Advanced flywheel hub and method

A hub for use in a high-speed flywheel rotor assembly as part of an overall flywheel system, the rotor assembly including a shaft that supports said hub which, in turn, supports a rim such that the rotor assembly exhibits at least one predetermined bending mode frequency, said hub comprising:

• an annular hub body defining an axis of rotation and having a hub length extending along the axis of rotation from a first end to a second, opposing end, said first end defining an inside diameter for engaging an outside diameter of said shaft for co-rotation therewith and said second end defining an outside diameter for engaging an inside diameter of said rim, said annular hub body formed in a layered configuration at least including a first layer that includes at least first fibers supported in a first matrix such that the first fibers form at least a majority of the fibers that make up the first layer and the first fibers are limited to one fiber orientation along the axis of rotation and a second layer that annularly surrounds the first layer and which includes at least second fibers supported in a second matrix such that the second fibers form at least a majority of the fibers that make up the second layer and the second fibers are limited to another fiber orientation that is transverse to the axis of rotation,
• wherein said first layer and said second layer exhibit a first radial stiffness and a second radial stiffness, respectively, as a resistance to expansion in a radial direction responsive to a rotation of said rotor assembly, and the first and second layers are configured to cooperate with one another so that said hub body exhibits a radial hub body stiffness that varies along the length of said hub body such that said second end of said hub body expands, responsive to said operational rotation, for maintaining said engagement with said inside diameter of said rim, at least up to and including a predetermined maximum rotational speed of said rotor assembly.

A system including a high-speed flywheel rotor assembly as part of an overall flywheel system, the rotor assembly including a shaft that supports a hub which, in turn, supports a rim such that the rotor assembly exhibits a predetermined bending mode frequency, and said rim exhibits a radial rim stiffness as a resistance to expansion in a radial direction responsive to centrifugal force induced by an operational rotation of the rotor assembly, an improvement comprising:

• said hub including an annular elongated hub body in a layered configuration at least including a first material layer that consists of fibers supported in a first matrix having a majority of the fibers limited to a fiber orientation extending along an axis of rotation,
• wherein the annular elongated hub body comprises a second material layer that annularly surrounds the first material layer,
• wherein said first material layer and said second material layer exhibit a first radial stiffness and a second radial stiffness, respectively, as a resistance to expansion in a radial direction responsive to a rotation of said rotor assembly, and the first material layer and second material layer are configured to cooperate with one another so that said hub body exhibits a radial hub body stiffness that varies along the length of said hub body such that said second end of said hub body expands, responsive to said operational rotation, for maintaining said engagement with said inside diameter of said rim, at least up to and including a predetermined maximum rotational speed of said rotor assembly.

A method for producing a hub for use in a high-speed flywheel rotor assembly as part of an overall flywheel system, the rotor assembly including a shaft that supports said hub which, in turn, supports a rim such that the rotor assembly exhibits a predetermined bending mode frequency, and said rim exhibits a radial rim stiffness as a resistance to expansion in a radial direction responsive to centrifugal force induced by an operational rotation of the rotor assembly, said method comprising:

• forming an annular elongated hub body at least including a first layer that includes at least first fibers supported in a first matrix with the first fibers forming at least a majority of the fibers that make up the first layer and orienting the first fibers limited to one fiber orientation along an axis of rotation and annularly surrounding the first layer with a second layer, the second layer includes at least second fibers supported in a second matrix with the second fibers forming at least a majority of the fibers that make up the second layer and orienting the second fibers limited to another fiber orientation that is transverse to the axis of rotation such that the hub body is formed to define the axis of rotation and having a hub length extending along the axis of rotation from a first end to a second, opposing end;
• and
• defining an inside diameter at said first end for receiving said shaft for co-rotation therewith and an outside diameter at said second end for engaging an inside diameter of said rim,
• wherein said first layer and said second layer exhibit a first radial stiffness and a second radial stiffness, respectively, as a resistance to expansion in a radial direction responsive to a rotation of said rotor assembly, and the first and second layers are configured to cooperate with one another so that said hub body exhibits a radial hub body stiffness that varies along the length of said hub body such that said second end of said hub body expands, responsive to said operational rotation, for maintaining said engagement with said inside diameter of said rim, at least up to and including a predetermined maximum rotational speed of said rotor assembly.

A In a method for producing a hub for use in a high-speed flywheel rotor assembly as part of an overall flywheel system, the rotor assembly including a shaft that supports said hub which, in turn, supports a rim such that the rotor assembly exhibits a predetermined bending mode frequency, and said rim exhibits a radial rim stiffness as a resistance to expansion in a radial direction responsive to centrifugal force induced by an operational rotation of the rotor assembly, an improvement comprising:

• forming an annular elongated hub body in a layered configuration at least including a first material layer that consists of fibers supported in a first matrix having a majority of the fibers limited to a fiber orientation extending along an axis of rotation,
• wherein the annular elongated hub body comprises a second material layer that annularly surrounds the first material layer,
• wherein said first material layer and said second material layer exhibit a first radial stiffness and a second radial stiffness, respectively, as a resistance to expansion in a radial direction responsive to a rotation of said rotor assembly, and the first material layer and second material layer are configured to cooperate with one another so that said hub body exhibits a radial hub body stiffness that varies along the length of said hub body such that said second end of said hub body expands, responsive to said operational rotation, for maintaining said engagement with said inside diameter of said rim, at least up to and including a predetermined maximum rotational speed of said rotor assembly.