NOISE REDUCTION STRUCTURES FOR ELECTRICAL MACHINES
An electrical machine rotor or stator having a plurality of salient poles and a barrier that inhibits the flow of air along an axial path between the environment outside the rotor or stator and the space between adjacent pairs of the poles. The barrier serves to reduce acoustic noise.
1 . An electrical machine component comprising:
a plurality of salient poles, projecting along a radial axis of the component, that each conveys an applied electromagnetic flux; and
an electrically and magnetically inert solid material within a space between a rotationally-adjacent pair of salient poles.
2 . The electrical machine component of claim 1 , wherein the inert material is epoxy.
3 . The electrical machine component of claim 1 , wherein the inert material fills the space between the adjacent pair of poles.
4 . The electrical machine component of claim 1 , wherein a distal periphery of the inert material is coextensive with the distal periphery of the adjacent pair of poles.
5 . The electrical machine component of claim 1 , wherein the inert material has a length that is coextensive with that of the component along its axis of rotation.
6 . The electrical machine component of claim 1 , wherein the component is a rotor of an electrical machine.
7 . The electrical machine component of claim 1 , wherein the component is a stator of an electrical machine.
8 . A machine rotor comprising:
a plurality of salient poles, projecting along a radial axis of the rotor, that each conveys an applied electromagnetic flux;
a space between a rotationally-adjacent pair of salient poles that inhibits conveyance of an applied electromagnetic flux; and
first and second opposing structures that each extends at least partially across the rotationally-adjacent pair of poles and has an outward salient projection along the radial axis of the rotor.
9 . The machine rotor of claim 8 , further comprising an electrically and magnetically inert solid material within the space bounded by the rotationally-adjacent pair of poles and the first and second opposing structures.
10 . The machine rotor of claim 8 , wherein the outer radial-periphery of each of the first and second opposing structures is coextensive with that of the salient poles.
11 . The machine rotor of claim 8 , wherein the first and second opposing structures extend entirely across the rotationally-adjacent pair of poles.
12 . The machine rotor of claim 8 , wherein:
the rotor comprises first laminations that are rotationally aligned so as to form the salient poles and spaces there between,
the rotor further comprises second laminations having salient poles and spaces there between that constitute the first and second opposing structures, and
the salient poles of the second laminations are rotationally offset from those of the first laminations.
13 . The machine rotor of claim 12 , wherein the second laminations each has a smaller pole arc than a pole arc of a first lamination.
14 . The machine rotor of claim 13 , wherein a pole of one of the second laminations is offset from all poles of another second lamination.
15 . The machine rotor of claim 13 , wherein the poles of each second lamination are offset from those of all other second laminations.
16 . The machine rotor of claim 12 , wherein:
the second laminations each has a larger pole arc than the pole arcs of the first laminations, and
the first and second opposing structures extend entirely across the rotationally-adjacent pair of poles.
17 . The machine rotor of claim 14 , wherein:
a set of two second laminations are disposed on each end of a stack of first laminations, and
for each set of second laminations, a pole of one of the second laminations is offset from all poles of the other second lamination.
18 . The machine rotor of claim 17 , wherein the first laminations are identical and the second laminations are identical.
19 . An electrical machine comprising:
an electrical component having a plurality of salient poles, projecting along a radial axis of the component, that each conveys an applied electromagnetic flux; and
an annulus disposed outside a first axial surface of the electrical component, wherein
the annulus is a barrier between a space outside the axial surface of the electrical component and a space between a rotationally-adjacent pair of poles.
20 . The electrical machine of claim 19 , wherein the distal periphery of the annulus is coextensive with that of the rotationally-adjacent pair of poles.
21 . The electrical machine of claim 19 , wherein the electrical component is a rotor.
22 . The electrical machine of claim 19 , wherein the electrical component is a stator.
23 . The electrical machine rotor of claim 19 , further comprising an electrically and magnetically inert solid material within the space bounded by the rotationally-adjacent pair of poles and annulus.
24 . The electrical machine of claim 19 , further comprising:
another annulus disposed outside a second axial surface of the electrical component that is opposite the first axial surface along the axial length of the electrical component, wherein
the other annulus is a barrier between a space outside the second axial surface of the electrical component and a space between a rotationally-adjacent pair of poles.
25 . The electrical machine of claim 19 , wherein the radial length between the inner and outer radii of the annulus is substantially equal to the radial length of the poles.
26 . The electrical machine of claim 19 further comprising:
a stator having a plurality of salient poles, projecting along a radial axis of the stator, that each conveys an applied electromagnetic flux; and
another annulus disposed outside a first axial surface of the stator, wherein
the electrical component is a rotor.
27 . The electrical machine of claim 19 further comprising:
a stator having a plurality of salient poles, projecting along a radial axis of the stator, that each conveys an applied electromagnetic flux; and
an electrically and magnetically inert solid material within space bounded by a rotationally-adjacent pair of the stator poles, wherein
the electrical component is a rotor.
28 . The electrical machine of claim 19 further comprising:
a rotor having a plurality of salient poles, projecting along a radial axis of the rotor, that each conveys an applied electromagnetic flux; and
an electrically and magnetically inert solid material within a space bounded by a rotationally-adjacent pair of the rotor poles, wherein
the electrical component is a stator.
29 . The electrical machine of claim 19 further comprising:
a rotor having a plurality of salient poles, projecting along a radial axis of the rotor, that each conveys an applied electromagnetic flux;
a space between a rotationally-adjacent pair of rotor poles that inhibits conveyance of an applied electromagnetic flux; and
first and second opposing structures that each extends at least partially across the rotationally-adjacent pair of poles and has an outward salient projection along the radial axis of the rotor, wherein
the electrical component is a stator.