Devices and methods for magnetic flux return optimization in electromagnetic machines

An apparatus, comprising:

• a rotor element configured to be disposed for movement relative to a stator, the rotor element including:
• a backing member formed at least in part of a ferromagnetic material and having a first surface and a second surface opposite the first surface,
• a first magnetic pole having a first polarity coupled to the backing member on the first surface, and
• a second magnetic pole having a second polarity opposite the first polarity coupled to the backing member on the first surface,
• the backing member having a length, a width and a thickness, the second magnetic pole being disposed relative to the first magnetic pole at a distance defined in a direction of the width of the backing member,
• the thickness of the backing member varying along the width of the backing member such that the backing member includes a plurality of alternating first portions and second portions, the first portions including protrusions extending from the second surface and being thicker than the second portions,
• the rotor element being disposed for linear movement relative to the stator, the direction of the linear movement being approximately parallel to a direction of the width.

An apparatus comprising:

• a rotor element configured to be disposed for movement relative to a stator, the rotor element including:
• a backing member formed at least in part of a ferromagnetic material, the backing member having a first surface and a second surface opposite the first surface,
• a first magnetic pole having a first polarity coupled to the backing member, and
• a second magnetic pole having a second polarity opposite the first polarity and coupled to the backing member,
• the backing member having a length defined radially from an innermost edge of the backing member to an outermost edge of the backing member, a width defined in a circumferential direction around the backing member and a thickness defined between the first surface and the second surface of the backing member, the second magnetic pole being disposed relative to the first magnetic pole at a distance defined in a direction of the width of the backing member, the length of the backing member varying along the width of the backing member.

An apparatus, comprising:

• a rotor element configured to be disposed for movement relative to a stator, the rotor element including:
• a backing member formed at least in part of a ferromagnetic material,
• a first magnetic pole having a first polarity coupled to the backing member, and
• a second magnetic pole having a second polarity opposite the first polarity and coupled to the backing member,
• the backing member having a length, a width and a thickness, the second magnetic pole being disposed relative to the first magnetic pole at a distance defined in the direction of the width of the backing member, the length of the backing member varying along the width of the backing member,
• the rotor element being disposed for linear movement relative to the stator, the direction of the linear movement being approximately parallel to a direction of the width.