Thermally matched composite sleeve
View Patent ↗A sleeve about an electric machine rotor core and the plurality of permanent magnets has a fiber-reinforced composite layer about the rotor core and the plurality of permanent magnets. At least a portion of the sleeve about the rotor core and the permanent magnets has a coefficient of thermal expansion that is substantially equal to the aggregate coefficient of thermal expansion of the rotor core and the plurality of permanent magnets.
1. A rotor for an electrical machine comprising:
a rotor core substantially comprised of a first material;
a plurality of permanent magnets carried on the rotor core, the plurality of permanent magnets substantially comprised of a second material that is different from the first material; and
a sleeve about the rotor core and the plurality of permanent magnets the sleeve comprising a fiber-reinforced composite layer about the rotor core and the plurality of permanent magnets, the fiber-reinforced composite layer comprising:
a plurality of elongate fibers,
a polymer binder that, together with the plurality of elongate fibers, provides a majority of the support retaining the plurality of permanent magnets to the rotor core, an aggregate effective coefficient of thermal expansion of the elongate fibers and the polymer binder being disparate from the aggregate effective coefficient of thermal expansion of the plurality of permanent magnets, and
an additional doping material, at least a portion of the sleeve about the rotor core and the permanent magnets having a coefficient of thermal expansion that is substantially equal to the coefficient of thermal expansion of the plurality of permanent magnets.
2. The rotor of claim 1 , wherein the additional material comprises at least one of at least one of ceramic or glass fillers in the form of at least one of fibers or powder.
3. The rotor of claim 1 , wherein the fiber-reinforced composite layer comprises a plurality of elongate fibers and a polymer binder, and the fibers comprise at least one of ceramic, glass, or polymeric fibers.
4. The rotor of claim 1 , wherein the at least a portion of the sleeve about the rotor core and the permanent magnets is substantially comprised of carbon fiber-reinforced composite.
5. The rotor of claim 4 , wherein the rotor core is substantially comprised of metal.
6. The rotor of claim 1 , wherein the sleeve provides a majority of the support retaining the plurality of permanent magnets to the rotor core.
7. The rotor of claim 1 , further comprising a fiber-reinforced composite layer having a coefficient of thermal expansion different than the coefficient of thermal expansion of the permanent magnets.
8. The rotor of claim 7 , wherein the fiber-reinforced composite layer having a coefficient of thermal expansion different than the coefficient of thermal expansion of the permanent magnets resides radially outward from the first mentioned fiber-reinforced composite layer.
9. The rotor of claim 1 , wherein the fiber-reinforced composite layer has a different coefficient of thermal expansion at different locations along a length of the sleeve.
10. A rotor for an electrical machine comprising:
a rotor core substantially comprised of a first material;
a plurality of permanent magnets carried on the rotor core, the plurality of permanent magnets substantially comprised of a second material that is different from the first material; and
a sleeve about the rotor core and the plurality of permanent magnets, the sleeve comprising a fiber-reinforced composite layer about the rotor core and the plurality of permanent magnets, the fiber-reinforced composite layer comprising:
a plurality of elongate fibers,
a polymer binder that, together with the plurality of elongate fibers, provides a majority of the support retaining the plurality of permanent magnets to the rotor core, an aggregate effective coefficient of thermal expansion of the elongate fibers and the polymer binder being disparate from the aggregate effective coefficient of thermal expansion of the plurality of permanent magnets, and
an additional doping material, at least a portion of the sleeve about the rotor core and the permanent magnets having a coefficient of thermal expansion that is substantially equal to the aggregate coefficient of thermal expansion of the rotor core and the plurality of permanent magnets.
11. The rotor of claim 10 , wherein the additional material comprises at least one of ceramic or glass fillers in the form of at least one of fibers or powder.
12. The rotor of claim 10 , wherein the fiber-reinforced composite layer comprises a plurality of elongate fibers and a polymer binder, and the fibers comprise at least one of ceramic, glass, or polymeric fibers.
13. The rotor of claim 10 , wherein the at least a portion of the sleeve about the rotor core and the permanent magnets is substantially comprised of carbon fiber-reinforced composite.
14. The rotor of claim 13 , wherein the rotor core is substantially comprised of metal.
15. A method of retaining elements of an elongate electric machine rotor, the method comprising:
retaining a plurality of permanent magnets to a core of the rotor with a sleeve comprising a fiber-reinforced composite layer, the fiber-reinforced composite layer comprising:
a plurality of elongate fibers,
a polymer binder that, together with the plurality of elongate fibers, provides a majority of the support retaining the plurality of permanent magnets to the rotor core, an aggregate effective coefficient of thermal expansion of the elongate fibers and the polymer binder being disparate from an aggregate effective coefficient of thermal expansion of the plurality of permanent magnets, and
an additional doping material, the fiber-reinforced composite layer having a coefficient of thermal expansion that is substantially equal to the coefficient of thermal expansion of the permanent magnets; and
expanding the fiber-reinforced composite layer substantially along the length of the core of the rotor in response to a change in temperature in approximately the same amount as the permanent magnets expand along the length of the core of the rotor in response to the change temperature.
16. The method of claim 15 , wherein the additional material comprises at least one of ceramic or glass fillers in the form of at least one of fibers or powder.
17. The method of claim 15 , wherein the fiber-reinforced composite layer comprises a plurality of elongate fibers and a polymer binder, and the fibers comprise at least one of ceramic, glass, or polymeric fibers.
18. The method of claim 15 , wherein the core substantially comprises metal.