摘要:
In connection with a permanent magnet rotary machine comprising a rotor comprising a rotor core and a plurality of permanent magnet segments embedded in the rotor core and a stator comprising a stator core having a plurality of slots and windings therein, the rotor and the stator being disposed to define a gap therebetween, or a permanent magnet rotary machine comprising a rotor comprising a rotor core and a plurality of permanent magnet segments mounted on the surface of the rotor core and a stator comprising a stator core having a plurality of slots and windings therein, the rotor and the stator being disposed to define a gap therebetween, the rotor wherein each of the permanent magnet segments is an assembly of further divided permanent magnet pieces, and the coercive force near the surface of the magnet piece is higher than that in the interior of the magnet piece.
摘要:
In connection with a permanent magnet rotary machine comprising a rotor comprising a rotor core and a plurality of permanent magnet segments embedded in the rotor core and a stator comprising a stator core having a plurality of slots and windings therein, the rotor and the stator being disposed to define a gap therebetween, or a permanent magnet rotary machine comprising a rotor comprising a rotor core and a plurality of permanent magnet segments mounted on the surface of the rotor core and a stator comprising a stator core having a plurality of slots and windings therein, the rotor and the stator being disposed to define a gap therebetween, the rotor wherein each of the permanent magnet segments is an assembly of further divided permanent magnet pieces, and the coercive force near the surface of the magnet piece is higher than that in the interior of the magnet piece.
摘要:
In a rotating machine comprising a rotor including a rotor core and a plurality of permanent magnet segments, and a stator including a stator core and windings, the permanent magnet segment is obtained by disposing a powder comprising an R2 oxide, R3 fluoride or R4 oxyfluoride on a sintered magnet body of R1—Fe—B composition, wherein R1 to R4 are rare earth elements, and heat treating the powder-covered magnet body. The permanent magnet segment of a cross-sectional shape which is tapered from the center toward opposed ends has a higher coercive force at the ends than at the center.
摘要:
A rare earth permanent magnet is prepared from a sintered magnet body of a R1—Fe—B composition wherein R1 is a rare earth element inclusive of Y and Sc, by forming a plurality of slits in a surface of the magnet body, disposing a powder on the magnet body surface, the powder comprising an oxide of R2, a fluoride of R3, or an oxyfluoride of R4 wherein each of R2, R3, and R4 is a rare earth element, and heat treating the magnet body and the powder below the sintering temperature in vacuum or in an inert gas.
摘要:
A rare earth permanent magnet is prepared from a sintered magnet body of a R1—Fe—B composition wherein R1 is a rare earth element inclusive of Y and Sc, by forming a plurality of slits in a surface of the magnet body, disposing a powder on the magnet body surface, the powder comprising an oxide of R2, a fluoride of R3, or an oxyfluoride of R4 wherein each of R2, R3, and R4 is a rare earth element, and heat treating the magnet body and the powder below the sintering temperature in vacuum or in an inert gas.
摘要:
A method for preparing the magnet includes the steps of: (a) providing a sintered Nd base magnet block having surfaces and a magnetization direction, (b) coating the surfaces of the magnet block excluding the surface perpendicular to the magnetization direction with a Dy or Tb oxide powder, a Dy or Tb fluoride powder, or a Dy or Tb-containing alloy powder, (c) treating the coated block at a high temperature for causing Dy or Tb to diffuse into the block, and (d) cutting the block in a plane perpendicular to the magnetization direction into a magnet segment having a coercive force distribution on the cut section that the coercive force is high at the periphery and lower toward the inside and a constant coercive force distribution in the magnetization direction.
摘要:
The invention provides a sintered Nd base magnet which is free of a decline of remanence, has a high coercive force, especially at the edges thereof, is unsusceptible to demagnetization even at high temperature, and is suited for use in permanent magnet rotary machines.
摘要:
A method for preparing a rare earth permanent magnet material is characterized by comprising the steps of disposing a powder mixture on a surface of a sintered magnet body of R1—Fe—B composition wherein R1 is at least one element selected from rare earth elements inclusive of Sc and Y, the powder mixture comprising a powder containing at least 0.5% by weight of M which is at least one element selected from Al, Cu, and Zn and having an average particle size equal to or less than 300 μm and a powder containing at least 30% by weight of a fluoride of R2 which is at least one element selected from rare earth elements inclusive of Sc and Y and having an average particle size equal to or less than 100 μm, and heat treating the magnet body having the powder disposed on its surface at a temperature equal to or below the sintering temperature of the magnet body in vacuum or in an inert gas, for causing at least one of M and R2 in the powder mixture to be absorbed in the magnet body. The invention provides an R—Fe—B sintered magnet with high performance and a minimized amount of Tb or Dy used.
摘要:
A permanent magnet material is prepared by covering an anisotropic sintered magnet body of formula: R1x(Fe1-yCoy)100-x-z-aBzMa wherein R1 is a rare earth element, M is Al, Cu or the like, with a powder comprising an oxide of R2, a fluoride of R3 or an oxyfluoride of R4 wherein R2, R3, and R4 are rare earth elements, and having an average particle size up to 100 μm, heat treating the powder-covered magnet body in a hydrogen gas-containing atmosphere for inducing disproportionation reaction on R12Fe14B compound, and continuing heat treatment at a reduced hydrogen gas partial pressure for inducing recombination reaction to said compound, thereby finely dividing said compound phase to a crystal grain size up to 1 μm, and for effecting absorption treatment, thereby causing R2, R3 or R4 to be absorbed in the magnet body.
摘要:
A rare earth permanent magnet is in the form of a sintered magnet body having a composition R1aR2bTcAdFeOfMg wherein F and R2 are distributed such that their concentration increases on the average from the center toward the surface of the magnet body, the concentration of R2/(R1+R2) contained in grain boundaries surrounding primary phase grains of (R1,R2)2T14A tetragonal system within the sintered magnet body is on the average higher than the concentration of R2/(R1+R2) contained in the primary phase grains, and the oxyfluoride of (R1,R2) is present at grain boundaries in a grain boundary region that extends from the magnet body surface to a depth of at least 20 μm. The invention provides R—Fe—B sintered magnets which exhibit high magnet performance despite minimal amounts of Tb and Dy used.