An electric rotating machine including a rotor-stator device having a permanent magnet symmetrical rotor and a stator structure. The stator is in capsule form and has a pair of pole pieces and a magnetic flux transmitting structure for transmitting flux to the pair of pole pieces. The flux transmitting structure includes a pair of support members between which the rotor and stator structure are supported. The rotor is journaled for rotation in the support members. A rotatable gear assembly is supported on at least one of the support members and spaced from the rotor and stator structure to provide selective speeds in response to the rotation of the rotor. In one described embodiment the magnetic flux transmitting structure may comprise a generally U-shaped structure.

Electric rotating machine

A linear stepper motor is provided with a feature to cause it to return to a zero position when current is cut off. The motor is formed of a stator armature assembly and a permanent magnet rotor assembly with poles thereof facing poles of the stator armature. The rotor assembly includes a rotor core formed as a nut with an axial threaded aperture extending therethrough. A shaft assembly includes a shaft screw mating with the rotor core nut, a front shaft affixed thereto, and a fixed sleeve overfitting the front shaft to permit axial motion thereof. A ball-and-groove arrangement in the front shaft and the sleeve prevents rotation of the shaft without impairing axial movement thereof. A spring causes return of the shaft to zero when there is no current applied to the stator armature. The spring can, for example, be a coil compression spring overfitting a portion of the shaft or a spiral torsion spring extending between the rotor and the stator armature.

Return-to-zero stepper motor

An axial gap motor may benefit from a reduction of axial force on the rotor, which may reduce load on the rotor and bearings and reduce the vibration on the surface of the rotor. An air gap is positioned on the stator facing the rotor, and an auxiliary yoke is positioned facing the air gap on the other side of the rotor. Magnetic flux circulates from the rotor and the axial force α is applied to the rotor when the magnetic flux passes by the air gap surface on the stator side of the rotor. Axial force β is applied to the rotor when the magnetic flux passes by the air gap surface on the auxiliary yoke side of the rotor. Axial force β is opposite, or reverse, of axial force α and reduces axial force α so axial force α reduces the load on the rotor and bearings.

Axial gap motor

The invention relates to a transversal flux machine having a stator (13) and an external rotor (16) disposed about the stator (13), the stator (13) comprising two axial end faces (273, 276), having an inner core (107) of the stator (13), having a cooling path disposed radially within the inner core (107), characterized in that a cooling path either a) protrudes out of the transversal flux machine (10)on the axial end face (273) of the stator (13), wherein said transversal flux machine faces away from an inlet side (303), or b) the cooling path protrudes out of the transversal flux machine (10) on the axial end face (273) of the stator (13), wherein said transversal flux machine faces away from the inlet side, and wherein the cooling path runs between the inlet and the outlet in an intermediate space (265) between the stator (13) and the external rotor (16). of the stator (13) facing the inlet side, wherein the cooling path between the inlet and the outlet runs in an intermediate space (265) between the stator (13) and the external rotor (16).

Transversal flux machine

A stator coil used in an electric motor, including a bobbin formed by insulating material and composed of a hollow cylindrical portion and two end plates provided projectingly toward the outside in the radial direction from the cylindrical portion at both ends in the axial direction thereof, at least two connector plates made of conductive material of which one end is inserted into an outer periphery of one end plate of the bobbin and of which the other end is extended outside in the radial direction of the end plate, and an exciting coil wound on the cylindrical portion. One terminal portion of a covered wire which constitutes the exciting coil is conductively connected to the one connector plate, and the other terminal portion is conductively connected to the other connector plate. The connector plates are insulatingly held in a housing of the electric motor and their free ends are provided projectingly outside the outer surface of the housing, thereby forming a connector.

Electric motor having a molded housing and connector plates projected thereon

A small permanent magnet synchronous motor having one or more pairs of stator sections mounted in tandem. Each stator section includes a first annular stator member of generally U-shaped cross section with multiple pole pieces around the inside of the annulus parallel to the axis, the pole pieces preferably being of tapered construction. A similar second annular stator member interfits with the first stator member; the pole pieces of the second stator member are interleaved one-for-one with the pole pieces of the first stator member. The stator members are formed of mild low-carbon steel that is annealed after fabrication. In each stator section, a coil encompasses the pole pieces of the stator members. The rotor is a permanent magnet ring with as many poles as the stator sections, mounted in a single-unitary bearing structure. The motor is assembled by coating one inner frame member with an epoxy resin adhesive, assembling the inner frame members back-to-back on a gauge hub with interengaging index elements assuring accurate alignment at a displacement of 90* electrically between the stator sections, then adding the coils and outer stator members.

Ivan W Maier

Papers

Permanent magnet motor