Electric motor rotor assembly having magnet retention feature
A rotor assembly includes a rotor core that defines a plurality of cavities and includes a plurality of laminations having annular bodies and stackably arranged to form the rotor core. The plurality of laminations includes a plurality of notch laminations and at least one tab lamination. Each notch lamination defines a plurality of first apertures. Each first aperture has a notch at a portion of the first aperture. The tab lamination defines a plurality of second apertures and includes flexible tabs extending toward the second apertures. The plurality of first apertures and the plurality of second apertures define at least a portion of the plurality of the cavities. A set of notch laminations are stacked with the tab lamination, where the notches of the set of notch laminations align with the flexible tabs of the tab lamination.
1 . A rotor assembly for an electric motor, comprising:
a rotor core defining a plurality of cavities and comprising a plurality of laminations, and
a plurality of magnets provided in the plurality of cavities wherein:
the plurality of laminations has annular bodies and includes:
a plurality of notch laminations each defining a plurality of first apertures, wherein each first aperture has a notch at a portion of the first aperture,
a plurality of tab laminations each defining a plurality of second apertures and including a plurality of flexible tabs extending towards the second apertures, and
a plurality of side tab laminations each defining a plurality of third apertures and including a pair of side tabs extending toward each third aperture, a first side tab being provided at a first lateral side of the third aperture and a second side tab being provided at a second lateral side of the third aperture opposite of the first lateral side, and the first side tab being closer to a center of the annular body than the second side tab, the plurality of first, second, and third apertures define at least a portion of the plurality of the cavities,
a set of the notch laminations are stacked with at least one tab lamination, wherein the notches align with a set of flexible tabs among the plurality of flexible tabs the set of flexible tabs bends toward the notches by the magnet,
at least one side tab lamination among the plurality of side tab laminations is arranged above the at least one tab lamination,
the magnet is laterally retained between the first side tab and the second side tab,
the plurality of flexible tabs includes a flexible side tab that vertically aligns with and is under the first side tab, and
the flexible side tab bends away from the first side tab by the magnet.
2 . The rotor assembly of claim 1 , wherein the plurality of laminations further includes a stopper lamination defining a plurality of fourth apertures, each fourth aperture has at least one tab extending into the fourth aperture, wherein the stopper lamination is provided as an end lamination of the rotor core and is adapted to retain the magnets in the cavities by the tabs.
3 . The rotor assembly of claim 1 , wherein:
a subset of stacked laminations includes one tab lamination and the set of the notch laminations, and
the subset of stacked laminations is arranged at a first end of the rotor core and a second tab lamination from among the plurality of tab laminations is provided as an end lamination at a second end of the rotor core opposite of the first end to abut with and retain the magnet.
4 . The rotor assembly of claim 1 , wherein:
a portion of the plurality of laminations form a plurality of subset of stacked laminations,
each subset of stacked laminations includes one tab lamination and the set of the notch laminations stacked with the one tab lamination, and
the flexible tabs of the plurality of subset of stacked laminations form an array of the flexible tabs along the cavities and are adapted to contact and bias the magnet toward an inner surface of the cavity.
5 . The rotor assembly of claim 1 , wherein:
the at least one tab lamination includes a second pair of side tabs at each secondary aperture,
the second pair of side tabs extend toward the second aperture,
a first side tab of the second pair of side tabs is provided at a first lateral side of the second aperture and a second side tab of the second pair of side tabs is provided at a second lateral side of the second aperture opposite of the first lateral side, and
the magnet is retained between the second pair of side tabs.
6 . The rotor assembly of claim 1 , wherein:
the plurality of magnets includes a first set and a second set of magnets, wherein the first set of magnets are smaller than the second set of magnets, and
the plurality of cavities includes a first set of cavities having the first set of magnets and a second set of cavities having the second set of magnets.
7 . The rotor assembly of claim 1 , wherein:
a portion of the plurality of laminations form a subset of stacked laminations,
each subset of stacked laminations includes one tab lamination from among the plurality of tab laminations and the set of the notch laminations stacked with the one tab lamination,
the rotor core includes a plurality of the subset of stacked laminations, and
the flexible tabs of the plurality of the subset of stacked laminations form an array of the flexible tabs along the cavities and are adapted to contact and bias the magnet toward an inner surface of the cavity.
8 . The rotor assembly of claim 1 , wherein the flexible tabs of the tab lamination includes a flexible center tab provided at a center portion of the second apertures.
9 . The rotor assembly of claim 8 , wherein:
each tab lamination includes the flexible side tab
a portion of the plurality of laminations form a subset of stacked laminations,
the subset of stacked laminations includes one tab lamination and the set of the notch laminations stacked with the one tab lamination,
the rotor core includes a plurality of the subset of stacked laminations, and
the flexible center tabs and the flexible side tabs of the plurality of the subset of stacked laminations form an array of the flexible center tabs and an array of the flexible side tabs along the cavities and are adapted to contact and bias the magnet toward an inner surface of the cavity.
10 . The rotor assembly of claim 1 , wherein:
each first aperture of the notch lamination among the plurality of notch laminations has a plurality of the notches, and
at least one second tab lamination among a plurality of tab laminations includes a plurality of the flexible tabs that align with the plurality of the notches.
11 . A rotor assembly for an electric motor, the rotor assembly comprising:
a rotor core defining a plurality of cavities and comprising a plurality of laminations; and
a plurality of magnets arranged in the plurality of cavities, wherein:
the plurality of laminations has annular bodies and includes:
a plurality of notch laminations each defining a plurality of first apertures, wherein each first aperture has a notch at a portion of the first aperture,
a plurality of tab laminations each defining a plurality of second apertures and including at least one flexible tab extending toward the second apertures, and
a plurality of side tab laminations each defining a plurality of third apertures and including a pair of side tabs extending toward the third aperture, a first side tab being provided at a first lateral side of the third aperture and a second side tab being provided at a second lateral side of the third aperture opposite of the first lateral side, and the first side tab being closer to a center of the annular body than the second side tab,
a portion of the plurality of laminations form a subset of stacked laminations,
the subset of stacked laminations includes one tab lamination and a set of notch laminations from among the plurality of notch laminations stacked with the one tab lamination,
the first apertures, the second apertures, and the third apertures align with each other to form a portion of the plurality of cavities,
at least one side tab lamination among the plurality of side tab laminations is arranged above the at least one tab lamination,
the magnet is laterally retained between the first side tabs and the second side tabs of the plurality of side tab laminations,
the at least one flexible tab includes a flexible center tab provided at a center portion of the second apertures and a flexible side tab vertically aligns with and is under the first side tab,
the flexible side tab bends away from the first side tab by the magnet, and
the flexible center tab bends towards the notches of the set of notch laminations by the magnet.
12 . The rotor assembly of claim 11 , wherein:
the rotor core includes a plurality of the subset of stacked laminations, and
the flexible tabs of the plurality of the subset of stacked laminations form an array of the flexible tabs along the cavities that are adapted to contact and bias the magnet in the cavity toward an inner surface of the cavity.
13 . The rotor assembly of claim 11 , wherein:
the subset of stacked laminations is arranged at a first end of the rotor core, and
a second tab lamination from among the plurality of tab laminations is provided as an end lamination at a second end of the rotor core opposite of the first end to abut with and retain the magnet.
14 . The rotor assembly of claim 11 , wherein:
each first aperture of the notch lamination has a plurality of the notches, and
each tab lamination includes a plurality of the flexible center tabs that align with the plurality of the notches of the notch lamination.
15 . The rotor assembly of claim 1 , wherein the first side tab is provided at an opposing side of the third aperture as the second side tab.
16 . The rotor assembly of claim 11 , wherein the first side tab is provided at an opposing side of the third aperture as the second side tab.