Abstract: In a permanent magnet type electric rotating machine, a rotor is arranged in a Halbach array, a main magnet magnetized in the radial direction is formed of a rare-earth magnet and an auxiliary magnet magnetized in the circumferential direction is formed of a ferrite magnet, and a gap is provided between the main magnet and the auxiliary magnet; as a result, the quantity of utilized rare-earth magnets is reduced without the output torque of the electric rotating machine being decreased.

Abstract: To provide a magnetic encoder in which a base material has a ring-shaped body portion into which a rotation axis is inserted when a magnetic drum is mounted on a rotation axis, and an engagement convex portion provided so as to project over a whole circumference of an outer periphery of the body portion. The body portion has a centering track provided in a part of the outer periphery of the body portion over the whole circumference as a reference of circular runout tolerance on an outer periphery of a magnet. The engagement convex portion has a constricted portion projecting from the outer periphery of the body portion, and a cylindrical portion extending in an axial direction of the body portion from a tip end of the constricted portion. The magnet surrounds the engagement convex portion so as to wrap around to a gap between the cylindrical portion and the body portion, and exposes the centering track without covering the centering track.

Abstract: To provide a magnetic encoder in which a base material has a ring-shaped body portion into which a rotation axis is inserted when a magnetic drum is mounted on a rotation axis, and an engagement convex portion provided so as to project over a whole circumference of an outer periphery of the body portion. The body portion has a centering track provided in a part of the outer periphery of the body portion over the whole circumference as a reference of circular runout tolerance on an outer periphery of a magnet. The engagement convex portion has a constricted portion projecting from the outer periphery of the body portion, and a cylindrical portion extending in an axial direction of the body portion from a tip end of the constricted portion. The magnet surrounds the engagement convex portion so as to wrap around to a gap between the cylindrical portion and the body portion, and exposes the centering track without covering the centering track.

Abstract: In a permanent magnet type electric rotating machine, a rotor is arranged in a Halbach array, a main magnet magnetized in the radial direction is formed of a rare-earth magnet and an auxiliary magnet magnetized in the circumferential direction is formed of a ferrite magnet, and a gap is provided between the main magnet and the auxiliary magnet; as a result, the quantity of utilized rare-earth magnets is reduced without the output torque of the electric rotating machine being decreased.

Abstract: A wire rope flaw detector includes a magnetizer having a pair of exciting magnets disposed on a back yoke such that polarities thereof are opposite to each other, and forming a main magnetic path in a predetermined segment in an axial direction of a wire rope; and a leakage magnetic flux detection section disposed in the predetermined segment in the axial direction, and detecting leakage magnetic flux generated from a damaged portion of the wire rope. Each of the exciting magnets are formed so as to have a cross-section of a shape that embraces the wire rope when each exciting magnet is cut along a plane perpendicular to the axial direction of the wire rope, and has magnetic orientation, on the cross-section of the exciting magnet, oriented from at least two directions toward the wire rope.

Abstract: A wire rope flaw detector includes a magnetizer having a pair of exciting magnets disposed on a back yoke such that polarities thereof are opposite to each other, and forming a main magnetic path in a predetermined segment in an axial direction of a wire rope; and a leakage magnetic flux detection section disposed in the predetermined segment in the axial direction, and detecting leakage magnetic flux generated from a damaged portion of the wire rope. Each of the exciting magnets are formed so as to have a cross-section of a shape that embraces the wire rope when each exciting magnet is cut along a plane perpendicular to the axial direction of the wire rope, and has magnetic orientation, on the cross-section of the exciting magnet, oriented from at least two directions toward the wire rope.

Abstract: Radially oriented ring-shaped preliminarily molded pieces of a ring magnet are stacked in an axial direction to form a ring-shaped molded body, in which end faces of the ring-shaped preliminarily molded pieces are bonded together. This ring-shaped molded body is sintered and heat-treated to produce the ring magnet. Ring magnets which are less susceptible to deterioration of magnetic properties due to a disturbance of magnetic orientation near lamination boundary surfaces are produced. The invention provides a method of manufacturing such ring magnets with high efficiency.

Abstract: An apparatus for manufacturing a ring-shaped powder compact (100) includes a ring-shaped die (80) having magnetic property formed by combining a plurality of arch-shaped members (81, 82, 83, 84), a lower core section (93) placed inside a curved inner surface of the die (80), and lower and upper punches (91, 92) for pressurizing both the die (80) and magnetic powder filled into a cavity formed between the die (80) and the lower core section (93) in an axial direction of the die (80). The curved inner surface of the die (80) varies in cross-sectional shape from one position to next along the axial direction of the die (80) at least in part along the axial direction.

Abstract: This invention relates to a permanent magnet molding apparatus and has as an object an improvement in productivity and reliability thereof.

Abstract: Radially oriented ring-shaped preliminarily molded pieces of a ring magnet are stacked in an axial direction to form a ring-shaped molded body, in which end faces of the ring-shaped preliminarily molded pieces are bonded together. This ring-shaped molded body is sintered and heat-treated to produce the ring magnet. Ring magnets which are less susceptible to deterioration of magnetic properties due to a disturbance of magnetic orientation near lamination boundary surfaces are produced. The invention provides a method of manufacturing such ring magnet with high efficiency.

Abstract: An apparatus for manufacturing a ring-shaped powder compact (100) includes a ring-shaped die (80) having magnetic property formed by combining a plurality of arch-shaped members (81, 82, 83, 84), a lower core section (93) placed inside a curved inner surface of the die (80), and lower and upper punches (91, 92) for pressurizing both the die (80) and magnetic powder filled into a cavity formed between the die (80) and the lower core section (93) in an axial direction of the die (80). The curved inner surface of the die (80) varies in cross-sectional shape from one position to next along the axial direction of the die (80) at least in part along the axial direction.

Abstract: A sintered ring magnet (10) is produced through processes of magnetically orienting magnetic powder by applying a magnetic field, pressing the magnetic powder and sintering a ring-shaped powder compact (30) thus formed. The sintered ring magnet (10) has a generally cylindrical outer surface with surface corrugations formed by alternating hollows (11) and protrusions (12) at regular intervals around the sintered ring magnet (10) at least in part along an axial direction thereof, wherein the sintered ring magnet (10) varies in cross-sectional shape from one position to next along the axial direction, and magnetic poles are formed along the surface corrugations with boundaries of the magnetic poles located in the hollows (11). The hollows (11) and the protrusions (12) are skewed about a longitudinal axis of the sintered ring magnet (10). The surface corrugations are shaped into a wavy pattern expressed approximately by absolute values of a sine wave.

Abstract: A ring magnet manufacturing method includes the steps of stacking a plurality of radially oriented ring-shaped powder compacts (102) in an axial direction thereof to produce a ring-shaped powder compact rod, sintering the ring-shaped powder compact rod to produce a sintered ring-shaped powder compact rod (300) in which the ring-shaped powder compacts (102) are joined together, and dividing the sintered ring-shaped powder compact rod (300). In this ring magnet manufacturing method, protruding parts (103) are formed on upper end surfaces of the ring-shaped powder compacts (102) which will be located in uppermost layers of individual sintered ring magnets (100), for example, such that the ring-shaped powder compacts (102) are joined with a reduced joint strength at specific boundary regions of the sintered ring-shaped powder compact rod (300) where the protruding parts (103) are located than at the other boundary regions.

Abstract: This invention relates to a permanent magnet molding apparatus and has as an object an improvement in productivity and reliability thereof.

Abstract: A polarizing device includes: a polarizing iron core (13) facing to a specified number of permanent magnets (11) among plural unmagnetized permanent magnets (11) arranged at specified intervals circumferentially on a rotor (12); a first coil (15) wound at a position facing to a desired permanent magnet (11a) of the polarizing iron core (13); a pair of second coils (16) each arranged having a specified interval according to the first coil (15) circumferentially on the polarizing iron core (13) and whose direction of the flowing current is different from that of the first coil (15); and a power source (22) for supplying the current to the first and second coils (15, 16), and either of the permanent magnet (11a) and first coil (15) is relatively moved and each permanent magnet (11) is magnetized to form a magnetic pole in turn by the current fed from the power source (22).

Abstract: A polarizing device includes: a polarizing iron core (13) facing to a specified number of permanent magnets (11) among plural unmagnetized permanent magnets (11) arranged at specified intervals circumferentially on a rotor (12); a first coil (15) wound at a position facing to a desired permanent magnet (11a) of the polarizing iron core (13); a pair of second coils (16) each arranged having a specified interval according to the first coil (15) circumferentially on the polarizing iron core (13) and whose direction of the flowing current is different from that of the first coil (15); and a power source (22) for supplying the current to the first and second coils (15, 16), and either of the permanent magnet (11a) and first coil (15) is relatively moved and each permanent magnet (11) is magnetized to form a magnetic pole in turn by the current fed from the power source (22).