Electric machine with multi-part trapezoidal teeth
An electric machine may include an stator and a rotatable rotor. At least one of the stator or the rotor may include a plurality of multi-part trapezoidal teeth with an electromagnetic coil disposed around each tooth.
1 . A radial flux electric machine, comprising:
a rotor configured to rotate about an axis of rotation;
a plurality of electromagnetic coils;
a stator including an annular stator ring extending about the axis of rotation, wherein the annular stator ring is a ring-shaped structure that extends about the axis of rotation as a singular structure; and
a plurality of multi-part teeth circumferentially arranged on the annular stator ring, each multi-part tooth of the plurality of multi-part teeth including a core tooth-portion integrally formed with and extending radially from the annular stator ring and at least one additional tooth-portion separate from the annular stator ring,
wherein core tooth-portions of the plurality of multi-part teeth are circumferentially spaced apart from each other and the at least one additional tooth-portion of each multi-part tooth is disposed on an external surface of the core tooth-portion of that multi-part tooth, the core tooth-portion and the at least one additional tooth-portion being coupled together using an adhesive, wherein a difference between coefficients of thermal expansion of materials of the core tooth-portion, the at least one additional tooth-portion, and the adhesive is less than about 20%, and
wherein each coil of the plurality of electromagnetic coils is mounted on a different multi-part tooth of the plurality of multi-part teeth such that each coil surrounds a corresponding core tooth-portion of the multi-part tooth with a gap between the coil and the core tooth-portion, and the at least one additional tooth-portion is disposed in the gap.
2 . The electric machine of claim 1 , wherein the annular stator ring includes two mirror-symmetric halves coupled together along a plane of symmetry perpendicular to the axis of rotation.
3 . The electric machine of claim 2 , wherein the two mirror-symmetric halves are attached together along the plane of symmetry using an adhesive material.
4 . The electric machine of claim 2 , wherein the annular stator ring includes a soft magnetic composite (SMC).
5 . The electric machine of claim 1 , wherein the at least one additional tooth-portion includes a pair of additional tooth portions.
6 . The electric machine of claim 1 , wherein the annular stator ring includes multiple axially stacked annular rings, and wherein at least two of the stacked annular rings are made of a soft magnetic composite (SMC).
7 . The electric machine of claim 1 , wherein the stator is positioned radially inwards of the rotor and the core tooth-portion of each multi-part tooth extends radially outward from the annular stator ring.
8 . The electric machine of claim 1 , wherein the stator is positioned radially outwards of the rotor and the core tooth-portion of each multi-part tooth extends radially inward from the annular stator ring.
9 . The electric machine of claim 1 , wherein a cross-sectional shape of the core tooth-portion and the at least one additional tooth-portion of each multi-part tooth along a plane perpendicular to a radial direction is substantially rectangular.
10 . The electric machine of claim 9 , wherein a cross-sectional shape of the at least one additional tooth-portion along a plane perpendicular to the axis of rotation is substantially triangular.
11 . The electric machine of claim 9 , wherein a cross-sectional shape of each multi-part tooth of the plurality of multi-part teeth along a plane perpendicular to the axis of rotation is substantially trapezoidal.
12 . The electric machine of claim 1 , wherein the at least one additional tooth-portion includes a pair of additional tooth-portions arranged symmetrically on opposite sides of the core tooth-portion.
13 . The electric machine of claim 12 , wherein the pair of additional tooth-portions are arranged symmetrically about a plane perpendicular to the axis of rotation.
14 . The electric machine of claim 1 , wherein the at least one additional tooth-portion of each multi-part tooth is wedged between an internal surface of a coil of the plurality of electromagnetic coils and an external surface of the core tooth-portion.
15 . The electric machine of claim 1 , wherein a coil of the plurality of electromagnetic coils surrounds the core tooth-portion of each multi-part tooth such that at least two gaps are formed between an inner surface of the coil and opposite sides of the core tooth-portion, and wherein the at least one additional tooth-portion includes at least two additional tooth-portions disposed in a different gap of the at least two gaps.
16 . The electric machine of claim 1 , wherein a cross-section of each multi-part tooth of the plurality of multi-part teeth in a plane perpendicular to a radial direction has a rectangular shape.
17 . The electric machine of claim 1 , wherein the electric machine is an electric motor or an electric generator.
18 . A radial flux electric machine, comprising:
a rotor configured to rotate about an axis of rotation;
a plurality of electromagnetic coils; and
a stator having an annular stator ring extending about the axis of rotation as a singular structure and a plurality of core tooth-portions integrally formed with and symmetrically arranged on the annular stator ring about the axis of rotation to define a circumferential gap between adjacent core tooth-portions and extending in a radial direction,
wherein the stator includes a plurality of multi-part teeth with each tooth of the plurality of multi-part teeth including one core tooth-portion of the plurality of core tooth-portions and a pair of additional tooth-portions non-integrally formed with and attached to opposite external surfaces of the one core tooth-portion using an adhesive, wherein a difference between coefficients of thermal expansion of materials of the one core tooth-portion, the additional tooth-portions, and the adhesive is less than about 20%, and
wherein a cross-sectional shape of each tooth of the plurality of multi-part teeth in a plane perpendicular to the axis of rotation is substantially trapezoidal.
19 . The electric machine of claim 18 , wherein the pair of additional tooth-portions are symmetrically positioned about a plane perpendicular to the axis of rotation.