Miniature centrifuge rotor for high speed applications

Abstract

Miniature centrifuge rotors for high speed applications are described herein. In one aspect, a rotor for a centrifuge, the rotor defining an axis of rotation, and the rotor comprising: a first wound tape defining a diameter, a top edge, and a bottom edge, and extending circumferentially about the axis of rotation; a second wound tape defining a diameter, a top edge, and a bottom edge, the second wound tape extending circumferentially about the axis of rotation; a rotor body extending between the first wound tape and the second wound tape, and at least one of the first wound tape and the second wound tape including a carbon fiber spiral winding, a top edge of the second wound tape being separated from a bottom edge of the first wound tape by a distance as measured along the axis of rotation.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority and the benefit of U.S. Provisional Application No. 63 / 387,761, "Micro - Centrifuge Rotor for High - Speed Application", filed on December 16, 2022, the entire content of which is incorporated herein by reference for any and all purposes. Technical Field

[0003] The present invention generally relates to centrifuge rotors and, more particularly, to micro - centrifuge rotors. Background Art

[0004] Micro - centrifuge rotors are commonly used in laboratory centrifuges (e.g., benchtop centrifuges) to hold samples (e.g., samples in microtubes) during centrifugation. These micro - centrifuge rotors are different in size from general rotors; micro - centrifuge rotors are smaller in size, while general rotors are larger and can accommodate larger volumes of samples. A common rotor structure is a fixed - angle rotor having a solid rotor body with a plurality of unit cavities or chambers that are radially distributed within the rotor body and symmetrically arranged about the axis of rotation. Samples are placed in the unit cavities, and the multiple samples are subjected to centrifugal action.

[0005] Because micro - centrifuge rotors are used in high - speed rotation applications at speeds of thousands of revolutions per minute in centrifuges, the centrifuge rotors must be able to withstand the stresses and strains experienced during high - speed rotation of the loaded rotor. During centrifugation, the rotor with samples loaded into the unit cavities is subjected to large forces consistent with the centrifugal force applied to the sample containers in the direction radially outward from the unit cavities and in the direction along the longitudinal axis of the unit cavities. These forces, in turn, generate significant forces on the rotor body.

[0006] Micro - centrifuge rotors are also typically limited in the speed (e.g., rpm) at which they can rotate. Two main considerations for the rotor speed threshold are rotor weight and rotor composition. Conventional micro - centrifuge rotors are sometimes made of aluminum. Although aluminum provides a certain amount of structural integrity, aluminum is also relatively heavy, which reduces the speed at which aluminum - (or other metal -) based rotors can be driven. Alternative compositions, such as plastics, while lighter, do not have the same structural integrity as aluminum or other metals. Thus, although plastic - based rotors can be driven at higher speeds, they are prone to deterioration or cracking.

[0007] Therefore, considering the dynamic loads experienced during centrifugation, there is a need to provide improved performance. There is also a need for a micro - centrifuge rotor that is manufactured at low cost and designed for high - speed applications. Summary of the Invention

[0008] This document describes a microcentrifuge rotor for high-speed applications. In one aspect, the present disclosure provides a rotor for a centrifuge that defines a rotational axis, and the rotor includes: a first winding tape that defines a diameter, a top edge, and a bottom edge, and the first winding tape extends circumferentially around the rotational axis; a second winding tape that defines a diameter, a top edge, and a bottom edge, and the second winding tape extends circumferentially around the rotational axis; a rotor body that extends between the first winding tape and the second winding tape, and at least one of the first winding tape and the second winding tape includes a carbon fiber spiral winding or a circular winding, and the top edge of the second winding tape is separated from the bottom edge of the first winding tape by a distance as measured along the rotational axis.

[0009] In another aspect, the present disclosure provides a rotor for a centrifuge that defines a rotational axis, and the rotor includes: a rotor body that extends circumferentially around the rotational axis, wherein the rotor body includes: a first end and a second end; an annular portion that extends circumferentially around the rotational axis, wherein the annular portion defines a plurality of holes; and an extension portion that extends circumferentially around the rotational axis, wherein the extension portion extends away from the annular portion and terminates at a bottom end; and a plate that extends circumferentially around the rotational axis and terminates at a distal end and a proximal end, wherein the distal end of the plate contacts the first end of the rotor body and the proximal end of the plate contacts the second end of the rotor body.

[0010] In another aspect, the present disclosure provides a rotor for a centrifuge that defines a rotational axis, and the rotor includes: a rotor body that extends circumferentially around the rotational axis; and a plate that extends circumferentially around the rotational axis and contacts the rotor body; and a plurality of unit inserts, wherein each unit insert is positioned within a respective one of the plurality of holes, wherein each unit insert is configured to receive a centrifuge sample tube, and wherein each unit insert defines a flat bottom end. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] For the purpose of illustrating the present invention, the presently preferred forms are shown in the drawings; however, it is to be understood that the present invention is not limited to the precise arrangements and instrumentalities shown.

[0012] Figure 1 A perspective elevation view of a microcentrifuge rotor in accordance with the present disclosure is depicted.

[0013] Figure 2A and Figure 2B A perspective sectional view of a microcentrifuge rotor in accordance with the present disclosure is depicted.

[0014] Figure 3A and Figure 3BDepicts an exploded cross-sectional view of a micro centrifuge rotor according to the present disclosure.

[0015] Figure 4A and Figure 4B Depicts a perspective view of a micro centrifuge rotor according to the present disclosure. Detailed Description

[0016] It should be understood that, for clarity, certain features of the present invention are described herein in the context of separate embodiments and may also be provided in combination in a single embodiment. Conversely, for brevity, the various features of the present invention described in the context of a single embodiment may also be provided separately or in any sub-combination. Additionally, references to values within a range include each value within that range. Further, the term "comprising" should be understood to have its standard, open-ended meaning but also encompasses "consisting of". For example, a device comprising part A and part B may include parts other than part A and part B, but may also consist only of part A and part B.

[0017] A micro centrifuge rotor is described herein. The rotor may include a rotor body that defines two annular sections about a rotational axis. The first annular section may include a smaller diameter than the second annular section, and a sloped portion may be defined between these annular sections. Each annular section may be wound with windings to provide structural support to the rotor body. The rotor body may define a plurality of holes for receiving sample inserts, which in turn may receive sample vials. The rotor body may also be composed of carbon fiber, which may reduce weight while providing structural integrity.

[0018] Figures 1 to 4B Depicts various views of an exemplary micro centrifuge rotor 100 according to the present disclosure. The micro centrifuge rotor 100 may include a rotor body 105, a plate 110, and a lid assembly 115. The micro centrifuge rotor 100 may be of the type of a benchtop centrifuge rotor. The dimensions of the rotor may be designed to be positioned on a workbench or tabletop (e.g., on a centrifuge motor capable of being positioned on a workbench or tabletop). As an example, the micro centrifuge rotor 100 may be, for example, 6 inches in diameter and 3 inches in height.

[0019] The rotor body 105 may include an outer surface 125 that extends circumferentially about a rotational axis 120. The outer surface 125 may define a first annular portion 130 and a second annular portion 135 that extend circumferentially about the rotational axis 120. The outer surface 125 may terminate at the first annular portion 130 and the second annular portion 135, respectively. In some cases, the first annular portion 130, the second annular portion 135, or both may be substantially parallel to the rotational axis 120. However, those skilled in the art will understand that the widths of the first annular portion 130, the second annular portion 135, or both may be angled relative to the rotational axis.

[0020] The outer surface 125 may further define an intermediate portion 140 that extends circumferentially about the rotational axis 120 and extends between the first annular portion 130 and the second annular portion 135. Additionally, the diameter of the first annular portion 130 may be less than the diameter of the second annular portion 135. Accordingly, the intermediate portion 140 may be angled relative to the rotational axis 120. The intermediate portion 140 may include carbon fiber.

[0021] The rotor body 105 may be formed of carbon fiber. The rotor body 105 may be formed via a molding process such as compression molding, where carbon fiber is formed, placed in a mold, and resin is applied prior to applying a compressive force to the mold to form the rotor body 105. Alternatively, the rotor body may be formed by carding and weaving fiber sheets or mats, each impregnated with a thermosetting resin, and then combining and compression molding them to form the rotor body 105.

[0022] The microcentrifuge rotor 100 may further include a first winding 145 and a second winding 150. The first winding 145 may be wound around a portion of the outer surface 125 and, in particular, around the first annular portion 130. The first winding 145 may substantially cover the entire width of the first annular portion 130, and thus the width of the first winding 145 may be substantially equal to the width of the first annular portion 130. Additionally, the width of the first winding 145 may include an angle relative to the rotational axis 120 similar to that of the first annular portion 130. Accordingly, in the case where the width of the first annular portion 130 is substantially parallel to the rotational axis 120, the width of the first winding 145 may also be substantially parallel to the rotational axis 120.

[0023] The first winding 145 may comprise carbon fiber. The first winding 145 may comprise one or more carbon fiber strands wound around the first annular portion 130. The winding may be substantially perpendicular to the axis of rotation 120 (e.g., between 0.5 degrees and 5 degrees from the vertical direction). In some cases, the winding may be a helical configuration. In some cases, the winding may be performed after the rotor body 105 has been formed (e.g., formed via compression molding). In some cases, the winding may be performed separately from the rotor body 105. For example, the winding may be performed on or in a winding machine. Once wound, the first winding 145 may be cured, for example, via heat curing. In cases where the winding is performed separately from the rotor body 105, once the first winding 145 is cured, the first winding 145 may be positioned on the first annular portion 130. The first winding 145 may be configured to receive forces from the first annular portion 130 during rotation and may support the structural integrity of the microcentrifuge rotor 100. For example, the first winding 145 may be configured to receive forces perpendicular to the axis of rotation 120 when the rotor 100 is operated (e.g., driven).

[0024] The second winding 150 may be wound around a portion of the outer surface 125 and, in particular, around the second annular portion 135. The second winding 150 may substantially cover the entire width of the second annular portion 135, and thus the width of the second winding 150 may be substantially equal to the width of the second annular portion 135. Additionally, the width of the second winding 150 may include an angle relative to the axis of rotation 120 similar to that of the second annular portion 135. Thus, in cases where the width of the second annular portion 135 is substantially parallel to the axis of rotation 120, the width of the second winding 150 may also be substantially parallel to the axis of rotation 120.

[0025] The second winding 150 may be composed of carbon fiber. The second winding 150 may include one or more carbon fiber strands, which are optionally coated with a thermosetting resin and then wound around the second annular portion 135. The winding may be substantially perpendicular to the axis of rotation 120 (e.g., at an angle of 0.5 degrees to 5 degrees from the vertical direction). In some cases, the winding may be in a helical configuration. In some cases, the winding may be performed after the rotor body 105 has been formed (e.g., formed via compression molding). In some cases, the winding may be performed separately from the rotor body 105. For example, the winding may be performed on or in a winding machine. Once wound, the second winding 150 may be cured, for example, via heat curing. In the case where the winding is performed separately from the rotor body 105, once the second winding 150 is cured, the second winding 150 may be positioned on the second annular portion 135. The second winding 150 may be configured to receive forces from the second annular portion 135 during rotation and may support the structural integrity of the microcentrifuge rotor 100. For example, the second winding 150 may be configured to receive a force parallel to the axis of rotation 120 (e.g., downward) when the rotor 100 is operated (e.g., driven).

[0026] Windings 145 and 150 may be configured to receive different force components generated by centrifuge actuation. For example, when activated, the rotor may generate a centrifugal force that radiates radially outward from the center of the rotor. The windings may be arranged to receive different components of the centrifugal force. For example, the centrifugal force may be resolved into a first component that extends along the length direction of the corresponding sample insert 165 and a second component that is perpendicular to the length direction of the corresponding sample insert 165. Each winding may be configured and arranged to receive various force components. For example, the first winding 145 may be arranged near the top end of the sample insert 165 and may be configured to receive the second component of the centrifugal force. Additionally, the second winding 150 may be arranged near the bottom end of the sample insert 165 and may be configured to receive the first component of the centrifugal force.

[0027] The rotor body 105 may further include an internal annular portion 155. The internal annular portion 155 may extend circumferentially around the axis of rotation 120. The internal annular portion 155 may start at the first annular portion 130 and may extend radially inward toward the axis of rotation 120. The internal annular portion 155 may further define a plurality of holes 160. Each hole 160 may be configured to receive a corresponding sample insert 165. The sample insert 165 may be configured to receive a sample vial.

[0028] The rotor body 105 may further include an extension portion 170. The extension portion 170 may extend circumferentially about the rotational axis 120 and may extend from the inner annular portion 155 parallel to (or substantially parallel to) the rotational axis 120. Thus, the extension portion 170 may define a cavity that may be configured to receive a hub. The hub may be configured to be coupled to a drive shaft or a main shaft of the micro centrifuge to drive the micro centrifuge rotor 100. The assembly of the hub to the rotor body may be by press fit or shrink fit.

[0029] The micro centrifuge rotor 100 may further include a plate 110. The plate 110 may extend radially from the rotational axis 120 and circumferentially about the rotational axis. In some cases, the plate 110 may generally form a ring. The plate 110 may be configured to define a proximal end 175 and a distal end 180 that extend circumferentially about the rotational axis 120. The proximal end 175 may further define a cavity for positioning the hub when coupled to the rotor body 105.

[0030] The plate 110 may be formed of carbon fiber. In some cases, the plate 110 may include aluminum and / or stainless steel. The plate 110 may be formed via a molding process such as compression molding, where carbon fiber is formed, placed in a mold, and resin is applied before applying a compressive force to the mold to form the plate 110.

[0031] The plate 110 may be inclined (e.g., in the radial direction) such that the plane defined by the proximal end 175 is different from the plane defined by the distal end 180 (e.g., when coupled to the centrifuge motor, the proximal end 175 is above the distal end 180). Additionally, the plate 110 may be configured to be coupled to the rotor body 105. The distal end 180 of the plate 110 may be configured to be coupled to a second annular portion 135, such as, for example, the inner surface of the second annular portion 135. Additionally, the proximal end 175 of the plate 110 may be configured to be coupled to (or adjacent to) the extension portion 170 of the rotor body 105. Coupling the plate 110 to the rotor body 105 may include applying an adhesive to the coupling points (proximal end 175, distal end 180, first annular portion 130, second annular portion 135, etc.) and curing the adhesive. In some cases, the distal end 180 may further define a protrusion 185. The protrusion 185 may extend distally away from the rotational axis 120 and may allow the rotor body to rest on top of the plate 110 when coupled.

[0032] When assembled, the sample insert 165 can be positioned within a corresponding bore 160 defined by the rotor body 105. The sample insert 165 can include a flat bottom, which can facilitate the alleviation / distribution of forces transmitted from the sample insert to the rotor body 105 and / or the plate 110. Additionally, the rotor body 105 and / or the plate 110 can provide a corresponding flat surface on which the flat bottom of the sample insert 165 rests. For example, the distal end 180 of the plate 110 can include a flared portion that increases in thickness distally away from the axis of rotation 120. This flared portion can provide a flat surface on which the flat bottom of the sample insert 165 rests. In some cases, the bottom of the sample insert 165 can rest on the inner surface of the second annular portion 150. The surface of the second annular portion 150 can be flush or substantially flush with the surface of the distal end 180 of the plate 110; the bottom of the sample insert 165 can rest on these flush surfaces of the second annular portion 150 and the distal end 180 of the plate 110. Figure 3A and Figure 3B Depicts an exploded cross-sectional view of a microcentrifuge rotor 100 in accordance with the present disclosure.

[0033] The sample insert 165 can be composed of a variety of materials. For example, the sample insert 165 can be composed of a thermoplastic polymer (such as polycarbonate). In some cases, the sample insert 165 can be composed of another polymer (such as polyester). In some cases, the sample insert 165 can be composed of acrylic.

[0034] The configuration shown in the figure features a 12x1.5ml rotor with 12 cavities, each cavity capable of accommodating tubes in the range of 1.5ml to 2.0ml. However, other different configurations can be implemented in the rotors described herein, for example, 6x1.5 / 2.0mL, 8x1.5 / 2.0mL, 10x1.5 / 2.0mL, and 14x1.5 / 2.0mL. Additionally, the rotors described herein can be implemented with other configurations having different cavity volumes, which are designed to hold tubes of different volumes (such as 5.0ml, 10ml, 15ml, 50ml, and 100ml) suitable for high-speed applications.

[0035] Exemplary embodiments

[0036] The following embodiments are illustrative only and are not intended to limit the scope of the present disclosure or the appended claims. It should be understood that any part of any one or more embodiments can be combined with any part of any other one or more embodiments.

[0037] Embodiment 1

[0038] A rotor for a centrifuge, the rotor defining a rotational axis, and the rotor comprising: a first winding band defining a diameter, a top edge, and a bottom edge, and the first winding band extending circumferentially about the rotational axis; a second winding band defining a diameter, a top edge, and a bottom edge, and the second winding band extending circumferentially about the rotational axis; a rotor body extending between the first winding band and the second winding band, and at least one of the first winding band and the second winding band comprising a carbon fiber helical winding or a circular winding, the top edge of the second winding band being separated from the bottom edge of the first winding band by a distance as measured along the rotational axis.

[0039] Embodiment 2

[0040] The rotor according to embodiment 1, wherein the diameter of the second winding band is greater than the diameter of the first winding band.

[0041] Embodiment 3

[0042] The rotor according to any one of embodiments 1 to 2, wherein the width of the first winding band is substantially parallel to the width of the second winding band.

[0043] Embodiment 4

[0044] The rotor according to any one of embodiments 1 to 3, wherein the rotor body comprises carbon fiber.

[0045] Embodiment 5

[0046] The rotor according to any one of embodiments 1 to 4, wherein the rotor body terminates in a flared upper lip extending circumferentially about the rotational axis, and wherein the flared upper lip contacts the first winding band.

[0047] Embodiment 6

[0048] The rotor according to any one of embodiments 1 to 5, wherein the rotor body terminates in a bottom portion extending circumferentially about the rotational axis, and wherein the bottom portion contacts the second winding band.

[0049] Embodiment 7

[0050] The rotor according to any one of embodiments 1 to 6, wherein the rotor body defines a plurality of holes, each hole being configured to receive a centrifuge unit insert, the unit insert being configured to receive a centrifuge sample tube.

[0051] Embodiment 8

[0052] A rotor for a centrifuge, the rotor defining a rotational axis, and the rotor comprising: a rotor body that extends circumferentially about the rotational axis, wherein the rotor body comprises: a first end and a second end; an annular portion that extends circumferentially about the rotational axis, wherein the annular portion defines a plurality of holes; and an extension that extends circumferentially about the rotational axis, wherein the extension extends away from the annular portion and terminates at a bottom end; and a plate that extends circumferentially about the rotational axis and terminates at a distal end and a proximal end, wherein the distal end of the plate contacts the first end of the rotor body and the proximal end of the plate contacts the second end of the rotor body.

[0053] Embodiment 9

[0054] The rotor according to embodiment 8, wherein the annular portion further extends radially towards the rotational axis.

[0055] Embodiment 10

[0056] The rotor according to any one of embodiments 8 to 9, the rotor further comprising a plurality of unit inserts, wherein each unit insert is positioned within a respective one of the plurality of holes, wherein each unit insert is configured to receive a centrifuge sample tube, and wherein the bottom end of each unit insert contacts at least one of the distal end of the plate and the first end of the rotor body, the bottom end of the unit insert optionally being flat in construction.

[0057] Embodiment 11

[0058] The rotor according to any one of embodiments 8 to 10, wherein the rotor body, the plate, and the plurality of unit inserts at least partially define a cavity.

[0059] Embodiment 12

[0060] The rotor according to any one of embodiments 8 to 11, wherein the cavity extends circumferentially about the rotational axis.

[0061] Embodiment 13

[0062] The rotor according to any one of embodiments 8 to 12, wherein at least one of the rotor body and the plate comprises carbon fiber.

[0063] Embodiment 14

[0064] A rotor according to any one of embodiments 8 to 13, wherein the rotor is configured to operate with a microcentrifuge.

[0065] Embodiment 15

[0066] A rotor for a centrifuge, the rotor defining a rotational axis, and the rotor comprising: a rotor body that extends circumferentially about the rotational axis; and a plate that extends circumferentially about the rotational axis and contacts the rotor body; and a plurality of unit inserts, wherein each unit insert is positioned within a respective one of the plurality of holes, wherein each unit insert is configured to receive a centrifuge sample tube, and wherein each unit insert defines a flat bottom end.

[0067] Embodiment 16

[0068] A rotor according to embodiment 15, wherein the bottom end of each unit insert contacts at least one of the plate and the rotor body.

[0069] Embodiment 17

[0070] A rotor according to any one of embodiments 15 to 16, wherein the bottom end of each unit insert contacts the distal end of the plate and the first end of the rotor body.

[0071] Embodiment 18

[0072] A rotor according to any one of embodiments 15 to 17, the rotor further comprising a first winding strip that defines a diameter, a top edge, and a bottom edge, and the first winding strip extends circumferentially about the rotational axis and contacts the rotor body.

[0073] Embodiment 19

[0074] A rotor according to any one of embodiments 15 to 18, wherein the plate further defines a protrusion extending therefrom, and wherein the protrusion contacts the rotor body and the first winding strip.

[0075] Embodiment 20

[0076] A rotor according to any one of embodiments 15 to 19, wherein the plate defines a flared portion that contacts the bottom end of each of the plurality of unit inserts.

Claims

1. A rotor for a centrifuge, the rotor defining a rotational axis, and the rotor comprising: A first winding tape, the first winding tape defining a diameter, a top edge and a bottom edge, and the first winding tape extending circumferentially about the rotational axis; A second winding tape, the second winding tape defining a diameter, a top edge and a bottom edge, and the second winding tape extending circumferentially about the rotational axis; A rotor body, the rotor body extending between the first winding tape and the second winding tape; and The top edge of the second winding tape is separated from the bottom edge of the first winding tape by a distance as measured along the rotational axis.

2. The rotor according to claim 1, wherein, The diameter of the second winding tape is greater than the diameter of the first winding tape.

3. The rotor according to claim 1, wherein, The width of the first winding tape is substantially parallel to the width of the second winding tape.

4. The rotor according to any one of claims 1, wherein, The rotor body comprises carbon fiber.

5. The rotor according to any one of claims 1, wherein The rotor body terminates in a flared upper lip extending circumferentially about the rotational axis, and wherein the flared upper lip contacts the first winding tape.

6. The rotor according to any one of claims 1, wherein The rotor body terminates in a bottom portion extending circumferentially about the rotational axis, and wherein the bottom portion contacts the second winding tape.

7. The rotor according to any one of claims 1, wherein The rotor body defines a plurality of holes, wherein each hole is configured to receive a centrifuge unit insert, and the unit insert is configured to receive a centrifuge sample tube.

8. A rotor for a centrifuge, the rotor defining a rotational axis, and the rotor comprising: A rotor body, the rotor body extending circumferentially about the rotational axis, wherein the rotor body comprises: A first end and a second end; An annular portion, the annular portion extending circumferentially about the rotational axis, wherein the annular portion defines a plurality of holes; and An extension, the extension extending circumferentially about the rotational axis, wherein the extension extends away from the annular portion and terminates at a bottom end; and A plate, the plate extending circumferentially about the rotational axis and terminating at a distal end and a proximal end, wherein the distal end of the plate contacts the first end of the rotor body and the proximal end of the plate contacts the second end of the rotor body.

9. The rotor according to claim 8, wherein, The annular portion further extends radially towards the rotational axis.

10. The rotor according to claim 8, the rotor further comprising a plurality of unit inserts, wherein each unit insert is positioned within a respective one of the plurality of holes, wherein each unit insert is configured to receive a centrifuge sample tube, and wherein the bottom end of each unit insert contacts at least one of the distal end of the plate and the first end of the rotor body, and the bottom end of the unit insert is optionally flat in construction.

11. The rotor according to claim 10, wherein, The rotor body, the plate and the plurality of unit inserts at least partially define a cavity.

12. The rotor according to claim 11, wherein, The cavity extends circumferentially about the rotational axis.

13. The rotor according to any one of claims 8, wherein, At least one of the rotor body and the plate comprises carbon fiber.

14. The rotor according to any one of claims 8, wherein, The rotor is configured to operate with a microcentrifuge.

15. A rotor for a centrifuge, the rotor defining a rotational axis, and the rotor comprising: A rotor body that extends circumferentially about the axis of rotation; and a plate that extends circumferentially about the axis of rotation and contacts the rotor body; as well as a plurality of unit inserts, wherein each unit insert is positioned within a respective one of the plurality of holes, wherein each unit insert is configured to receive a centrifuge sample tube, and wherein each unit insert defines a flat bottom end.

16. The rotor according to claim 15, wherein, The bottom end of each unit insert contacts at least one of the plate and the rotor body.

17. The rotor according to claim 16, wherein, The bottom end of each unit insert contacts the distal end of the plate and the first end of the rotor body.

18. The rotor according to any one of claims 15, further comprising a first winding strip that defines a diameter, a top edge, and a bottom edge, and that extends circumferentially about the axis of rotation and contacts the rotor body.

19. The rotor according to claim 18, wherein, The plate further defines a protrusion extending therefrom, and wherein the protrusion contacts the rotor body and the first winding strip.

20. The rotor according to any one of claims 15, wherein, The plate defines a flared portion that contacts the bottom end of each of the plurality of unit inserts.

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