31results about How to "Reduce the cogging torque" patented technology

The present invention relates to a rotor assembly for an electrical machine, comprising: a rotor body of generally cylindrical shape having a substantially cylindrical surface configured for facing an air-gap between the rotor assembly and a stator of the electrical machine, and permanent magnets embedded in said rotor body, wherein grooves are formed in said air-gap facing surface for manipulating the distribution of magnetic flux created by said permanent magnets.

A magnetic circuit component having a plurality of claws arranged in a plurality of rows, with the base of each claw connected to a common yoke. A plurality of non-interlaced coils constituting a multi-phase winding are included, with the coils being wound around the bases of corresponding claws, and being distributed uniformly in the direction of motion.

Although in a conventional permanent magnet type synchronous motor, cogging torque is reduced by displacing permanent magnets of a rotor in a circumferential direction or displacing a stator core in a circumferential direction, since the skew so produced reduces the output of the motor and moreover the winding work of windings cannot be automated to make the resulting motor highly expensive, split cores are provided which solves those problems and enables the winding work of windings to be automated so as to obtain an inexpensive and high-output motor.There are provided a plurality of split cores (100) made up of laminated iron cores each having formed thereon a tooth (6), and a yoke (5) and a pole piece (9) which are made to connect to the tooth (6) at both ends thereof, and arranged and connected together into an annular shape to make up a stator, characterized in that both ends of the yokes (5) and both ends of the pole pieces (9) are displaced in one circumferential direction by laminated iron core from a top laminated layer to a bottom laminated layer of the iron cores of the split cores.

To reduce the cogging torque of servomotors, electric power steering motors, and others, there is provided a permanent magnet motor comprising: a rotor 10 comprising a rotor yoke 11 and a plurality of permanent magnets (M1-M10); and a stator 20 comprising a stator yoke 22, salient magnetic poles 21, and armature windings 23, wherein at least one of the permanent magnets is disposed in an adjustment position that is displaced from a corresponding reference position in at least one of the circumferential, radial, and axial directions of the rotor yoke, and the plurality of permanent magnets excluding the permanent magnet disposed in the adjustment position is disposed in the reference positions, and wherein the adjustment position is set so that the permanent magnet motor in which at least one of the plurality of permanent magnets is disposed in the adjustment position has a smaller cogging torque than a permanent magnet motor in which all of the plurality of permanent magnets are disposed in the reference positions; and a method for adjusting a cogging torque of a permanent magnet motor.

A permanent magnet motor is provided. The permanent magnet motor includes a stator having a stator shaft having an outer surface, K salient teeth formed upon the outer surface, and K winding slots formed among the K salient teeth, and a rotor having a first inner surface facing the outer surface, and P pairs of permanent magnets formed on the first inner surface, each of which has a second inner surface facing the outer surface and at least a groove formed on the second inner surface to reduce a cogging torque.

There is provided an interior permanent magnet rotary motor that can reduce cogging torque and can also reduce the amount of permanent magnet used, without reducing torque. In an interior permanent magnet rotary motor of the present invention having N slots 6 and P permanent magnet magnetic pole sections 11, in which P / N is set in the range of ⅔ to 43 / 45 and Po in a irreducible fraction Po / No of the P / N is set to be an odd number, an pole arc ratio ψp is defined to be the ratio of θpp / θp where an angle between two line segments assumed for a pair of flux barriers 21, each of which connects the center of a rotor core and one of a plurality of corners of the section of each flux barrier that is closest to the surface of the rotor core 9 is indicated by the θpp and an angle obtained by dividing the full circumference angle (360°) of the rotor core by the number of the permanent magnet pole sections is indicated by the θp. Then, the pole arc ratio indicated by Ψp is determined is so as to satisfy the relation of Ψp=2mP / N+P / 4LCM (P, N)−2n, in which LCM (P, N) is the least common multiple between P and N, m and n are arbitrary natural numbers, and the Ψp is larger than zero but smaller than one.

Rotor assembly for an electrical machine, wherein a body of generally cylindrical shape having an inner opening for coaxially mounting the body on a shaft, permanent magnets embedded in said body, wherein at least one of the permanent magnets is split in at least two magnet sections which extend from about the inner opening towards the outer periphery of the body and are inclined towards a plane, which extends in a radial direction of the body.

A motor capable of reducing cogging torque depending on teeth of a stator, and a motor manufacturing apparatus for manufacturing this motor. The angles of rolling directions of cores stacked are set so that the phase difference between the phases of cogging torques produced on the cores is 180° so that the cogging torques produced on the cores cancel each other to reduce the total cogging torque in the motor. The motor comprises a laminated core formed by stacking a plurality of cores made from a rolled electromagnetic sheet steel. The cores forming the laminated core have rolling directions different from each other by a specified machine angle determined depending on the number of slots and / or the number of poles, where the specified machine angle is an angle which produces a phase difference of 180° between the phases of cogging torques produced due to magnetic anisotropy of the cores and the arrangement of teeth depending on the number of slots and / or poles of the motor.

Flat rolled magnetic steel sheets and strip or a die is turned in the press forming process. Rotor cores are stacked with turning through an angle which is an odd number multiple of about (360° / (number of slots in the motor×natural number n×2)) and stator cores are stacked with turning through an angle which is an odd number multiple of (360° / (number of poles in the motor×natural number n×2)). Stacking with turning through an angle which is an odd number multiple converts the phases of cogging torques into mutually opposite phases and cancels and reduces the cogging torque caused by magnetic anisotropy.

Split cores comprising laminated iron cores each having formed thereon a tooth, and a yoke and a pole piece which are connected to the tooth at both ends thereof, and arranged and connected together into an annular shape to make a stator. Both ends of the yokes and both ends of the pole pieces are displaced in one circumferential direction by laminated iron core from a top laminated layer of the iron cores of the split cores to a bottom laminated layer of the iron cores or split cores.

In a brushless motor includes a rotor having 2n magnetic poles and a stator having 3n slots, the magnetic poles of the rotor are composed of segment magnets arranged in three columns extending in an axial direction. The magnets of each column are displaced from the magnet of either adjacent column in a circumferential direction, forming a 3-stage step-skew structure. The segment magnets have a skew angle θskew ranging from 36° to 57° in terms of electrical angle.

An interior permanent magnet rotary motor of the present invention has N slots and P permanent magnet magnetic pole sections, (2 / 3<=P / N<= 43 / 45). Po is an irreducible fraction Po / No of the P / N is an odd number, and a pole arc ratio psip equals thetapp / thetap. thetapp is an angle between two line segments assumed for a pair of flux barriers, each of which connects the center of a rotor core and one of corners of the section of each flux barrier that is closest to the surface of the rotor core. thetap is an angle obtained by dividing 360° by the number of the permanent magnet pole sections. The pole arc ratio indicated by Psip (0<4n<1) is determined by the expression of Psip=2mP / N+P / 4LCM (P, N)-2n, where LCM (P, N) is the least common multiple between P and N, m and n are arbitrary natural numbers.

Rotor assembly for an electrical machine, including a body of generally cylindrical shape having an inner opening, wherein slots are provided in the body, the slots extending from the inner opening towards the outer periphery of the body; permanent magnets disposed in said slots; wherein at least one of the slots comprises an end section near the outer periphery of the body having an area of enlarged width.

A drive apparatus for an electric bike includes a hollow housing body, an internal ring gear fixed to the housing body, and a main shaft. At least two motor units are mounted in the housing body. Each motor unit includes a support bracket and a number of motors mounted on the support bracket. Each motor drives the internal gear through a transmission mechanism to rotate the housing body about the main shaft. The motors share one controller. Peaks of the motor cogging torque can be staggered.

To reduce the cogging torque of servomotors, electric power steering motors, and others, there is provided a permanent magnet motor comprising: a rotor 10 comprising a rotor yoke 11 and a plurality of permanent magnets (M1-M10); and a stator 20 comprising a stator yoke 22, salient magnetic poles 21, and armature windings 23, wherein at least one of the permanent magnets is disposed in an adjustment position that is displaced from a corresponding reference position in at least one of the circumferential, radial, and axial directions of the rotor yoke, and the plurality of permanent magnets excluding the permanent magnet disposed in the adjustment position is disposed in the reference positions, and wherein the adjustment position is set so that the permanent magnet motor in which at least one of the plurality of permanent magnets is disposed in the adjustment position has a smaller cogging torque than a permanent magnet motor in which all of the plurality of permanent magnets are disposed in the reference positions; and a method for adjusting a cogging torque of a permanent magnet motor.

A single-phase outer-rotor motor and a stator thereof are provided. The stator includes a stator core having a yoke and a number of teeth. Each tooth includes a tooth body and a toot tip. A winding slot is formed between each two adjacent tooth bodies. A slot opening is formed between each two adjacent tooth tips. The tooth tip protrudes beyond the tooth body. Inner surfaces of at least part of the tooth tips facing the stator are formed with cutting grooves such that a portion of the tooth tip outside the cutting groove is capable of being tilted outwardly to enlarge the slot opening and deformed inwardly to narrow the slot opening.

The present disclosure may reduce cogging torque by stacking steel plates which can form a stage skew by stacking the steel plates without reversing the front and back sides or by forming the stage skew by stacking the steel plates capable of easily distinguishing the front and back sides, and reduce both the sixth-order and twelfth-order dq coordinates of harmonic components, thereby achieving low toque ripple, high efficiency, and improved controllability. To this end, the present disclosure is an internal permanent magnet motor having a rotor in which a predetermined skew angle θs is formed between adjacent stages along the axial direction, wherein the rotor is formed by stacking a plurality of the steel plates having the same shape, each of the steel plates has a group of fastening holes made of the same number of the fastening holes as the number of the stages, and each of the fastening holes constituting the fastening group is formed at a position where the skew angle θs changes along a circumferential direction one by one.

A single-phase outer-rotor motor and a stator thereof are provided. The stator includes a stator core having a yoke and a number of teeth. Each tooth includes a tooth body and a tooth tip. A winding slot is formed between each two adjacent tooth bodies. A slot opening is formed between each two adjacent tooth tips. The tooth tip protrudes beyond the tooth body. Inner surfaces of at least part of the tooth tips facing the stator are formed with cutting grooves such that a portion of the tooth tip outside the cutting groove is capable of being tilted outwardly to enlarge the slot opening and deformed inwardly to narrow the slot opening.

A rotor for an electric power steering motor is configured to include a rotor core having a step skew structure constituted of two independent cores as well as to use shrink fitting to fasten the two cores to a shaft. It may also be configured such that a magnetic center of the rotor core is adjusted by controlling a dimension thereof from a tip of the shaft and by shrink fitting the two cores.

A rotor includes a rotor core in which laminate steel plates extending in a radial direction with respect to a central axis are laminated in an axial direction, and magnets are inserted into the rotor core. Each of the laminate steel plates includes a base portion positioned on a radially outer side of the central axis, and pieces separately disposed on a radially outer side of the base portion with penetrating portions therebetween, and arranged side by side at predetermined intervals in a circumferential direction. The magnets are inserted into the penetrating portions and arranged side by side at predetermined intervals in the circumferential direction. Space portions are provided between the magnets adjacent to each other in the circumferential direction. A circumferential length of the pieces is shorter than a circumferential length of the magnets.

The present disclosure may reduce cogging torque by stacking steel plates which can form a stage skew by stacking the steel plates without reversing the front and back sides or by forming the stage skew by stacking the steel plates capable of easily distinguishing the front and back sides, and reduce both the sixth-order and twelfth-order dq coordinates of harmonic components, thereby achieving low toque ripple, high efficiency, and improved controllability. To this end, the present disclosure is an internal permanent magnet motor having a rotor in which a predetermined skew angle θs is formed between adjacent stages along the axial direction, wherein the rotor is formed by stacking a plurality of the steel plates having the same shape, each of the steel plates has a group of fastening holes made of the same number of the fastening holes as the number of the stages, and each of the fastening holes constituting the fastening group is formed at a position where the skew angle θs changes along a circumferential direction one by one.