Brushless electric machine and apparatus using the same
View Patent ↗A first member has a magnet assembly that includes at least one permanent magnet pair, and a second member includes an electromagnetic coil. A control circuit controls the supply of power to the electromagnetic coil as well as regeneration of power from the electromagnetic coil. The permanent magnet pair generates its strongest magnetic field along a magnetic field direction on homopolar contact planes where first magnetic poles contact one another, outward from the center of the permanent magnet pair along the magnetic field direction. The electromagnetic coil is positioned such that current will flow in a direction intersecting the magnetic field direction.
1. A brushless electric machine comprising:
a first member with a magnet assembly that includes at least one permanent magnet pair, each magnet of the magnet pair having a first magnetic pole and a second magnetic pole, the two magnets of each magnet pair being held such that the first magnetic poles contact one another;
a second member including a electromagnetic coil, the first and second members being changeable in position relative to one another; and
a control circuit that controls supply of to the electromagnetic coil or regeneration of power from the electromagnetic coil;
wherein the permanent magnet pair generates strongest magnetic field along a magnetic field direction lying in a homopolar contact plane at which the first magnetic poles contact one another, and outward from a center of the permanent magnet pair along the magnetic field direction;
the electromagnetic coil is positioned such that current will flow in a direction intersecting the magnetic field direction; and
the control circuit performs at least one of:
(i) drive control to operate the brushless electric machine in a prescribed driving direction, by supplying the electromagnetic coil with driving current in a prescribed first current direction without changing the direction of current supplied to the electromagnetic coil; and
(ii) regeneration control to regenerate DC power generated by the coil caused by relative movement of the first and second members along a prescribed direction.
2. The brushless electric machine according to claim 1 , wherein
the magnet assembly includes a electromagnetic yoke member contacting the second magnetic pole.
3. The brushless electric machine according to claim 2 , wherein
the magnet assembly includes two or more of the permanent magnet pairs, and the electromagnetic yoke member is disposed between adjacent permanent magnet pairs.
4. The brushless electric machine according to claim 1 , wherein
the first and second members are moveable relatively along a direction perpendicular to the homopolar contact plane.
5. The brushless electric machine according to claim 1 , wherein
the first and second members are moveable relatively along a prescribed direction parallel to the homopolar contact plane.
6. The brushless electric machine according to claim 1 , wherein
in the drive control, the control circuit is capable to operate the brushless electric machine in a reverse direction by supplying the electromagnetic coil with a driving current in a second current direction opposite to the first current direction.
7. The brushless electric machine according to claim 1 , wherein
the permanent magnet has a recessed portion or a salient portion disposed along a direction intersecting the driving direction.
8. The brushless electric machine according to claim 1 , wherein
the brushless electric machine is a rotary motor.
9. The brushless electric machine according to claim 1 , wherein
the brushless electric machine is a linear motor.
10. An apparatus comprising,
a brushless electric machine according to claim 1 ; and
a driven member driven by the brushless electric machine.
11. The apparatus according to claim 10 , wherein
the apparatus is an electronic device.
12. The apparatus according to claim 11 , wherein the electronic device is a projector.
13. The apparatus according to claim 10 , wherein
the apparatus is a fuel cell-powered device including a fuel cell for supplying power to the brushless motor.
14. The apparatus according to claim 10 , wherein
the apparatus is a robot.
15. The apparatus according to claim 10 , wherein
the apparatus is a moving body.