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US 7,459,813 B2Granted
Magnet rotor and electromagnetically-driving device using the same, and optical apparatus with light quantity-control device
AssigneeNisca Corporation
InventorsHiroaki Naganuma, Tokuro Kusunoki
Life of this patent
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Abstract
An electromagnetic device includes a magnet rotor having a rotary shaft and a stator having an excitation coil configured to apply a rotation force to the rotor. The magnet rotor includes a hollow cylindrical permanent magnet, a rotary shaft disposed in a hollow space portion of the permanent magnet, and a driving arm that rotates around the rotary shaft integrally with the permanent magnet. The magnet and driving arm are reliably secured, not easily separated during use, and includes a structure that facilitates machining and assemble.
Claims8
A magnet rotor comprising:
- a rotary shaft;
- a hollow cylindrical permanent magnet having a center, in which the rotary shaft is disposed, the permanent magnet having a first fitting part formed in an upper end face in a direction of the rotary shaft and composed of one of a protrusion and a concave groove;
- a driving arm rotating around the rotary shaft integrally with the permanent magnet, the driving arm having a second fitting part formed therein and composed of a protrusion or concave groove to mate with the first fitting part;
- and
- a pair of upper and lower rotor supporting members supporting a rotor assembly including the rotary shaft, permanent magnet, and driving arm;
- wherein a depth of fitting between the first and second fitting parts is set so that a length of a combination of the permanent magnet and driving arm is longer than a length of a distance between a pair of upper and lower supporting faces formed on the paired rotor supporting members when the rotor assembly is supported between the paired upper and lower supporting faces.
3 more elements
An electromagnetically-driving device, comprising:
- a hollow cylindrical permanent magnet having an internal circumferential face, an external circumferential face, and a first fitting part formed in an upper end face and comprising one of a protrusion and a concave groove;
- a rotary shaft forming a rotation center of the permanent magnet so that the permanent magnet is supported between a pair of upper and lower rotor supporting members through the rotary shaft;
- a driving arm rotating integrally with the permanent magnet, and including a second fitting part formed therein and comprising a protrusion or concave groove configured to mate with the first fitting part;
- an inside yoke disposed on a side of the internal circumferential face of the permanent magnet, the inside yoke including a core member fitted and disposed to a hollow-side internal circumferential face of the permanent magnet and having a bearing-fit bore, the core member including a third fitting part having a form substantially identical to a form of the first fitting part formed in the permanent magnet;
- an outside yoke disposed on a side of the external circumferential face of the permanent magnet, the outside yoke including a pair of magnetic pole-guide pieces made of a soft magnetic material and opposed to each other so that magnetic poles formed in the permanent magnet is located therebetween;
- and
- an excitation coil configured to generate a magnetic field in the inside and outside yokes;
- wherein depths of fitting of the first fitting part and the second and third fitting parts are set so that a length of a combination of the permanent magnet, driving arm and core member is longer than a supporting distance of the paired upper and lower rotor supporting members;
- and the permanent magnet and driving arm are rotatably supported between the paired rotor supporting members.
6 more elements
Dependencies are inferred from the claim text.