Claw-pole dynamo with radially offset yoke arms

A claw-pole generator comprising:

• a permanent magnet unit extending in a circumferential direction;
• a coil disposed radially inwardly of the permanent magnet unit;
• a yoke surrounding the coil, wherein the permanent magnet unit rotates relative to the yoke around an axis, wherein the yoke comprises:
• a plurality of laminated first yoke arms disposed on a first axial side of the coil, each first yoke arm having a first yoke arm radially outer portion and a first yoke arm radially inner portion, and each first yoke arm comprising a plurality of laminated first plate-shaped pieces;
• a plurality of laminated second yoke arms disposed on a second axial side of the coil, each second yoke arm having a second yoke arm radially outer portion and a second yoke arm radially inner portion, and each second yoke arm comprising a plurality of laminated second plate-shaped pieces;
• wherein each first yoke arm radially inner portion faces a corresponding second yoke arm radially inner portion in the axial direction;
• wherein the plurality of first yoke arm radially outer portions extend axially toward the second axial side of the coil;
• wherein the plurality of second yoke arm radially outer portions extend axially toward the first axial side of the coil;
• wherein the plurality of first yoke arm radially outer portions are interleaved with the plurality of second yoke arm radially outer portions in a circumferential direction;
• and
• a bobbin that has a tubular member that extends in the axial direction and first and second flanges that are disposed at opposite axial ends of the tubular member, wherein the coil is wound around the outer circumference of the tubular member.

A claw-pole generator comprising:

• a permanent magnet unit extending in a circumferential direction;
• a coil disposed radially inwardly of the permanent magnet unit;
• a yoke surrounding the coil, wherein the permanent magnet unit rotates relative to the yoke around an axis, wherein the yoke comprises:
• a plurality of first yoke arms disposed on a first axial side of the coil, each first yoke arm having a first yoke arm radially outer portion and a first yoke arm radially inner portion, and each first yoke arm comprising a plurality of first plate-shaped pieces;
• a plurality of second yoke arms disposed on a second axial side of the coil, each second yoke arm having a second yoke arm radially outer portion and a second yoke arm radially inner portion, and each second yoke arm comprising a plurality of second plate-shaped pieces;
• wherein each of the plurality of first yoke arms and the plurality of second yoke arms are circumferentially separate;
• wherein each first plate-shaped piece comprises:
• a first radially outer portion that extends from the first axial side toward the second axial side and is disposed between the permanent magnet unit and the coil;
• and
• a first radially inner portion that is magnetically coupled to the first radially outer portion, wherein the first radially inner portion is disposed at the first axial side of the coil;
• wherein each second plate-shaped piece comprises:
• a second radially outer portion that extends from the second axial side toward the first axial side and is disposed between the permanent magnet unit and the coil;
• and
• a second radially inner portion that is magnetically coupled to the second radially outer portion, wherein the second radially inner portion is disposed at the second axial side of the coil;
• wherein each first yoke arm radially inner portion faces a corresponding second yoke arm radially inner portion in an axial direction, and wherein the plurality of first yoke arm radially outer portions are interleaved with the plurality of second yoke arm radially outer portions.

A claw-pole generator comprising:

• a permanent magnet unit extending in a circumferential direction;
• a coil disposed radially inwardly of the permanent magnet unit;
• a yoke surrounding the coil, wherein the permanent magnet unit rotates relative to the yoke around an axis, wherein the yoke comprises:
• a plurality of first yoke arms disposed on a first axial side of the coil, each first yoke arm having a first yoke arm radially outer portion and a first yoke arm radially inner portion, and each first yoke arm comprising a plurality of first plate-shaped pieces;
• a plurality of second yoke arms disposed on a second axial side of the coil, each second yoke arm having a second yoke arm radially outer portion and a second yoke arm radially inner portion, and each second yoke arm comprising a plurality of second plate-shaped pieces;
• wherein each first plate-shaped piece comprises:
• a first radially outer portion that extends from the first axial side toward the second axial side and is disposed between the permanent magnet unit and the coil;
• and
• a first radially inner portion that is magnetically coupled to the first radially outer portion, wherein the first radially inner portion is disposed at the first axial side of the coil;
• wherein each second plate-shaped piece comprises:
• a second radially outer portion that extends from the second axial side toward the first axial side and is disposed between the permanent magnet unit and the coil;
• and
• a second radially inner portion that is magnetically coupled to the second radially outer portion, wherein the second radially inner portion is disposed at the second axial side of the coil;
• wherein each first yoke arm radially inner portion faces a corresponding second yoke arm radially inner portion in an axial direction, and wherein the plurality of first yoke arm radially outer portions are interleaved with the plurality of second yoke arm radially outer portions;
• a first flange disposed at the first axial side of the coil, wherein the first flange has a plurality of first radially inner groove portions and a plurality of first radially outer groove portions, wherein each first radially inner groove portion is associated with at least one of the plurality of first radially outer groove portions, wherein the plurality of first radially inner groove portions and the plurality of first radially outer groove portions are disposed circumferentially around the first flange, wherein each of the plurality of first radially inner groove portions receives therein the first radially inner portion of at least one of the plurality of first plate-shaped pieces of a corresponding one of the plurality of first yoke arms, and wherein each of the plurality of first radially outer groove portions receives therein a proximal portion of the first radially outer portion of at least one of the plurality of first plate-shaped pieces of a corresponding one of the plurality of first yoke arms;
• and
• a second flange disposed at the second axial side of the coil, wherein the second flange has a plurality of second radially inner groove portions and a plurality of second radially outer groove portions, wherein each second radially inner groove portion is associated with at least one of the plurality of second radially outer groove portions, wherein the plurality of second radially inner groove portions and the plurality of second radially outer groove portions are disposed circumferentially around the second flange, wherein each of the plurality of second radially inner groove portions receives therein the second radially inner portion of at least one of the plurality of second plate-shaped pieces of a corresponding one of the plurality of second yoke arms, and wherein each of the plurality of second radially outer groove portions receives therein a proximal portion of the second radially outer portion of at least one of the plurality of second plate-shaped pieces of a corresponding one of the plurality of second yoke arms therein.

A bicycle hub dynamo that is disposed in the center of a bicycle wheel, wherein the dynamo comprises:

• a hub shaft for mounting to a frame of the bicycle;
• a casing having a cylindrical case main unit that extends along an axis of the hub shaft and a pair of hub flanges disposed at opposite ends of the case main unit;
• a pair of bearings that rotatably support the case main unit on the hub shaft;
• an annular permanent magnet disposed on an inner circumferential surface of the case main unit;
• an interior fixed unit disposed radially inwardly of the permanent magnet and fixed relative to the hub shaft;
• an annular coil disposed radially inwardly of the permanent magnet and wrapped around the interior fixed unit;
• a yoke surrounding the coil, wherein the permanent magnet unit rotates relative to the yoke around an axis, wherein the yoke comprises:
• a plurality of circumferentially laminated first yoke arms disposed on a first axial side of the coil, wherein each first yoke arm has a first yoke arm radially outer portion, a first yoke arm radially inner portion, and a first yoke arm linking portion connecting the first yoke arm radially outer portion and the first yoke arm radially inner portion, and wherein each first yoke arm comprises a plurality of laminated first plate-shaped pieces;
• a plurality of circumferentially laminated second yoke arms disposed on a second axial side of the coil, wherein each second yoke arm has a second yoke arm radially outer portion, a second yoke arm radially inner portion, and a second yoke arm linking portion connecting the second yoke arm radially outer portion and the second yoke arm radially inner portion, and wherein each second yoke arm comprises a plurality of laminated second plate-shaped pieces;
• wherein each first plate-shaped piece comprises:
• a first radially outer portion that extends from the first axial side toward the second axial side and is disposed between the permanent magnet unit and the coil;
• and
• a first radially inner portion that is connected to the first radially outer portion through a first linking portion, wherein the first radially inner portion is disposed at the first axial side of the coil;
• wherein each second plate-shaped piece comprises:
• a second radially outer portion that extends from the second axial side toward the first axial side and is disposed between the permanent magnet unit and the coil;
• and
• a second radially inner portion that is connected to the second radially outer portion through a second linking portion, wherein the second radially inner portion is disposed at the second axial side of the coil;
• wherein each first yoke arm radially inner portion faces a corresponding second yoke arm radially inner portion in an axial direction, and wherein the plurality of first yoke arm radially outer portions are interleaved with the plurality of second yoke arm radially outer portions in a circumferential direction.