Passive dynamically stabilizing magnetic bearing and drive unit

• US 20060279149A1
• Filed: 04/11/2003
• Published: 12/14/2006
• Est. Priority Date: 05/16/2002
• Status: Abandoned Application

• Current Assignee: Silphenix GmbH
• Original Assignee: Silphenix GmbH
• Inventors: Asper, Hans K.
• Application Number:
  US10/514,612
• Publication Number:
  US 20060279149A1
• Time in Patent Office: Days
• US Class Current: 310/90.500
• CPC Class Codes: F16C 32/0436 with a conductor on one part movable with respect to a magnetic field, e.g. a body of copper on one part and a permanent magnet on the other part
• CPC Class Codes: H02K 7/09 with magnetic bearings

Abstract

The passive axial magnet bearing comprises permanent magnets (1, 2) arranged with alternating polarization on a rotor (1, 2, 8). These cause an oscillating flow through the coils (L) on both sides of the rotor (1, 2, 8). All coils (L) are series connected in an electric circuit (3). As long as the rotor (1, 2, 8) rotates in the middle position, no current flows in the electric circuit (3), since the voltages across the coils (L) cancel each other due to the symmetry. However, when the rotor (1, 2, 8) deviates from the center position, a current flows and the coils (L) exert electromagnetically a restoring force on the permanent magnets (1, 2). The bearing can also be equipped with an integrated drive. For this purpose, it is extended by drive coils. The production of the bearing is simple and inexpensive.

Claims

1-30. -30. (canceled)

31. Passive magnetic bearing, comprising magnets and bearing coils, wherein the magnets are moveable relatively to the bearing coils along at least one path, wherein the bearing coils are exposed to an oscillating magnetic flux due to the magnetic fields created by the magnets and are connected to each other in one or several electric circuits, wherein for each circuit applies that, when the magnets are moved along the path, the voltages induced by the oscillating magnetic flux in the bearing coils substantially cancel each other at any time and thereby no current flows and, when there is a deviation of the magnets from the path in direction of the polarization axis of the magnets, the voltages induced in the bearing coils do not cancel each other due to the changed distances from the magnets and the thereby changed strength of the magnetic flux such that a current flows and the bearing coils, which the current flows through, exert a restoring force on the magnets.

32. Passive magnetic bearing of claim 31, wherein the bearing coils are arranged on a first side of the path and on a second side of the path, which second side is opposite to the first side, and in each circuit at least one bearing coil of the first side of the path and at least one bearing coil of the second side of the path are connected by insertion.

33. Passive magnetic bearing of claim 31, wherein it is a radial bearing and comprises at least one circular path and the magnets as well as the bearing coils are oriented radially regarding their polarization axes.

34. Passive magnetic bearing of claim 31, wherein it is an axial bearing and comprises at least one circular path and the magnets as well as the bearing coils are oriented axially regarding their polarization axes.

35. Passive magnetic bearing of claim 34, wherein the bearing coils and the magnets have the same distance from the rotation axis.

36. Passive magnetic bearing of claim 34, wherein the magnets are arranged in a magnet plane or symmetrically to a magnet plane and a plurality of bearing coils are arranged on both sides of the magnet plane in two bearing coil planes, wherein the bearing coil planes are arranged symmetrically to the magnet plane.

37. Passive magnetic bearing of claim 31, wherein magnets, which are consecutive along the path, have a substantially parallel, however, regarding the sign opposing polarization.

38. Passive magnetic bearing of claim 31, wherein the magnets are distributed at equal distances along each path.

39. Passive magnetic bearing of claim 31, wherein all bearing coils are distributed at equal distances on circles parallel to the plane of the path.

40. Passive magnetic bearing of claim 38, wherein the distance between the center points of two neighboring bearing coils is equal to the distance between the center points of two neighboring magnets.

41. Passive magnetic bearing of claim 31, wherein it comprises pairs each with a first and a second bearing coil, wherein, in each case, the polarization axes of the first and the second bearing coil lie on the same straight line and in particular the first and the second bearing coil are connected to each other in the same electric circuit separate from further bearing coils.

42. Passive magnetic bearing of claim 31, wherein all bearing coils are series connected in a single electric circuit.

43. Passive magnetic bearing of claim 42, wherein the bearing coils are series connected and oriented in such a way that neighboring bearing coils on the same side of the path have, when there is a current flow, a substantially parallel, but regarding the sign opposing magnetic polarization.

44. Passive magnetic bearing of claim 31, comprising twice as many bearing coils as magnets.

45. Passive magnetic bearing of claim 31, wherein to each path the same number of magnets is assigned.

46. Passive magnetic bearing of claim 45, wherein the number of magnets is between ten and thirty.

47. Passive magnetic bearing of claim 31, wherein the magnets are moveable and the bearing coils are static.

48. Passive magnetic bearing of claim 31, wherein the magnets are static and the bearing coils are moveable.

49. Passive magnetic bearing of claim 31, wherein exactly one path is provided.

50. Passive magnetic bearing of claim 49, wherein the magnet bearing comprises two bearing coil holders and a magnet holder arranged in between.

51. Passive magnetic bearing of claim 31, wherein at least two paths are provided, wherein the paths run along coaxial circles.

52. Passive magnetic bearing of claim 51, wherein the paths lie in the same plane.

53. Passive magnetic bearing of claim 51, wherein the paths run along circles with equal diameter.

54. Passive magnetic bearing of claim 51, wherein it comprises at least two magnet holders and at least three bearing coil holders.

55. Passive magnetic bearing of claim 54, wherein each of the magnet holders is arranged between two bearing coil holders.

56. Passive magnetic bearing of claim 31, wherein it comprises means for shielding.

57. Passive magnetic bearing of claim 56, wherein the means for shielding are soft iron rings.

58. Passive magnetic bearing of claim 56, wherein the means for shielding are arranged such that the ends of the bearing coils, which are not directed towards a path, are covered by it.

59. Passive magnetic bearing of claim 31, wherein the magnets, in each case, are designed as two parts, i.e. consisting of two parts, wherein the two parts attract each other.

60. Passive magnetic bearing of claim 59, wherein a magnet holder comprises recesses on two sides opposing each other for receiving the parts of the magnets.

61. Passive magnetic bearing of claim 31, wherein the conductors of all bearing coils are of a material with finite conductivity.

62. Passive magnetic bearing of claim 31, wherein all bearing coils have the same number of windings, the same inductance and the same resistance.

63. Passive magnetic bearing of claim 31, wherein in at least one electric circuit an additional inductance is connected by insertion.

64. Passive magnetic bearing of claim 63, wherein the additional inductance is dimensioned such that in the electric circuit at a designated maximum rotation frequency of the bearing the phase shift between the voltage across a bearing coil and the current is substantially 90°

.

65. Magnetic bearing with drive which consists of a passive magnetic bearing of claim 31 and a drive, wherein the magnets serve for both, a bearing as well as a driving of the rotor.

66. Magnetic bearing with drive of claim 65, wherein the bearing comprises drive coils, which are arranged sideways of path in the magnetic fields created by the magnets.

67. Magnetic bearing with drive of claim 66, wherein the drive coils are, when viewed from the path, arranged behind the bearing coils.

68. Magnetic bearing with drive of claim 67, wherein the drive coils are directly adjacent to the bearing coils.

69. Magnetic bearing with drive of claim 66, wherein the drive coils are arranged on a first side of the path and on a second side of the path opposite to the first side.

70. Magnetic bearing with drive of claim 66, wherein the drive coils are arranged as pairs, wherein in each case drive coils arranged as a pair have polarization axes which lie on the same straight line.

71. Magnetic bearing with drive of claim 66, wherein it is an axial bearing, wherein the drive coils have polarization axes, which are substantially oriented axially.

72. Magnetic bearing with drive of claim 66, wherein the drive coils are arranged in one or two drive coil planes.

73. Magnetic bearing with drive of claim 72, wherein the drive coils are distributed at equal distances on one or, as the case may be, two circles, which are coaxial with an axis of the bearing.

74. Magnetic bearing with drive of claim 66, wherein the drive coils are connected to a power source.

75. Magnetic bearing with drive of claim 74, wherein the drive coils are connected to a current pulse generator.

76. Magnetic bearing with drive of claim 74, wherein the power source is controlled depending on a position and/or movement of the rotor.

77. Magnetic bearing with drive of claim 76 wherein for determining said position and/or movement an optical sensor and markings are provided on the rotor.

78. Magnetic bearing with drive of claim 66, wherein the drive coils are connected such and arranged relatively to the bearing coils such that a magnetic flux created by the individual drive coils through the bearing coils superposes and substantially cancels itself.

79. Magnetic bearing with drive of claim 78, wherein the bearing coils and the drive coils are arranged shifted relatively to each other by a phase angel of 90°

.

80. Magnetic bearing with drive of claim 66, wherein the drive coils are connected in a common electric circuit such that neighboring drive coils arranged on the same side of the path have, when there is a current flow, a substantially parallel, but regarding the sign opposing magnetic polarization and, as the case may be, drive coils on different sides of the path, the polarization axes of which lie on the same straight line, have an equally oriented magnetic polarization.