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.

This application provides a motor rotor, including a rotor iron core and a plurality of permanent magnets disposed on the rotor iron core. Coercive forces of at least some permanent magnets are continuously gradiently distributed or gradiently distributed in a multi-stage manner from the middle to both ends along at least one direction perpendicular to a magnetization direction. The permanent magnet with a gradient coercive force design is used in the motor rotor. A coercive force of the permanent magnet is continuously gradiently distributed or gradiently distributed in a multi-stage manner from the middle to both ends. In this way, a coercive force change of the entire permanent magnet is uniform, and stability and reliability of the motor can be maximized. In addition, this can avoid excessive anti-demagnetization performance, reduce an amount of usage of heavy rare earth elements, and minimize costs of the motor.

Provided are molds for polar anisotropic ring-shaped bonded magnet molded articles which enable the production of bonded magnet molded articles with a high degree of roundness and only slight distortion, without the need for mold modification and preparation of a test mold, and a method of preparing such molds. The present invention relates to a method of preparing a mold for a polar anisotropic ring-shaped bonded magnet molded article, the method including: 1) determining the shrinkage length (Tc) of a desired polar anisotropic ring-shaped bonded magnet molded article using the following equation: Tc=T×(α1/100−α2/100); 2) determining the radius (Dm) of a magnetic pole portion of a mold cavity using the following equation: Dm=D/(1−α2/100); and 3) defining the outer peripheral shape of the mold cavity from the Tc, the Dm, and the number (P) of magnetic poles of the molded article.

A method for producing a radially anisotropic sintered ring magnet by continuously repeating a step of supplying magnetic powder to a die comprising a columnar magnetic core, and a cylindrical outer die having axially connected magnetic member and non-magnetic member, with a cavity between the core and the cylindrical outer die, and a step of compression-molding the magnetic powder in a radial magnetic field applied between the magnetic core and the magnetic member of the outer die, plural times in one die, to form a final green body composed of pluralities of integrally connected green bodies; and sintering the final green body; the magnetic field being applied in a state where an upper end of the magnetic member of the cylindrical outer die is higher than an upper surface of the magnetic powder supplied.

A sintered annular magnet with a radial orientation of a remanent magnetic field, including: a principal annular part made from a ferromagnetic material, that has a first degree of magnetic anisotropy in the radial direction; and an annular reinforcing part fixed to the principal part of the magnet, the reinforcing part being made from same ferromagnetic material as the ferromagnetic material forming the principal part, and that has a second degree of magnetic anisotropy in the radial direction, the first degree being higher than the second degree.

A bond magnet includes filaments bonded with each other to form a shape of the bond magnet. Each of the filaments is a filamentous member including a resin material and magnetic powder dispersed in the resin material, and has magnetic anisotropy for high degree of freedom of magnetic flux direction and high surface magnetic flux density on a working surface.

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 rotor includes at least one first permanent magnet and at least one second permanent magnet. The at least one first permanent magnet forms part of an outer peripheral surface of the rotor and is magnetized to have polar anisotropy. The at least one second permanent magnet is adjacent to the at least one first permanent magnet in a circumferential direction of the rotor and has lower magnetic force than magnetic force of the at least one first permanent magnet.

A rotor includes at least one first permanent magnet and a second permanent magnet and has 2n (n is a natural number) magnetic poles. The at least one first permanent magnet forms part of an outer peripheral surface of the rotor and is magnetized to have polar anisotropy. The second permanent magnet is adjacent to the at least one first permanent magnet in a circumferential direction of the rotor, and has lower magnetic force than magnetic force of the at least one first permanent magnet. The second permanent magnet has 3×2n magnetic poles.

Provided are molds for polar anisotropic ring-shaped bonded magnet molded articles which enable the production of bonded magnet molded articles with a high degree of roundness and only slight distortion, without the need for mold modification and preparation of a test mold, and a method of preparing such molds. The present invention relates to a method of preparing a mold for a polar anisotropic ring-shaped bonded magnet molded article, the method including: 1) determining the shrinkage length (Tc) of a desired polar anisotropic ring-shaped bonded magnet molded article using the following equation: Tc=T×(α1/100−α2/100); 2) determining the radius (Dm) of a magnetic pole portion of a mold cavity using the following equation: Dm=D/(1−α2/100); and 3) defining the outer peripheral shape of the mold cavity from the Tc, the Dm, and the number (P) of magnetic poles of the molded article.