Abstract: The present invention provides a rotor for motors, in which motor torque is kept high and generation of torque ripples is reduced, and what is more, detecting accuracy of a magnetic pole position is not deteriorated. The present invention provides a rotor assembly having a first divided rotor magnetic pole unit 15 and a second divided rotor magnetic pole unit 17 are disposed side by side on a surface of a rotor core 13 in an axial direction of a rotary shaft 11. The first divided rotor magnetic pole unit 15 includes P (P is a positive even number) permanent magnet magnetic pole portions 21 of a first kind and P (P is the positive even number) salient pole portions 23 made of a magnetic material, which are alternately disposed in a circumferential direction of the rotary shaft 11.

Abstract: Provided is a rotating electric machine which can restrain vibration and noise induced by a radial electromagnetic force of the rotating electric machine, and in which a rotor is divided into first to fourth four rotating pieces having axial lengths of 0.29L, 0.71L, 0.71L and 0.29L where 2L is an axial length of a rotor or stator core, and secondary conductors defining effective magnetic pole opening angles, are arranged being shifted by a value which is equal to a phase difference of electric angle between axial sections of the rotor pieces in order to define skews so that phase differences of electric angles are continuous between axial sections of the first and second rotor pieces, the skews being continuous between the third and fourth rotor pieces but being not continuous between the second and third rotor pieces arranged being shifted by a value which is equal to a phase difference of electric angle between axial sections of the rotor.

Abstract: Synchronous motors according to the invention operate at higher efficiency, with lower cost, reduced mass and reduced cogging. Magnet dimensions are selected that reduce cogging forces to a negligible amount even though there are fewer slots than normal. Optionally, it is possible to use non-overlapping windings with deeper and open slots. The approach is applicable to both rotary and linear motors and motors using either permanent magnets or electromagnets in the field structure. It is particularly relevant to linear or rotary motors that have a large air gap, and to small motors that must deliver a high ratio of thrust or torque to motor mass.

Abstract: 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.

Abstract: The vibration and noise excited by the electromagnetic exciting force in the radial direction of an electric motor are suppressed. In an electric motor 100, a rotor 1 is divided into four rotor pieces 3, 4, 5, and 6 for an axial length of 2L of one group of the rotor core, and for example, the four rotor pieces 3, 4, 5, and 6 are ideally 0.29L, 0.71L, 0.71L, and 0.29L in axial length in the axial direction, and permanent magnets 2 of the rotor pieces 3, 4, 5, and 6 are arranged in the circumferential direction so that the phase differences of the electrical angle are 0, ?, 0, and ?. Further, when an effect is obtained even if the ideal axial length is changed, the tolerance of the aforementioned axial length is ±0.1L.

Abstract: To easily manufacture an encoder, in which N-poles and S-poles of magnets are arranged alternately in a circumferential direction and in which an unequal pitch portion is provided in a part on a circumference, without using a magnetizing head of a special shape having an unequal pitch portion, the unequal pitch portion is formed by arranging the N-poles and the S-poles at an equal pitch all over the circumference and then providing a part on the circumference with a shielding member for shielding a magnetism. Alternatively, the unequal pitch portion is formed by arranging the N-poles and the S-poles at an equal pitch all over the circumference and then providing a part on the circumference with a cut portion.

Abstract: The present invention provides a technique for enabling permanent magnets constituting the field magnet system of an IPM electric rotating machine to be embedded in a rotor core in a shallower depth. The IPM electric rotating machine is composed of a stator and a rotor. The rotor includes a rotor core and permanent magnets constituting the field magnet system. The rotor core has a side face opposed to the stator, and the permanent magnets are shallowly embedded so that the distance between the pole face thereof and the rotor side face is reduced. Furthermore, two adjacent permanent magnets are intensively spaced so that the following formula holds: 0.3<(Lq?Ld)/Ld, where Lq is the q-axis inductance of the rotor, and Ld is the d-axis inductance thereof.

Abstract: A permanent magnet synchronous motor includes a rotor having cage windings and permanent magnets placed on an inner peripheral side of these cage winding bars, where the permanent magnets are placed and polarized so that a ratio ?/? between a circumferential pitch angle ? of magnetic flux distribution of the permanent magnets and a magnet pole pitch angle ? is between 0.67 and 0.91.

Abstract: In a permanent magnet motor consisting of a rotor 1, which is supported on a rotating shaft 2 and has twelve permanent magnets 3 arranged at fixed intervals in the circumferential direction in the peripheral edge portion thereof, and a stator 4, which is disposed around the rotor 1 with a gap being provided with respect to the rotor 1 and has nine magnetic poles 4a, each having a coil wound thereon, arranged at fixed intervals in the circumferential direction so as to face towards the outer peripheral surface of the rotor 1, a value obtained by dividing the radius of the rotor 1 by the radius of curvature of a permanent magnet surface facing towards the stator is set at a value such as to decrease cogging torque.

Abstract: A permanent magnet rotating electric machine uses no skewing under a predetermined current and voltage condition to prevent torque from decreasing and to decrease pulsation torque to make the machine less vibrating and less noisy. The permanent magnet rotating electric machine includes a stator with multi-phase stator windings and a rotor with a plurality of permanent magnets internally embedded in a rotor core. The core shape of the rotor is uniform in the depth (longitudinal) direction with no skewing in the arrangement of the permanent magnets. The permanent magnets are symmetrical with respect to the rotation direction, but irregular with respect to the depth direction, for each pole. A magnetic flux generated from the between-pole permanent magnets almost equals a magnetic flux generated from the pole-center permanent magnet.

Abstract: The present invention provides a permanent-magnet-synchronous-motor having a stator with concentrated windings with the following structure so that permanent magnet (6) is hard to subjected to demagnetization magnetic field: 0.3 Lg<La?2.0 Lg, where La is a clearance between teeth of stator (1), and Lg is an air-gap between stator (1) and rotor (2). Outer walls of both ends of the permanent magnet (6) disposed within rotor (2) in a rim direction may be tapered toward inside from a rotor rim in a radial direction and to form a recessed section on the outer walls of the magnets. As a result, withstanding force against demagnetization is expected to increase.

Abstract: The present invention provides a permanent-magnet-synchronous-motor having a stator with concentrated windings with the following structure so that permanent magnet (6) is hard to subjected to demagnetization magnetic field: 0.3 Lg<La?2.0 Lg, where La is a clearance between teeth of stator (1), and Lg is an air-gap between stator (1) and rotor (2). Outer walls of both ends of the permanent magnet (6) disposed within rotor (2) in a rim direction may be tapered toward inside from a rotor rim in a radial direction and to form a recessed section on the outer walls of the magnets. As a result, withstanding force against demagnetization is expected to increase.

Abstract: A rotary electric machine includes a rotor including a plurality of magnet sections arranged along a rotational direction of the rotor so that polarities of the magnet sections change alternately, and a stator including armature coils, and being disposed to confront the rotor across an air gap. Permanent magnet flux which is not linked with one of the air gap and the armature coils is higher than permanent magnet flux which is linked with the air gap and the armature coils in a no-load state.

Abstract: A permanent magnet motor having a rotor and a stator and configured such that when the leading edge of each pole of the rotor aligns with a stator tooth the trailing edge of that pole is generally not aligned with a stator tooth.

Abstract: This abstract section is written to explain this patent application. A magnetic motion has been found utilizing the sides and corners of permanent magnets. This motion has been taught at public schools by myself and the magnetic motion at certain angles continues to perform without fail. The intent of this inventor is to continue to develop and teach this magnetic motion and the set-up to achieve this motion. An engine/motor capable of picking up a load, while under a load is the final goal of this effort. This patent is for a magnetic motion, a magnetic motion demonstrator, and a teaching tool itself. Any future engines/motors using this method of magnetic motion will fall under this patent in the fundamental's area only not in the individual improvements of future patents. If allowed, an itemized list of non-patent-able fundamentals/techniques will be included.

Abstract: At each permanent magnet in a rotor of an IPM rotary electric machine, each of a pair of flux barriers respectively disposed adjoining circumferentially opposed side faces of the magnet is formed with a trench portion that extends farther from a circumferential face of the rotor than a position on a corresponding side face that is located farthest, on that side face, from the rotor circumferential face. This prevents part of a flow of magnetic flux, from the stator through the rotor, from being diverted to flow into the magnet. Increased torque or output power is thereby achieved.

Abstract: A permanent magnet machine comprises a stator having plurality of slots between a plurality of stator teeth, which are interconnected by a yoke, wherein concentrated windings are provided in the plurality of slots. A rotor is provided with a plurality of permanent magnets creating a plurality of magnetic poles. By giving the machine a relation between the number of slots and the number of poles that is given by Q=p+?2, wherein Q is the number of slots and p is the number of poles, low ripple torque and high torque density are obtained, particularly for servo applications.

Abstract: The present invention provides a rotor for motors, in which motor torque is kept high and generation of torque ripples is reduced, and what is more, detecting accuracy of a magnetic pole position is not deteriorated. A first divided rotor magnetic pole unit 15 and a second divided rotor magnetic pole unit 17 are disposed side by side on a surface of a rotor core 13 in an axial direction of a rotary shaft 11. The first divided rotor magnetic pole unit 15 includes P (P is a positive even number) permanent magnet magnetic pole portions 21 of a first kind and P (P is the positive even number) salient pole portions 23 made of a magnetic material, which are alternately disposed in a circumferential direction of the rotary shaft 11. The second divided rotor magnetic pole unit 17 includes P (P is the positive even number) permanent magnet magnetic pole portions 25 of a second kind which are spaced on another part of the surface of the rotor core 13 in the circumferential direction of the rotary shaft 11.

Abstract: A brushless motor including a rotor which has ten permanent magnets each containing rare earth neodymium and provided around a rotor yoke and an outside diameter of 45 mm to 55 mm, and a stator which has a stator core having twelve slots and an outside diameter of 75 mm to 85 mm and whose magnetomotive force at maximum current is 700 AT or more. The stator core is configured such that a teeth width b is 0.14 times or more of the outside diameter of the rotor.

Abstract: A plurality of convex portions are located inside of a virtual circumferential surface. Each convex portion connects an adjacent pair of circumferential portions with each other. Each convex portion is an arcuate curve bulging radially outward. Each convex portion defines a minimum radius. A difference between a radius R and the minimum radius is a depth Dh. Dhr=Dh×25.5/R. A range of an angular width A in relation to circumferential portion and a range of the depth Dh are set by the following expression, (5.6×Dhr+11.3)°×6/p?A<35°×6/p and A<[360/p?2×arccos]° ??(1) Therefore, decrease in torque is prevented. Torque pulsation is suppressed.

Abstract: A permanent magnet rotating electric machine uses no skewing under a predetermined current and voltage condition to prevent torque from decreasing and to decrease pulsation torque to make the machine less vibrating and less noisy. The permanent magnet rotating electric machine includes a stator with multi-phase stator windings and a rotor with a plurality of permanent magnets internally embedded in a rotor core. The core shape of the rotor is uniform in the depth (longitudinal) direction with no skewing in the arrangement of the permanent magnets. The permanent magnets are symmetrical with respect to the rotation direction, but irregular with respect to the depth direction, for each pole. A magnetic flux generated from the between-pole permanent magnets almost equals a magnetic flux generated from the pole-center permanent magnet.

Abstract: A permanent magnet rotating electric machine uses no skewing under a predetermined current and voltage condition to prevent torque from decreasing and to decrease pulsation torque to make the machine less vibrating and less noisy. The permanent magnet rotating electric machine includes a stator with multi-phase stator windings and a rotor with a plurality of permanent magnets internally embedded in a rotor core. The core shape of the rotor is uniform in the depth (longitudinal) direction with no skewing in the arrangement of the permanent magnets. The permanent magnets are symmetrical with respect to the rotation direction, but irregular with respect to the depth direction, for each pole. A magnetic flux generated from the between-pole permanent magnets almost equals a magnetic flux generated from the pole-center permanent magnet.

Abstract: An electrically-driven fan 1 comprises a base portion 2; a bearing portion 11; a stator 13 including iron core portions 15 and coils 16; a rotor 4 including a rotary shaft 20 and a cylindrical magnet 22; blowing blades 5; and a rotor position detector 23 which is disposed on a side of the cylindrical magnet 22 near to the base portion 2, with a gap of predetermined width relative to the cylindrical magnet 22; wherein the cylindrical magnet 22 includes a thin-walled portion 24 in which an effective thickness of one end part thereof near to the rotor position detector 23 is made smaller than an effective thickness of the other end part thereof.

Abstract: A synchronous electric machine includes a stator and a rotor. The stator is provided with teeth, which are wound around to establish electromagnetic fields. The rotor is provided with permanent magnets to generate magnetic fields, so that the rotor can rotate by interaction of the magnetic fields of the windings and the permanent magnets of the magnets. At least one pair of the permanent magnets is dislocated by a predetermined angle from positions where the permanent magnets is arranged at even pitch, and the predetermined angle being set to reduce electromagnetic excitation force acting on said teeth.

Abstract: A total of three permanent magnets, installed in a rotor core closely to an outer cylindrical surface of the rotor core, are disposed at predetermined angular pitches in the circumferential direction of the rotor core. All of the permanent magnets are magnetized in such a manner that the direction of magnetization is the same when seen in the radial direction. A plurality of magnet-less holes, extending in the axial direction in the vicinity of the outer cylindrical surface of the rotor core, are provided between two adjacent permanent magnets.

Abstract: A cored motor includes a rotor (21), having a rotor hub (2), a shaft (1) fixed to the rotor hub (2), a rotor yoke (5) in ring shape and a ring magnet (6) fixed to an inner circumferential surface of the rotor yoke (5). A stator (3) has a motor base (13) and a stator core (14) and a sleeve (9) in cylindrical shape fixed to the motor base (13) respectively. A surface of the rotor hub (2) in the motor base side is provided with a recessed portion (23) having an annular shape and a raised portion (24) that protrudes continuously or intermittently in an annular shape. The rotor yoke (5) is fixed to the recessed portion (23) and the ring magnet (6) contacts the raised portion (24) and fixed to the rotor yoke (5). Respective center lines of the rotor yoke (5), the ring magnet (6) and the stator core (14) are aligned in a longitudinal direction along the shaft (1) and are made approximately coincidental with each other.

Abstract: A brush-less motor includes a rotor with a magnet alternately magnetized N pole and S pole in a rotating direction, and a core with plural salient poles on which coils are wound. The core faces the magnet to form a magnetic circuit. Each one of the salient poles are toothed and provided with small teeth at an edge facing the magnet. The small teeth have a pitch corresponding to two poles of the magnet. Powering to the coil responsive to a rotor position drives the rotor. This structure substantially increases volumetric efficiency of the motor.

Abstract: A conductive attenuation body is arranged close to at least a part of surface of a material to be magnetized which has far lower conductivity than that of the attenuation body. Furthermore, the change in magnetic flux during magnetization is rapidly intensified for a sufficiently short period of time and rapidly weakened. The magnetization flux is impressed in form of penetrating the attenuation body. With the rapid change in the magnetization flux over time, in the conductive attenuation body, an eddy current is generated in a direction canceling the magnetization flux and thus the magnetization field weakens. The magnetization waveform can be adjusted by adjusting a thickness, an arrangement shape or expanse of the attenuation body.

Abstract: In a synchronous reluctance motor having a rotor having a plurality of pairs of an outer side slot formed at an outer periphery side and an inner side slot formed at inner side of the rotor. The distance between the outer periphery of the rotor and the outer side slot is determined to be the width of the stator magnetic pole portion of the stator multiplied by 0.7 to 1.3. A first total magnetic flux amount of an outer side permanent magnet disposed in the outer side slot is determined to be larger than or equal to a second total magnetic flux amount of an inner side permanent magnet disposed in the inner side slot.

Abstract: A method of determining magnet pole geometry for controlling cogging in an electric motor includes defining the magnet pole geometry in terms of at least one design parameter, predicting cogging as a function of the design parameter, and from the predicted cogging, selecting a value for the design parameter which corresponds to a desired level of cogging in the electric motor.

Abstract: The present invention is a motor of rotor with built-in permanent magnet, which includes an annular stator and a rotor. The annular stator has a cylindrical interior into which the rotor is inserted. A space is formed between a circumference surface of cylindrical interior and rotor. The rotor further includes a rotor core, and a plurality of openings are formed surrounding the rotor core. Each opening is with two parallel surfaces, a top surface and a bottom surface, and each of them is a flat plate figure. A suitable distance is between two side surfaces and an outer circumference of the rotor, and the two side surfaces of adjacent openings are spaced by a channel fo suitable width. A plurality of permanent magnets are arranged in openings by way of interlaced magnetic poles, and the shape of permanent matches the shape of the opening.

Abstract: A brushless DC motor including a stator having plural slots; and a rotor which has plural permanent magnets and is divided into three rotor blocks in a rotation axis direction, the three rotor blocks being layered so that the arrangement angles of the rotor blocks differ from each other by an amount of a mechanical angle in a rotary direction that is equivalent to one third of a pulsation period of cogging torque generated by the rotor and stator. A brushless DC motor including a rotor having plural magnetic poles provided at an equal pitch in a circumferential direction by mounting permanent magnets in magnet mounting holes; and a stator having plural slots arranged at an equal pitch in a circumferential direction.

Abstract: A permanent magnet motor for driving a fan is rotated while a movement of the rotor in a direction of thrust of a rotary shaft with a rotation of the fan is prevented by magnetic attraction force of a permanent magnet and a stator core. A surface magnetic flux density of the permanent magnet facing the stator core is lower at an end portion than at a central portion of the permanent magnet in the direction of thrust of the rotary shaft.

Abstract: A mover assembly of a reciprocating motor includes: a mover body disposed at a gap between an inner stator and an outer stator; permanent magnets fixed at an outer circumferential surface of the mover body and reciprocally moved together with the mover body in a direction of an induction magnetic field between the inner stator and the outer stator; and a mixed member made of a fiber and a resin to cover and fix the permanent magnets. The permanent magnets are arranged at an outer circumferential face of the mover body, covered with the mixed member obtained by mixing a fiber and a resin, and hardened to be fixed. Therefore, the permanent magnets can be firmly and easily fixed at the mover body. In addition, by molding the mover body with a non magnetic and non-conductive material, leakage of the magnetic force of the permanent magnets can be prevented.

Abstract: A brushless motor 1 comprises a rotor 3 having a magnet 2 and a stator 4 having a stator core 8. The stator core 8 has teeth 11 provided at the front ends thereof with auxiliary grooves to realize a pseudo-multi-slot arrangement. The magnet 2 has an axial length of LM while the stator core 8 has an axial length of LS, LS being greater than LM (LS>LM). The stator core 8 is provided at the opposite ends thereof with respective overhanging portions 15 that are not vis-à-vis the magnet 2. As a result, the magnetic flux is prevented from flowing into the stator core 8 through the axial end faces 8a thereof. In other words, the magnetic flux mostly flows into the stator core 8 through the front ends of the teeth. As a result, the pseudo-multi-slot effect produced by the auxiliary grooves is efficiently boosted to reduce cogging and other problems.

Abstract: A rotary electric machine including a flux-concentrating rotor with permanent magnets disposed between pole pieces, and a stator with teeth having a free end deprived of pole swellings and a concentrated winding. The pole pieces and the magnets are configured so as to minimize the difference Ld?Lq where Ld is inductance on a forward axis and Lq is inductance on a quadrature axis.

Abstract: A stepping motor includes a stator whose outer diameter is 8 mm or less and a rotor having a magnet disposed opposing to the stator. The stator has a core with pole teeth formed therein. The ratio between the thickness of the pole teeth formed in the core in the radial direction on the stator side and an outer diameter of the magnet on the rotor side, in other words, the quotient derived by dividing the thickness of the pole teeth by the outer diameter of the magnet, is set in a range between 0.121 and 0.148 to achieve good torque characteristic and linearity.

Abstract: A permanent magnet motor to reduce torque ripple includes a rotor having at least three segments. Each of the three segments is formed sequentially adjacent and aligned along an axis of the rotor. Each segment has at least one pair of permanent magnets disposed at a substantially equal interval in a peripheral direction of the rotor. First and second segments are skewed relative to each other by a first angular displacement, and the first and third segments are skewed relative to each other by a second angular displacement. The first and second angular displacements are selected to cause a net sum of torque ripple produced by each of the segments to be substantially equal to zero during an operation of the motor.

Abstract: A magnet fixing method of a linear servo motor wherein a cage for simultaneously securing positions and angles of a plurality of magnets is injection-molded where the cage is utilized to fix the magnets such that productivity is improved to shorten the working hours and reduce the manufacturing cost. A mutual twisting phenomenon can be prevented by interacting magnetic force among the plurality of magnets to thereby reduce the rate of defects.

Abstract: A motor is provided, which produces a high level of torque, displays minimal distortion of the induced voltage waveform, and is capable of being optimized in accordance with the required levels of controllability and cogging torque. The motor comprises a stator, in which windings are wound around each of a plurality of stator teeth provided on a stator core, and a rotor, in which a plurality of permanent magnets that exceeds the number of stator teeth are disposed at equal intervals around a periphery of a rotor core. In this motor, the stator teeth are arranged into a plurality of stator teeth groups, in which the windings to which the same phase voltage is applied are positioned adjacent to one another, and the windings on adjacent stator teeth in the group are wound in opposite directions.

Abstract: A capstan motor for a magnetic recording and reproducing apparatus includes a stator having a coil disposed on outer peripheral direction thereof, and a rotor having a magnet to correspond to coil and rotated by an electromagnetic interaction between the coil and the magnet. A capstan shaft is rotated integrally with the rotor, is fixed on the rotor and installed so that one side of the capstan shaft is cohered with a pinch roller taking a tape therebetween to drive the tape with the pinch roller. The magnet has a predetermined shape and is provided to apply magnetic force of the magnet eccentrically for an electromagnetic force generated on the coil so that a predetermined thrust can be applied to the capstan shaft toward one direction between upper and lower directions of the shaft direction.

Abstract: A permanent magnet rotating electric machine uses no skewing under a predetermined current and voltage condition to prevent torque from decreasing and to decrease pulsation torque to make the machine less vibrating and less noisy. The permanent magnet rotating electric machine includes a stator with multi-phase stator windings and a rotor with a plurality of permanent magnets internally embedded in a rotor core. The core shape of the rotor is uniform in the depth (longitudinal) direction with no skewing in the arrangement of the permanent magnets. The permanent magnets are symmetrical with respect to the rotation direction, but irregular with respect to the depth direction, for each pole. A magnetic flux generated from the between-pole permanent magnets almost equals a magnetic flux generated from the pole-center permanent magnet.

Abstract: A rotor for a synchronous motor capable of increasing output torque and reduce inductance. An outer periphery of each pole of the rotor in a cross section perpendicular to an axis of the rotor is defined on the basis of a curve of a hyperbolic function. Since an outer periphery of one pole of the rotor at a central apex portion is substantially identical with that of a conventional rotor defined by a circular arc, the output torque of the synchronous motor using this rotor is not decreased. At side portions adjacent to the central apex portion, the outer periphery is positioned inner, i.e., closer to the axis of the rotor than the outer periphery defined by the circular arc, so that a gap between the outer periphery of the rotor and an inner periphery of a stator is made greater to reduce the inductance of the synchronous motor.

Abstract: An inner rotor motor includes a rotor which has a plurality of circumferentially arranged magnetic poles and a stator which is positioned outside a circumference of the rotor and has a stator core which includes a plurality of magnetic pole teeth which face the rotor in an opposed manner and arranges coils for respective magnetic pole teeth. In such a constitution, the stator is arranged within a center angle of 180° with respect to a center of rotation of the rotor. Further, pitches of the magnetic pole teeth in the rotor circumferential direction along which respective rotor facing surfaces of the magnetic pole teeth are arranged are set smaller than pitches of the rotor in the rotor circumferential direction along which the magnetic poles of the rotor are arranged.

Abstract: A brush motor has a magnetic sensor provided for detecting a change in a field magnet occurring in correspondence with a change in a rotational position of a rotor core.

Abstract: A rotary electrical machine device that reduces the distortion generated in the waveform of the electromotive force as much as possible while adopting inexpensive processes and assembling methods.

Abstract: In order to provide a motor characterized by a high level of efficiency equal to or better than that of using the silicon steel plate, achieved by easy production method and reduced core loss, which result from reduction in the manpower for production by using the sintered metal or powdered iron core in at least one of the stator and rotor, the present invention provides a motor comprising a stator and a rotor wherein either one of said stator or rotor has a magnet, and the other has a magnetic substance. This motor is further characterized in that the main magnetic flux flowing between the stator and rotor changes in the three-dimensional directions according to the magnetic structure of this motor, and at least part of said magnetic substance is composed of an aggregate of magnetic powder.

Abstract: To provide a permanent-magnet motor having a permanent magnet which can reduce the vibration and the noise without lowering the efficiency of the motor, the permanent-magnet motor according to, the present invention has a stator 1 having stator winding of plural phases, a rotor 10 having a stator core 12 facing to inside of the stator across a gap part and a permanent magnet 14 provided to the rotor core. In the permanent-magnet motor, the permanent magnet 14 is made to have both a convex part to the inner diameter side and a convex part to the outer diameter side in the cross section taken vertically to the rotation axis, and a focus of magnetic orientation of each magnetic pole of the permanent magnet is located outside of the rotor 10.

Abstract: A stator of the stepping motor of the invention includes an annular shaped yoke portion, a stator iron-core having twelve stator main poles each having a plurality of small teeth on the tip end thereof and stator coils wound in the stator iron-core as three-phase winding. The stator rotatably supports a hybrid type rotor having a cylindrical permanent magnet that is sandwiched between a pair of rotors each having pole teeth around the circumferential surface to be opposite to the small teeth. Second, third, fourth and fifth harmonic components are removed by composing cogging torque of the respective phases by means of the three-phase twelve-pole construction. Any one harmonic component of the cogging torque among the second to fifth harmonic components is independently erased by making a difference between the small teeth pitch and the rotor teeth pitch, thereby the selected harmonic component is doubly erased.

Abstract: A permanent magnet electric machine with reduced cogging torque includes a plurality of axial rotor sections that are defined on a radially outer surface of a rotor. The axial rotor sections include a set of permanent magnets that are in an unmagnetized state and that have opposite edges that are aligned with an axis of the rotor. The axial rotor sections are rotationally offset such that the edges of the permanent magnets create stair step interfaces. The n sets of permanent magnets are magnetized using a magnetizing fixture. The permanent magnets have a generally rectangular shape and are preferably arc magnets or breadloaf magnets. The conductors of the magnetizing fixture are aligned with the stair step interfaces. A magnetic field induced in the permanent magnets is substantially reduced along the stair step interfaces.