This invention provides for a rotary electric machine that includes a rotor having a plurality of permanent magnets arranged in the circumferential direction, and in which the leakage of magnetic flux can be suppressed with a simple structure; and a rare-earth permanent magnet-forming sintered compact for forming rare-earth permanent magnets to be used in said rotary electric machine.

Provided are a rare-earth magnet capable of realizing a high magnetic flux amount without using any back yoke, and a linear motor comprising a movable element using the rare-earth permanent magnet. A rare-earth permanent magnet-forming sintered body for forming a permanent magnet is integrally sintered while being formed into a given three-dimensional shape with a lengthwise cross-section having a first surface extending in a length direction thereof, a second surface lying at a distance from the first surface in a thickness direction thereof and extending in the length direction, and an edge surface of each of lengthwise opposite ends thereof. This sintered body is formed such that easy magnetization axes of the magnet material particles included in a central region thereof are oriented in such a manner as to be directed along an arch-shaped path.

A production method for an anisotropic bonded magnet includes: filling the annular cavity with a magnet raw material including one or more types of rare-earth anisotropic magnet powder and a binder resin; applying aligning magnetic fields to the magnet raw material being aligned in the softened or molten binder resin, the aligning magnetic fields are applied from an even number of aligning magnetic pole bodies arranged around outer periphery of the annular cavity such that directions of magnetic fields are alternated; subjecting the magnet raw material to a molding to form a compact; rotating the aligning magnetic pole bodies in circumferential direction for a predetermined angle; and applying demagnetization magnetic fields to the compact from the aligning magnetic pole bodies during the alignment step. The demagnetization magnetic fields are in directions for cancelling magnetization of the compact caused by the aligning magnetic fields.

A production method for an anisotropic bonded magnet includes: filling the annular cavity with a magnet raw material including one or more types of rare-earth anisotropic magnet powder and a binder resin; applying aligning magnetic fields to the magnet raw material being aligned in the softened or molten binder resin, the aligning magnetic fields are applied from an even number of aligning magnetic pole bodies arranged around outer periphery of the annular cavity such that directions of magnetic fields are alternated; subjecting the magnet raw material to a molding to form a compact; rotating the aligning magnetic pole bodies in circumferential direction for a predetermined angle; and applying demagnetization magnetic fields to the compact from the aligning magnetic pole bodies during the alignment step. The demagnetization magnetic fields are in directions for cancelling magnetization of the compact caused by the aligning magnetic fields.

Raw material magnet is milled to magnet powder, and the magnet powder thus milled is mixed with a binder to form a compound 12. Then, the compound 12 thus formed is molded to a green sheet 14 having a sheet shape. Thereafter, a magnetic field orientation is carried out by applying a magnetic field to the green sheet 14 thus molded, and then, the green sheet 14 having been subjected to the magnetic field orientation is shaped to a product shape by deforming thereof. Thereafter, the permanent magnet 1 is produced by sintering thereof. The permanent magnet 1 has a ring shape, and is constituted such that an axis of easy magnetization may be orientated at a slant so as to converge in a direction along a converging axis P which is set to a radius direction as well as to a center direction of the ring shape.

A method for production of an anisotropic bonded magnet includes: aligning magnetic pole bodies which include an even number of permanent magnets arranged uniformly around an outer periphery of an annular cavity filled with magnetic raw material, aligning magnetic fields to cause rare-earth anisotropic magnet powder to be semi-radially aligned; compressively molding the semi-radially aligned magnet raw material to obtain an annular compact; discharging the compact from the annular cavity; demagnetizing causing the aligning magnetic pole bodies to relatively move only in circumferential direction with respect to the compact after the molding step thereby to apply demagnetization magnetic fields to the compact; The demagnetization magnetic fields are applied from the aligning magnetic pole bodies with opposite poles to those during the alignment step, and the demagnetization magnetic fields are in directions for cancelling the magnetization of the compact caused by the aligning magnetic fields.

In a method for manufacturing a cylindrical bonded magnet, a molding space having a cylindrical shape is filled with a bonded magnet composition containing a magnetic material and a resin. The magnetic material disposed in the molding space is magnetically oriented using an orientation magnet. The orientation magnet includes a first permanent magnet and a second permanent magnet. The first and second permanent magnets are disposed such that same poles are opposite each other in the axial direction.

A method of manufacturing a polar anisotropic magnet includes manufacturing polar anisotropic magnets 1N, 1S having four surfaces SF1, SF2, SF3. The method includes: an in-field molding step S20 for performing molding in a magnetic field while applying a magnetic field in a first direction of one effective surface VSF (SF1) among the four surfaces and applying a magnetic field in a second direction to the remaining three surfaces (SF2, SF3, SF4); and a four-way magnetization step S40 for performing magnetization by applying a magnetic field in the first direction to the effective surface VSF (SF1) and by applying a magnetic field in the second direction to the remaining three surfaces (SF2, SF3, SF4). The present invention provides a method of manufacturing a polar anisotropic magnet and a method of manufacturing a magnet assembly that have a higher degree of freedom in designing and are more economical than other approaches.

A method for continuous manufacture of permanent magnets. A material sheet is formed into an open tube, having a lengthwise opening. Magnetic powder may be poured into the lengthwise opening on a continuous basis. The tube opening is then formed closed and sealed. The magnetic powder is magnetically pre-aligned by subjecting it to a first magnetic field. The tube containing the powder may be compressed into a desired shape, forming an elongated permanent magnet. After compression, the elongated magnet is magnetized by a second magnetic field in two-step process, wherein the elongated permanent magnet is subjected to a magnetic field from first magnetizing coil that is pulsed with a first electric current in a first direction, followed by a second magnetizing coil being pulsed with a second magnetizing electric current in a second direction. The elongated magnet may be formed into any arbitrary shape, such as a ring or coil.