JP2008092702A5 - - Google Patents

Claims (13)

In the cross section perpendicular to the ring axis, the outer periphery of the ring is formed in a circular shape, and the inner periphery of the ring is periodically formed with recesses and protrusions in the circumferential direction,
N-pole and S-pole magnetic poles are alternately formed in the circumferential direction of the ring, and the boundary between the magnetic poles is formed in the concave portion having a thin magnet thickness . The concave portion extends over a predetermined length in the circumferential direction. A ring-type sintered magnet characterized in that the magnet thickness is substantially constant . In the region of the thick the convex portion of the magnet thickness, ring inner periphery is formed by convex curve, claims center of the magnetic pole is characterized in that it is arranged in the maximum magnet thickness portion of the convex portion 1 The ring-type sintered magnet described in 1. 3. The ring-type sintered magnet according to claim 2 , wherein the magnet thickness conforms to the following formula Lm (θ) in the region of the convex portion where the magnet is thick.
Lm (θ) ≈a / (1 / (k · sin θ) −1)
Here, Lm (θ): magnet thickness at a rotation angle θ with reference to a line connecting the center of the ring-type sintered magnet and the substantially center position in the circumferential direction of the recess.
a: Spacing of the air gap between the magnet outer circumference and the stator with respect to the maximum magnet thickness
k: Proportional constant between the amount of magnetic flux and magnetomotive force in the maximum magnet thickness region
k = Lm max · vm / ((Lm max + a) / μ0)
Lm max: Maximum magnet thickness
vm: Magnetomotive force per unit length of magnet
μ0: Permeability In the region of the thick the convex portion of the magnet thickness, ring inner periphery is formed in a convex angle shape in claim 1 in which the center of the magnetic pole is characterized in that it is arranged in the maximum magnet thickness portion of the convex portion The ring-type sintered magnet described. In the cross section perpendicular to the ring axis, the outer periphery of the ring is formed in a circular shape, and the inner periphery of the ring is periodically formed with S-curved convex portions and concave portions in the circumferential direction, and N poles and A ring-type sintered magnet in which the magnetic poles of S poles are alternately formed, the boundary of the magnetic poles is formed in the region of the recess having a thin magnet thickness, and the magnet thickness is continuously changed . In the cross section perpendicular to the ring axis, the outer periphery of the ring is formed in a circular shape, and the inner periphery of the ring is periodically formed with convex and concave portions of a quadratic curve in the circumferential direction, and the N pole and A ring in which S poles are alternately formed, a boundary between the poles is formed in a region of the recess having a small magnet thickness, and the recess is formed at a portion where the quadratic curve intersects. Mold sintered magnet. 2. The ring-type sintered magnet according to claim 1 , wherein the boundary of the magnetic pole is formed to be inclined in the ring axis direction in the region of the concave portion where the magnet is thin. The ring-type sintered magnet according to claim 7 , wherein the boundary of the magnetic pole is formed to be inclined in an S shape in the ring axis direction. The ring-type sintered magnet according to any one of claims 1 to 8 , and a convex portion and a concave portion that are substantially along the concave portion and the convex portion of the inner periphery of the ring-type sintered magnet. A rotor formed of an iron core formed and fixed to an inner peripheral portion of the ring-type sintered magnet, and a shaft to which the iron core is fixed. The gap between the ring sintered magnet and the iron core in the thin concave region is wider than the gap between the ring sintered magnet and the thick core. The rotor according to claim 9 . The rotor according to claim 9 , wherein a concave portion is provided in the iron core at a position corresponding to a concave region where the magnet thickness of the ring-type sintered magnet is thin. The rotor according to claim 11 , wherein the concave portion of the iron core is formed to be inclined with respect to the ring axis direction. A rotating machine comprising: the rotor according to any one of claims 9 to 12 ; and a stator disposed on an outer periphery of the rotor, wherein the rotor is rotatably supported with respect to the stator.