless.

A valve includes an electrodynamic actuator which has a magnet arrangement for generating a magnetic field and a control element movable relative to the magnet arrangement. The control element includes an energizable coil which is arranged in the magnetic field and is firmly coupled to a coil carrier. The control element is movable between at least two defined positions. There are provided permanent-magnetically interacting holding force which retain the control element in at least one of the defined positions, even when the coil is currentless.

Disclosed is a magnetic force control device improved to be installed even in a narrow space having a small height. The magnetic force control device includes a first pole piece having a first interaction surface, a second pole piece having a second interaction surface, a third pole piece connected to the second pole piece, a coil wound around at least one of the second pole piece and the third pole piece, a stationary magnet fixed between the first pole piece and the second pole piece and a rotary magnet disposed between the first pole piece and the third pole piece and configured to be rotatable by controlling a current flowing through the coil.

Disclosed is a magnetic force control device improved to be installed even in a narrow space having a small height. The magnetic force control device includes a first pole piece having a first interaction surface, a second pole piece having a second interaction surface, a third pole piece connected to the second pole piece, a coil wound around at least one of the second pole piece and the third pole piece, a stationary magnet fixed between the first pole piece and the second pole piece and a rotary magnet disposed between the first pole piece and the third pole piece and configured to be rotatable by controlling a current flowing through the coil.

A solenoid is provided. The solenoid includes a housing, a pole piece, an end plate formed with or coupled to the housing, a wire coil arranged within the housing, a permanent magnet arranged between the pole piece and the end plate, an armature configured to selectively move between a first position and a second position in response to a current applied to the wire coil, and a spring configured to bias the armature. When the wire coil is de-energized, the armature is maintained in at least one of the first position and the second position. The first position is configured to be maintained by the spring and the second position is configured to be maintained by magnetic attraction between the armature and the permanent magnet through engagement between the armature and the pole piece.