1. An electric fan comprising:
a frame having a central tube extending therefrom, the frame defining an air inlet and an air outlet at two different sides thereof;
a bearing received in the central tube;
a stator mounted around the central tube, the stator comprising a stator core having a central cylinder, a plurality of radial posts extending from the central cylinder, a stator coil wound around each of the radial posts, and a plurality of magnetic poles formed at free ends of the posts, each magnetic pole comprising a lower portion adjacent to the air outlet and an upper portion adjacent to the air inlet, the upper portions expanding radially along a direction from the air inlet to the air outlet; and
a rotor being rotatably supported by the bearing, the rotor having a hub surrounding the magnetic poles and having a profile substantially conforming a profile cooperatively formed by the magnetic poles, and a plurality of fan blades extending radially outwardly from the hub.
2. The electric fan as claimed in claim 1, wherein the lower portions are integrally formed with the upper portions.
3. The electric fan as claimed in claim 1, wherein the upper and lower portions of the magnetic poles are formed separately and then assembled together.
4. The electric fan as claimed in claim 3, wherein a tenon extends from one of the upper portion and the lower portion, and the other of the upper portion and the lower portion defines a mortise receiving the corresponding tenon therein.
5. The electric fan as claimed in claim 1, wherein the upper portions of the magnetic poles conform to one of truncated paraboloid profile and truncated cone profile.
6. The electric fan as claimed in claim 5, wherein the lower portions of the magnetic poles cooperatively form a cylinder-shaped profile.
7. The electric fan as claimed in claim 1, wherein the rotor further comprises a permanent magnet adhered to an inner wall of the hub, the hub and the permanent magnet each comprising an upper portion facing the upper portions of the magnetic poles, the upper portions of the hub and permanent magnet expanding radially along the direction from the air inlet to the air outlet.
8. A motor, comprising:
a stator having a stator core defining a central axis thereof, the stator core comprising a plurality of magnetic poles arranged around the axis and evenly spaced apart from each other, each magnetic pole comprising an upper portion and a lower portion, the upper portion extending aslant towards the central axis from the lower portion, stator coils wound around the stator for generating a magnetic field; and
a rotor being rotatably supported by the stator, the rotor having a permanent magnet thereon for generating a magnetic filed for interacting with the magnetic field generated by the stator coils.
9. The motor as claimed in claim 8, wherein the upper portions of the magnetic poles cooperatively form one of truncated paraboloid profile and truncated cone profile.
10. The motor as claimed in claim 8, wherein the lower portions of the magnetic poles cooperatively configure a cylinder-shaped profile.
11. The motor as claimed in claim 8, wherein the lower portions are formed integrally with the upper portions.
12. The electric fan as claimed in claim 8, wherein the upper and lowers portions are formed separately, a tenon extends from one of the upper portion and the lower portion, and the other of the upper portion and the lower portion defines a mortise receiving the corresponding tenon therein.
13. A motor for an electric fan comprising:
a stator comprising:
a stator core having a central cylinder, a plurality of radial posts extending radially outwardly from the central cylinder, a plurality of magnetic poles extending from free ends of the radial posts, respectively, and a plurality of stator coils wound around the radial posts, respectively, wherein the magnetic poles comprise lower portions cooperatively defining a cylindrical profile and a plurality of upper portions mounted on the lower portions, respectively, and cooperatively defining one of a truncated conic profile and a truncated paraboloid profile; and
a rotor rotatably mounted on the stator, having a hub and a magnet attached on the hub, the hub and the magnet surrounding the stator and having a profile conforming a profile cooperatively formed by the magnetic poles.
14. The motor as claimed in claim 13, wherein the upper portions of the magnetic poles each have a tenon inserted into a mortise defined in a corresponding lower portion of the magnetic pole.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A stent having a base body circumscribing a cylindrical shape and radially expandable from a contracted starting position into a dilated support position, comprising:
a) a plurality of struts, each strut comprising alternating curves separated by a straight segment, the struts being disposed in the circumferential direction and arrayed such that an inside zenith point of a first curve is aligned in the axial direction of the stent with an inside zenith point of a second curve on an adjacent strut, each strut being made of a flexible material; and
b) at least one axial connector in the axial direction, connecting the struts of the two axially adjacent curves;
wherein the at least one axial connector connects the inside radius of the zenith point of the first curve directly to the inside radius of the zenith point of the second curve;
wherein the at least one axial connector at the inside radius of the zenith point of the first curve has at least two arms forming an at least double-arm structure.
2. The stent according to claim 1, wherein the at least double-arm structure has two arms enclosing in the dilated support position an angle in the range of 30\xb0 to 180\xb0 between the two arms.
3. The stent according to claim 2, wherein the angle is in the range of 60\xb0 to 180\xb0 between the two arms.
4. The stent according to claim 3, wherein the angle is in the range of 90\xb0 to 180\xb0 between the two arms.
5. The stent according to claim 1, wherein the at least double-arm structure has three arms, wherein one arm, optionally the middle one, runs parallel to the axial direction.
6. The stent according to claim 1, wherein the flexible material is a material selected from the group consisting of metals, metal alloys and polymers.
7. The stent according to claim 1, wherein the flexible material is a biodegradable material.
8. The stent according to claim 7, wherein the biodegradable material is a material selected from the group consisting of magnesium, iron, zinc, tungsten and a metal alloy of any combination thereof.
9. The stent according to claim 1, wherein the at least one axial connector comprises a linear segment parallel to the axial direction of the stent.
10. The stent according to claim 9, wherein the linear segment comprises a double armed structure at each opposing end.