Polymetallic mechanical retention hoop and method of manufacture thereof

Abstract

The retaining structure can be made using two or more different materials (e.g., one magnetic material and one non-magnetic material) as a composite structure. The retaining structure can include a cylindrical hoop with one or more magnetic regions tangentially alternating with one or more non-magnetic regions configured to surround and retain the multiple magnets on the rotor, the one or more magnetic regions aligned with each of the multiple magnets, and the one or more non-magnetic regions aligned with one or more areas between the multiple magnets on the rotor. The magnetic material allows magnetic flux from the permanent magnets to flow to the stator, and the non-magnetic portion reduces leakage of magnetic flux to adjacent permanent magnets through the use of the non-magnetic material. The retaining structure can be manufactured using a hot isostatic pressing process.

Description

[Background technology]

[0001]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 244,558, entitled "MULTI-METALLIC Mechanical Retention Hoop and Techniques for Manufacturing Thereof," filed September 15, 2021, and is hereby incorporated by reference in its entirety for all purposes.

[0002]

[0002] Electric motors use a rotor assembly with multiple permanent magnets attached to a rotor rim to form a magnetic moment arm and can generate torque. Alternating current can flow through a stator assembly which creates an induced magnetic field that interacts with the permanent magnets attached to the rotor assembly. A magnetic air gap exists between the permanent magnets on the rotor assembly and the stator assembly. This interaction generates a force on the shaft of the electric motor, generating torque. Various techniques (e.g., glue, fasteners) have been used to hold the permanent magnets to the rotor rim. Some techniques (e.g., glue) may be unsuitable for use in high speed machines.

[0003]

[0003] Current designs may include a mechanical retaining structure made of magnetic or non-magnetic material to hold the magnets. Using a completely magnetic material in the retaining structure may result in flux leakage between the area above the permanent magnets and adjacent permanent magnets, reducing the magnetic flux coupled from the rotor to the stator and reducing the power output of the motor. Using a completely non-magnetic material in the retaining structure increases the magnetic air gap or clearance between the magnet and the stator assembly, thereby reducing the strength of the magnetic flux reaching the stator and ultimately reducing the maximum power output capability of the motor. Thus, there is a need in the art for improved methods and systems related to electric motors. Summary of the Invention

[0004]

[0004] Embodiments of the present invention generally relate to methods and systems for electric motors and generators. More specifically, a retaining structure can be created using two or more different materials (e.g., one magnetic material and one non-magnetic material) to form a composite structure in which the dissimilar materials are bonded together. The retaining structure can include a ring with one or more magnetic regions tangentially alternating with one or more non-magnetic regions configured to surround and retain a plurality of magnets to a rotor, the one or more magnetic regions aligned with each of the plurality of magnets, and the one or more non-magnetic regions aligned with one or more areas between the plurality of magnets on the rotor. The magnetic material allows magnetic flux from the permanent magnets to flow to the stator, and the non-magnetic portion uses the non-magnetic material to reduce leakage of magnetic flux to adjacent permanent magnets. The retaining structure can be formed using composite materials (e.g., carbon fiber or fiberglass materials), steel cylinders (e.g., non-magnetic cans), or other metallic materials.

[0005] In various embodiments, the cylindrical hoop can provide a continuous magnetic gap between the plurality of magnets and the one or more magnetic regions of the stator while reducing magnetic flux leakage across the one or more non-magnetic regions. In various embodiments, the one or more magnetic regions and the one or more non-magnetic regions form a stave of the cylindrical hoop.

[0006] In addition to holding the magnets to the rotor rim against the radial and tangential forces generated by the rotating rotor, the cylindrical hoop can be sized to provide a preload force to the magnets of the rotor. The preload force can maintain enough friction on the rotor assembly so that the magnets do not spin when the machine is transmitting torque. The retention structure can also prevent the magnets from dislodging at high speeds and reduce the pressure the magnets exert on the internal structure of the pole retention structure.

[0007] In some aspects, the retaining structure includes a cylindrical hoop including one or more magnetic regions tangentially alternating with one or more non-magnetic regions configured to surround and retain the multiple magnets on the rotor. The cylindrical hoop can be formed by a hot isostatic pressing process. The one or more magnetic regions can each be aligned with one of the multiple magnets, and the one or more non-magnetic regions can each be aligned with one or more areas between the multiple magnets on the rotor.

[0008]

[0008] In some aspects, the cylindrical hoop provides a continuous magnetic gap between the multiple magnets and one or more magnetic regions of the stator while reducing magnetic flux leakage across one or more non-magnetic regions.

[0009] In some embodiments, the one or more magnetic regions and the one or more non-magnetic regions form a stave of a cylindrical hoop.

[0010] In some aspects, the cylindrical hoop is sized to provide a preload force to the multiple magnets of the rotor.

[0011] In some embodiments, the magnetic region or regions are a combination of materials forming different layers.

[0012] In some embodiments, the one or more nonmagnetic regions are a combination of materials forming different layers.

[0013] In some aspects, the magnetic regions are formed with at least one of the one or more magnetic regions at a crowned outer surface to shape the magnetic flux lines of the multiple magnets.

[0014] In some embodiments, the inner surface of the cylindrical hoop is not circular, but is sized to accommodate rectangular magnets or other non-circular segmented magnet configurations.

[0015] In some aspects, the exterior surface of the cylindrical hoop comprises a continuous magnetic material and a non-magnetic material.

[0016] In some aspects, an electric machine includes a housing, a rotor, and a stator. The electric machine can be an electric motor or a generator. The rotor can include a plurality of permanent magnets held by a cylindrical retaining sleeve including one or more magnetic regions tangentially alternating with one or more non-magnetic regions configured to surround and retain the plurality of magnetic bodies on the rotor. The one or more magnetic regions can be aligned with each of the plurality of magnets, and the one or more non-magnetic regions are aligned with one or more areas between the plurality of magnets on the rotor. The stator can surround the rotor with an air gap defined between the cylindrical retaining sleeve and the plurality of magnetic regions on the stator.

[0017]

[0017] In some aspects, the cylindrical retaining sleeve can provide a continuous radial magnetic gap between the multiple permanent magnets and one or more magnetic regions of the stator while reducing magnetic flux leakage across one or more non-magnetic regions.

[0018] In some embodiments, the one or more magnetic regions and the one or more non-magnetic regions form staves of a cylindrical retaining sleeve.

[0019] In some aspects, the cylindrical retaining sleeve is sized to provide a preload force to the plurality of permanent magnets of the rotor.

[0020] In some embodiments, the magnetic region or regions are a combination of materials forming different layers.

[0021] In some embodiments, the non-magnetic region or regions are a combination of materials forming different layers.

[0022] In some embodiments, the magnetic regions are formed at least one of the one or more magnetic regions at a crowned outer surface for shaping the magnetic flux lines of the plurality of permanent magnets.

[0023] In some embodiments, the inner surface of the cylindrical retaining sleeve is sized to accommodate a rectangular magnet rather than a circular one.

[0024] In some aspects, the outer surface of the cylindrical retaining sleeve comprises a continuous magnetic material and a non-magnetic material.

[0025]

[0025] In some aspects, a method of forming a retaining structure including magnetic and non-magnetic regions can include providing a mold for receiving at least one powder for compaction. The at least one powder can include either a magnetic material or a non-magnetic material. The method can include positioning a shape-controlling element along at least one wall of the mold. The shape-controlling element can be configured to control deformation of the mold during hot isostatic pressing. The shape-controlling element is positioned along one or more walls of the mold. The method can include deforming the mold while compacting the at least one powder during hot isostatic pressing to form a cylindrical hoop structure.

[0026] In some aspects, the magnetic regions are formed using a solid material and the non-magnetic regions are formed using one or more powders comprising the non-magnetic material.

[0027] In some aspects, the non-magnetic regions are formed using a solid material and the magnetic regions are formed using at least one powder comprising a magnetic material.

[0028] In some embodiments, the non-magnetic and magnetic regions are formed using at least one powder including a magnetic material and a non-magnetic material.

[0029] In some embodiments, the non-magnetic and magnetic regions are formed using solid state materials.

[0030] In some aspects, the method can include inserting an interface material between the magnetic and non-magnetic regions, the interface material inhibiting carbon migration during hot isostatic pressing.

[0031] In some aspects, the method can include forming a mechanical geometric joint at the boundary between the magnetic and non-magnetic regions.

[0032] In some aspects, a method of forming a retention structure including magnetic and non-magnetic regions can include disposing one or more magnetic materials on one or more magnets of a rotor assembly. The method can include disposing one or more non-magnetic materials on one or more spacers. The spacers can be disposed between the one or more magnets. The method can include welding an edge of the one or more magnetic materials to an edge of the one or more non-magnetic materials to form a cylindrical retention structure sized to fit around the one or more magnets of the rotor assembly.

[0033]

[0033] In some aspects, a method of forming a retaining structure including magnetic and non-magnetic regions can include disposing one or more magnetic materials on one or more magnets of a rotor assembly. The method can include disposing one or more non-magnetic materials on one or more spacers. The spacers can be disposed between the one or more magnets. The method can include forming a cylindrical retaining structure sized to fit around the one or more magnetic materials and the one or more non-magnetic materials. Forming the cylindrical retaining structure can be accomplished by a three-dimensional printing process.

[0034]

[0034] In some aspects, the magnetic regions can be formed using a solid material and the non-magnetic regions can be formed using one or more powders comprising one or more non-magnetic materials.

[0035] In some aspects, the non-magnetic regions can be formed using a solid material and the magnetic regions can be formed using at least one powder comprising a magnetic material.

[0036] In some embodiments, the non-magnetic and magnetic regions can be formed using at least one powder including one or more magnetic materials and one or more non-magnetic materials.

[0037] In some embodiments, the non-magnetic and magnetic regions can be formed using solid state materials.

[0038]

[0038] In some aspects, the method can include inserting an interface material between the magnetic and non-magnetic regions, the interface material preventing carbon migration during the three dimensional printing process.

[0039] In some aspects, the method can include forming a mechanical geometric joint at the boundary between the magnetic region and the non-magnetic region.

[0040]

[0040] In some aspects, a method of forming a retaining structure including magnetic and non-magnetic regions can include disposing one or more magnetic materials on one or more magnets of a rotor assembly. The method can include disposing one or more non-magnetic materials on one or more spacers. The spacers can be disposed between the one or more magnets. The method can include forming a cylindrical retaining structure sized to fit around the one or more magnetic materials and the one or more non-magnetic materials. The method can include forming the cylindrical retaining structure by a casting process.

[0041] In some aspects, a method of forming a retaining structure including magnetic and non-magnetic regions can include disposing one or more magnetic materials on one or more magnets of a rotor assembly. The method can include disposing one or more non-magnetic materials on one or more spacers. The spacers can be disposed between the one or more magnets. The method can include forming a cylindrical retaining structure sized to fit around the one or more magnetic materials and the one or more non-magnetic materials. The method can include forming a plurality of spokes between the non-magnetic region of the cylindrical retaining structure and a central hub.

[0042] In some aspects, the retaining structure includes a shaped pole formed as a composite structure.

[0043]

[0043] Many advantages are achieved by the present disclosure over the prior art. For example, embodiments of the present disclosure may provide a method and system for retaining magnets to a rotor assembly. These and other embodiments of the present disclosure, along with many of its advantages and features, are described in more detail in the following text and corresponding figures. [Brief description of the drawings]

[0044] [Figure 1] 1 illustrates a side view of a machine incorporating an exemplary retention structure according to one embodiment of the present invention; [Figure 2A] 1 shows a cross-section of a machine incorporating a non-magnetic retaining hoop. [Figure 2B] 1 shows a cross-sectional view of a machine incorporating a multi-metallic retaining hoop. [Diagram 3] 1 shows a first flux diagram illustrating magnetic flux leakage through a complete magnetic hoop. [Figure 4] 1 shows a second flux diagram for a machine including a multi-metallic retaining hoop having non-magnetic portions between the magnets. [Diagram 5]5 shows a third flux diagram for the same machine as in FIG. 4, except that the magnet retaining structure has been replaced with air between the magnets. [Figure 6] 1 illustrates a perspective view of a machine incorporating an exemplary retention structure according to one embodiment of the present invention; [Figure 7] 1 illustrates a side view of a first embodiment of an exemplary retention structure in accordance with an embodiment of the present invention. [Figure 8] 1 illustrates a side view of a portion of a first embodiment of an exemplary retention structure in accordance with an embodiment of the present invention. [Figure 9] 1 illustrates a side view of a second embodiment of an exemplary retention structure in accordance with an embodiment of the present invention. [Figure 10] 13 illustrates a side view of a portion of a second embodiment of an exemplary retention structure in accordance with an embodiment of the present invention. [Figure 11] 13 illustrates a side view of a third embodiment of an exemplary retaining structure in accordance with an embodiment of the present invention. [Figure 12] 13 illustrates a side view of a portion of a third embodiment of an exemplary retention structure in accordance with an embodiment of the present invention. [Figure 13] 1 shows a first exemplary diagram of a material locking mechanism at a material bond line. [Figure 14] FIG. 13 shows a second exemplary diagram of a structural reinforcement mechanism at a material bond line. [Figure 15] 2 shows a flow chart of a process for fabricating a multi-metal retention structure according to one embodiment of the present invention. [Figure 16] 4 is a flow chart of an exemplary process for manufacturing a retention structure in accordance with one embodiment of the present invention. [Figure 17] 5 is a flow chart of an exemplary process for manufacturing a retention structure according to another embodiment of the present invention. [Figure 18] 4 is a flow chart of an exemplary process for manufacturing a retention structure in accordance with certain embodiments of the present invention. [Figure 19] 1 illustrates a particular embodiment of a retention structure having multiple spokes. [Figure 20]5 is a flow chart of an exemplary process for manufacturing a retention structure in accordance with another specific embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045]

[0065] The same references and symbols in the various drawings indicate the same elements according to a particular exemplary implementation. Furthermore, multiple instances of an element may be indicated by following the first and second instances of the element with a letter or a hyphen.

[0046]

[0066] FIG. 1 illustrates a cross-sectional view of a machine 100 incorporating an exemplary retention structure 102 according to one embodiment of the present invention. FIG. 1 illustrates a retention structure 102 for a rotor assembly 104 that surrounds a plurality of magnets 106. The plurality of magnets 106 may be permanent magnets. Although four magnets 106 are illustrated in FIG. 1, the disclosure is not so limited and any number of magnets 106 may be used depending on the requirements of the machine and various design constraints. The rotor assembly 104 may be connected to a shaft 110 and may be configured to be inside a stator assembly 118 of the machine 100. The stator assembly 118 may include a plurality of magnets (e.g., electromagnets) that surround the rotor assembly 104 to generate a magnetic field that interacts with the magnetic field of the magnets 106 of the rotor assembly 104.

[0047]

[0067] Machine 100 may include a physical gap 122, also referred to as a mechanical gap. Physical gap 122 may be formed by a space between an outer surface of retention structure 102 and an inner surface of stator assembly 118. Physical gap 122 may be designed to meet certain system tolerances and to account for vibrations of rotor assembly 104. In various embodiments, physical gap 122 allows for airflow through machine 100 but does not interfere with orientation deviations of rotor assembly 104.

[0048]

[0068] The machine 100 may include a magnetic air gap 124. The magnetic air gap 124 is the distance between the outer surface of the magnet 106 and the inner surface of the stator assembly 118, passing through a material of the retaining structure 102 having a magnetic permeability of 1 (e.g., air, fiberglass, carbon fiber, or a non-magnetic material). Magnetic flux 126 passes from the magnet 106, through the retaining structure 102, through the physical air gap 122, and to the stator assembly 118. As the magnetic air gap 124 increases, the magnetic flux 126 reaching the stator assembly 118 decreases, thereby reducing the power and torque capabilities of the machine 100. Thus, in machines with an increased magnetic air gap 124, the size of the magnet 106 is typically increased to maintain the power or torque level of the machine 100. As the magnetic air gap 124 decreases, the magnetic flux 126 reaching the stator assembly 118 increases, and conversely, the magnetic flux 126 reaching the stator assembly 118 increases.

[0049]

[0069] In various machines that do not use the retention structure 102, an adhesive (e.g., glue) may be used to attach the magnets 106 to the rotor assembly 104. However, using adhesive alone generally makes the machine unsatisfactory at high speeds of operation due to the forces exerted on the magnets during operation, which may adversely affect retention of the magnets to the rotor assembly.

[0050]

[0070] The retaining structure 102 can be manufactured using magnetic or non-magnetic materials. In various examples, the retaining structure 102 can be a magnetic material (e.g., steel, or other alloy) or a non-magnetic material (e.g., astroy, or a high nickel alloy (e.g., Inconel)). If the retaining structure 102 is manufactured using a non-magnetic material, the magnetic air gap 124 is typically increased, which results in a reduction in the power and / or torque capabilities of the machine 100.

[0051]

[0071] If the retaining structure 102 is magnetic in the area above the spacers 112 (e.g., the entire retaining structure 102 is magnetic), then the magnetic flux 126 from one magnet 106 may leak across the retaining structure 102 to an adjacent magnet 106. Such leakage across the magnetic retaining structure 102 does not have any electromagnetic effect on the stator assembly 118. Thus, this leakage of magnetic flux 126 may reduce the amount of magnetic flux 126 that reaches the magnetic regions of the stator assembly 118, thereby reducing the power and / or torque capabilities of the machine 100.

[0052]

[0072] FIG 2A shows a cross-section of a conventionally designed machine incorporating a non-magnetic retaining hoop 202. FIG 2A shows magnets 206 held to the rotor by the non-magnetic retaining hoop 202. As the magnets 206 rotate through the magnetic field generated by the stator 218, magnetic flux lines 226 are generated. The magnetic field from the magnets 206 passes through the non-magnetic retaining hoop 202. FIG 2A shows a magnetic air gap 224 between the magnets 206 and the stator 218. As shown in FIG 2A, there is an air gap between the magnets 206.

[0053]

[0073] FIG. 2B shows a cross-sectional view of a machine incorporating a multi-metallic retaining hoop 212. FIG. 2B shows magnets 206 held to the rotor by the multi-metallic retaining hoop 212. As the magnets 206 rotate through the magnetic field generated by the stator 218, magnetic flux lines 226 are generated. As shown in FIG. 2B, there is an air gap 230 between the magnets 206. The magnetic field from the magnets 206 passes through the multi-metallic retaining hoop 212. FIG. 2B shows the magnetic air gap 224 between the multi-metallic retaining hoop 212 and the stator 218. In FIG. 2B, the magnetic air gap 224 has been reduced compared to the conventional design shown in FIG. 2A. In FIG. 2A, the magnetic air gap 224 begins at the outer surface of the magnets 206. In FIG. 2B, the magnetic air gap 224 begins at the outer edge of the multi-metallic retaining hoop 212. The reduction in the magnetic air gap 224 has increased the strength of the magnetic flux lines 226. Increasing the strength of the magnetic flux lines 226 can increase the power output of the machine.

[0054]

[0074] FIG. 3 shows a diagram of a first magnetic flux diagram 300 of a machine configured to generate a magnetic field as magnets 304 are held by a metal hoop holding structure 308 having magnetic portions between the magnets 304. The metal hoop holding structure 308 can be contracted over and around the magnets 304 (e.g., similar to a rubber band around the outside of some articles). Magnetic flux lines 326 are generated as the magnets 304 pass through the magnetic field generated by the stator assembly 312. FIG. 3 shows an air gap 306 between the metal hoop holding structure 308 and the stator assembly 312. As shown in FIG. 3, the magnetic flux lines 326 indicate leakage flux between the magnets 304, reducing the overall strength of the magnetic flux lines 326 generated by the machine. Magnetic flux leakage may reduce the amount of magnetic flux reaching the magnetic regions of the stator assembly 312, thereby reducing the power and / or torque capabilities of the machine.

[0055]

[0075] FIG. 4 shows a diagram of a second magnetic flux diagram 400 of a machine configured to generate a magnetic field as magnets 404 are held by a metallic hoop holding structure 408 having non-metallic portions between the magnets. The metallic hoop holding structure 408 can be contracted over and around the magnets 404. Magnetic flux lines 426 are generated as the magnets 404 pass through the magnetic field generated by the stator assembly 412. FIG. 4 shows an air gap 406 between the metallic hoop holding structure 408 and the stator assembly 412. As shown in FIG. 4, the magnetic flux no longer circulates across the holding structure 402 but instead crosses the air gap 406, coupling the magnetic flux with the stator assembly 412, thereby increasing the power output capability of the machine.

[0056]

[0076] FIG. 5 shows a diagram of a second magnetic flux diagram 500 of a machine configured to generate a magnetic field as magnets 504 held by a metal hoop holding structure 508 with air between the magnets. FIG. 5 shows that the multi-metallic hoop appears to have the same or similar magnetic flux leakage characteristics as simply air. The metal hoop holding structure 508 is connected to a rotor hub 510. Magnetic flux lines 526 are generated as the magnets 504 pass through the magnetic field generated by the stator assembly 512. FIG. 5 shows an air gap 506 between the metal hoop holding structure 508 and the stator assembly 512. As shown in FIG. 5, the magnetic flux no longer circulates across the holding structure 502 as shown in FIG. 3, but instead crosses the air gap 506, coupling the magnetic flux with the stator assembly 512, thereby increasing the power output capability of the machine.

[0057]

[0077] FIG. 6 illustrates a perspective view of a machine 600 incorporating an exemplary retaining structure 602 according to an embodiment of the present invention. In various embodiments, the machine may be an electric motor. The retaining structure 602 may be configured to mate with a rotor assembly 604 of the machine 600. The rotor assembly 604 may include a plurality of magnets 606. The rotor assembly 604 may include a pole retaining structure 608 to which the plurality of magnets 606 may be attached. The pole retaining structure 608 may be connected to a shaft 610. The magnets 606 may be distributed on a surface of the pole retaining structure 608. Areas 612 may be empty or filled with a non-magnetic material and may exist between adjacent magnets 606.

[0058]

[0078] The retaining structure 602 may include magnetic regions 614 and non-magnetic regions 616. The retaining structure 602 may be made using two or more different materials (e.g., one magnetic material and one non-magnetic material). The two or more different materials may be formed as a homogenous structure. The retaining structure 602 may be formed as a ring having one or more magnetic regions 614 tangentially alternating with one or more non-magnetic regions 616 configured to surround and retain the plurality of magnets 606 of the rotor assembly 604. The one or more magnetic regions 614 may be aligned with each of the plurality of magnets 606. The one or more non-magnetic regions 616 may be aligned with one or more areas 612 between the plurality of magnets 606 on the rotor assembly 604. The magnetic material may allow magnetic flux from the permanent magnets 606 to flow to the stator 620 in the stator structure 620. The non-magnetic regions 616 may reduce leakage of magnetic flux to adjacent permanent magnets 606 by using the non-magnetic material. The retaining structure 602 can be constructed using a variety of materials, including materials cast using a hot isostatic pressing (HIP) process, composite materials (e.g., carbon fiber or fiberglass materials), metal (e.g., steel or other alloy) cylinders, non-magnetic cylinders, or other materials.

[0059]

[0079] The magnetic region may comprise a ferromagnetic powder metal, also referred to as a permeable or magnetic material. The ferromagnetic powder material may be a soft ferromagnetic powder metal. In one embodiment of the invention, the ferromagnetic powder metal comprises nickel, iron, cobalt, or alloys thereof.

[0060]

[0080] In certain embodiments of the present invention, the non-ferromagnetic powder metal is an austenitic stainless steel, such as SS316. Generally, AISI 300 series stainless steels are non-magnetic and may be used in embodiments of the present invention. Also, AISI 8000 series steels are non-magnetic and may be used. Those skilled in the art will recognize many variations, modifications, and alternatives.

[0061]

[0081] In various embodiments, the retaining structure 602 can form a cylindrical hoop that can reduce magnetic flux leakage across the one or more non-magnetic regions 616 while providing a continuous magnetic gap 124, as shown in FIG. 1, between the plurality of magnets 606 and the one or more magnetic regions 614 of the stator assembly 618. In various embodiments, the one or more magnetic regions 614 and the one or more non-magnetic regions 616 can form a stave of the retaining structure 602.

[0062]

[0082] In addition to retaining the multiple magnets 606 in the magnetic pole retaining structure 608 against the radial and tangential forces generated by the rotating rotor assembly 604, the retaining structure 602 can be sized to provide a preload force to the multiple magnets 606 of the rotor assembly 604.

[0063]

[0083] FIG. 7 illustrates a side view of a first embodiment of an exemplary first retaining structure 700 according to an embodiment of the present invention. The first retaining structure 700 can include alternating magnetic regions 702 and non-magnetic regions 704. The first retaining structure 700 can be a continuous structure. It is noted that the number of magnetic regions 702 and non-magnetic regions 704 is merely exemplary and not limiting. The first retaining structure 700 does not require magnetic saturation of any portion of the structure and does not consume a magnetic air gap. In various embodiments, the first retaining structure 700 can have cylindrical inner and outer surfaces.

[0064]

[0084] FIG. 8 illustrates a side view of a portion 800 of a first embodiment of an exemplary retention structure according to an embodiment of the present invention. In various embodiments, the retention structure can be constructed of two different materials. For example, a first material 802 can have magnetic properties and a second material 804 can have non-magnetic properties. In various embodiments, the first material 802 can be made of a suitable magnetic material, including but not limited to magnetic steel, and the second material 804 can be made of a suitable non-magnetic material, including but not limited to astroy or inconel. A bond line 806 can be present between the first material 802 (e.g., a magnetic material) and the second material 804 (e.g., a non-magnetic material).

[0065]

[0085] 9 illustrates a side view of one embodiment of a second exemplary retention structure 900 in accordance with one embodiment of the present invention. In various embodiments, the retention structure 900 can be constructed from two different materials. For example, a first material 902 can have magnetic properties and a second material 904 can have non-magnetic properties. As shown in FIG. 9, the first material 902 can have a flat inner surface 908. The flat inner surface 908 allows for retention of a rectangular magnet.

[0066]

[0086] FIG. 10 illustrates a side view of a portion 1000 of a second embodiment of an exemplary retention structure according to an embodiment of the present invention. In various embodiments, the retention structure can be constructed of two different materials. For example, a first material 1002 can have magnetic properties and a second material 1004 can have non-magnetic properties. In various embodiments, the first material 1002 can include, but is not limited to, magnetic steel and the non-magnetic material can include, but is not limited to, astroy or inconel. A bond line 1006 can exist between the first material 1002 (e.g., a magnetic material) and the second material 1004 (e.g., a non-magnetic material). As shown in FIG. 10, the first material 1002 can have a flat inner surface 1008. The flat inner surface 1008 allows for retention of a rectangular magnet.

[0067]

[0087] FIG. 11 illustrates a side view of a third embodiment of an exemplary retention structure according to an embodiment of the present invention. In various embodiments, the retention structure 1100 can be formed using two different materials. For example, a first material 1102 can have magnetic properties and a second material 1104 can have non-magnetic properties. As shown in FIG. 11, the first material 1102 can have a flat inner surface 1108. The flat inner surface 1108 allows for the retention of rectangular magnets. Rectangular magnets are often less expensive than curved or shaped magnets. As shown in FIG. 11, the first material 1102 can be shaped. For example, in various embodiments, the first material 1102 can be formed with a crowned outer surface to change the shape of the magnetic flux lines and couple with the stator.

[0068]

[0088] FIG. 12 illustrates a side view of a portion of a third embodiment of an exemplary retention structure according to an embodiment of the present invention. In various embodiments, the retention structure 1200 can be formed using two different materials. For example, the first material 1202 can have magnetic properties and the second material 1204 can have non-magnetic properties. In various embodiments, the first material 1202 can include, but is not limited to, magnetic steel and the non-magnetic material can include, but is not limited to, astroy or inconel. A bond line 1206 can be present between the first material 1202 and the second material 1204. As shown in FIG. 12, the first material 1202 can have a flat inner surface 1208. The flat inner surface 1208 allows for retention of a rectangular magnet. As shown in FIG. 12, the first material 1202 can be shaped. For example, in various embodiments, the first material 1202 can be formed with a crowned outer surface to shape the magnetic flux lines generated by the magnet.

[0069]

[0089] In various embodiments, the retention structures can be welded together. However, welding is a disadvantage for high speed applications (e.g., for rotor assemblies) due to the possibility of the weld cracking or the components coming loose. In various embodiments, the structures can be composite structures. In other embodiments, the structures can be formed using a three-dimensional (3D) printing process. In various embodiments, the structures can be 3D printed and then subjected to a HIP process.

[0070]

[0090] FIG. 13 shows a joint 1300 between two dissimilar metals in a hot isostatic press bond. FIG. 13 is an exemplary 100x zoom of a cross section of a hot isostatic press bond. Hot isostatic pressing (HIP) is a material processing method in which materials are compressed by simultaneously applying high temperatures, from several hundred to over 2000°C, and isostatic pressures, from several tens to 200 MPa. Argon can be used as the pressure medium. Metal powders can also be turned into a packed solid by this method to process castings, with the inert gas applied at 7,350 psi (50.7 MPa) to 45,000 psi (310 MPa), but 15,000 psi (100 MPa) or higher is most common. The soaking temperature of the process can range from 900°F (482°C) for aluminum castings to 2,400°F (1,320°C) for nickel-based superalloys. When castings are processed with HIP, the simultaneous application of heat and pressure removes internal voids and microporosity through a combination of plastic deformation, creep, and diffusion bonding. This process improves the fatigue resistance of the part. Primary applications are the reduction of microshrinkage and strengthening of powder metals, ceramic composites, and metal clads. Hot isostatic pressing can also be used as part of the sintering (powder metallurgy) process and for the production of metal matrix composites, and is often used as a post-process in additive manufacturing.

[0071]

[0091] A first material 1302 can be bonded to a second material 1304. In various embodiments, a portion of the first material 1302 can be introduced into a portion of the second material 1304. FIG. 13 shows an example geometry of an extension of the first material 1302 that extends into and is at least partially surrounded by the second material 1304. This type of geometry can enhance the bond between the first material 1302 and the second material 1304. Other geometries, such as a rectangular cross section, can be used. Introducing a feature at the bond line changes how the two materials interact with the bond line. The protruding feature absorbs bending stresses due to mismatch in the strain rates of the materials. The feature does not need to be locked.

[0072]

[0092] The electrically conductive material can form tabs that can be inserted into a blank, which can be similar to the tabs and blanks of a jigsaw puzzle. This tab / blank bond can provide increased strength between dissimilar materials.

[0073]

[0093] FIG. 14 shows a second exemplary diagram of structural reinforcement features at a material interface 1400. FIG. 14 shows the reinforcement of material features at the bond line. A first material 1402 can be joined to a second material 1404 using a third material 1406 at the bond line. In one example, the first material 1402 can be a non-magnetic material. The second material 1404 can be a magnetic material. The third material 1406 can be a different material than the first material 1402 and the second material 1404. The third material can stop carbide precipitation across the bond line. This strengthens the structural bond at the bond line. The tangential discontinuous permeability can reduce magnetic flux leakage.

[0074]

[0094] FIG. 15 shows a flow chart of a process for manufacturing a multi-metallic retained structure using hot isostatic pressing (HIP), according to an embodiment of the present invention. HIP is a manufacturing process used to reduce the porosity of metals and increase the density of many ceramic materials. This improves the mechanical properties and workability of the material. HIP is a process that uses high pressure and high temperature for a set time to improve material properties. The HIP process can form a composite structure in which two or more dissimilar materials can be bonded together. The HIP process can control the parameters (e.g., temperature and pressure) to produce desired material properties in the composite structure. In an exemplary process, a furnace located within a pressure vessel is pressurized with argon. The uniform pressure and high temperature allow for drying and removal of any product defects while improving mechanical properties. In addition to removing defects, this process can also be used to layer materials together or solidify powders into a solid form, resulting in an improved product over those obtained with traditional methods.

[0075]

[0095] The HIP process uses metal powders (e.g., nickel, chromium, cobalt, and iron) that can be fabricated into structures having uniform composition and dense microstructures with improved toughness, strength, fracture resistance, and thermal expansion coefficient. Such improved properties can be particularly beneficial in the manufacture of rotating components for turbines, for example, where high temperature and / or high stress conditions exist.

[0076]

[0096] Typically, the metal powder is placed in a sealed container (sometimes called a "can"), the contents of which may be placed under vacuum. The container is also subjected to high temperatures and externally pressurized, for example using an inert gas such as argon, to avoid chemical reactions. Hot isostatic pressing cycles use temperatures of up to and exceeding 1200°C and pressures of up to and exceeding 150 MPa. By pressurizing the container enclosing the powder, the selected fluid medium (e.g., inert gas) exerts pressure on the powder on all sides and in all directions.

[0077]

[0097] Figure 15 is a flow chart of an exemplary process 1500 for manufacturing a support structure according to one embodiment of the present invention. In some implementations, one or more process blocks of Figure 15 may be performed by a HIP manufacturing system. In some implementations, one or more process blocks of Figure 15 may be performed by another piece of equipment or a group of equipment separate from or including the HIP manufacturing system.

[0078]

[0098] The method can include providing a mold to receive at least one powder for compaction (1510). The powder can include either magnetic and non-magnetic materials or some combination thereof. The magnetic materials can include various metals or metal alloys. The mold can be shaped to produce a cylindrical structure.

[0079]

[0099] The mold may include a top, a bottom, and an outer wall. In an exemplary embodiment, the mold may be constructed of conventional materials such as austenitic stainless steel, such as 304SS. The top, bottom, and outer wall may be constructed as a single piece. However, the mold may also include other structures, including structures in which the top, bottom, and outer wall are created as one or more separate pieces. Sliding cores, ejectors, and other moving parts may be incorporated into the mold to form different material regions of the composite sleeve, as needed.

[0080]

[0100] The method can include determining 1520 a position of a shape-controlling element along at least one wall of the mold. The shape-controlling element can be positioned to control deformation of the mold during hot isostatic pressing.

[0081]

[0101] The mold can also include one or more diffusion barriers. Diffusion barriers can be used to separate the various powders from each other or from the top, bottom, or outer walls of the mold. Diffusion barriers function to prevent diffusion and are placed as layers or inner liners on the mold that are located between the various powder metals and the mold itself. Diffusion barriers can prevent or minimize the transfer of elements from the various powder layers, or between the powders and the mold, or from the mold to the powders.

[0082]

[0102] The diffusion barrier may be composed of one or more materials specifically selected to prevent the diffusion process. Depending on the composition of the powder, the mold, and the conditions of the HIP process, various materials may be used. For example, the diffusion barrier may be composed of various metal nitrides, sulfides, carbides, carbonitrides, or metal oxides. Ceramic materials may also be used. In certain applications, the diffusion barrier may be composed exclusively of metals, for example tantalum, gold, silver, or copper. Other materials may be applied as well.

[0083]

[0103] Various techniques can be used to place the diffusion barrier along the inside of the mold. The diffusion barrier can be composed of, for example, a metal foil placed along the inside of the mold. The foil can be specially configured according to the geometry of the mold, or can be applied as overlapping sheets prior to placing the powder in the mold or between various layers of powder. For example, a diffusion layer can be placed between a metallic layer and a non-metallic layer. Various plating techniques can also be used to deposit the diffusion barrier inside the mold. For example, electroplating or electroless plating can be used to deposit a desired thickness of barrier material as a layer on the mold. Chemical vapor deposition can also be used to deposit a desired thickness of material on the mold to create the diffusion barrier. Ceramic coatings can also be applied by various techniques, including plasma spraying. Using the teachings disclosed herein, one skilled in the art will understand that various other methods can also be used to apply the diffusion barrier.

[0084]

[0104] In various embodiments, the process 1500 can include inserting an interface material between the magnetic and non-magnetic regions. The interface material can inhibit carbon migration during hot isostatic pressing.

[0085]

[0105] In various embodiments, the process 1500 can include forming a mechanical geometric joint at the boundary between the magnetic and non-magnetic regions.

[0086]

[0106] In various embodiments, the diffusion barrier can be used to shape the magnetic and non-magnetic regions of the retention structure. For example, the magnetic regions can be shaped to improve magnetic flux to the stator assembly. In various embodiments, the magnetic regions can be formed in the shape of a crown.

[0087]

[0107] By shaping the metal areas of the retaining structure, it is possible to shape the magnetic flux of the magnetic poles resulting in a more sinusoidal electric machine with less torque ripple, which can provide better output quality with less noise.

[0088]

[0108] In various embodiments, a divider sheet (e.g., a plastic material) can be used to separate the various materials in the structure. Prior to the HIP process, the divider sheet can be removed so that the different materials come into contact but do not mix.

[0089]

[0109] In various embodiments, portions of the structure may be formed from solid metal, while various other materials are formed into the solid metal during the HIP process. In various embodiments, the magnetic regions may be formed using a solid material, and the non-magnetic regions may be formed using one or more powders comprising a non-magnetic material. In various embodiments, the non-magnetic regions may be formed using a solid material, and the magnetic regions may be formed using one or more powders comprising a magnetic material. In various embodiments, the non-magnetic regions and the magnetic regions may be formed using powders including magnetic and non-magnetic materials. In various embodiments, the non-magnetic regions and the magnetic regions may be formed using a solid material.

[0090]

[0110] The method can include disposing (1530) shape-controlling elements along one or more walls of the mold. Various shape-controlling elements can shape the retention structure to fit around the rotor assembly. In various embodiments, the shape-controlling elements can be used to shape the exterior of the retention structure. In various embodiments, the exterior structure can have a smooth continuous exterior to reduce vibration. In various embodiments, the interior surface can be shaped to accommodate a rectangular magnet.

[0091]

[0111] The method can include deforming the mold while compressing the powder during the hot isostatic press to provide a cylindrical hoop structure (1540). The mold can be placed in a pressure vessel that is evacuated and filled with an inert gas, such as argon, during the HIP process.

[0092]

[0112] Process 1500 may include additional implementations, such as any single implementation or any combination of implementations associated with one or more other processes described below and / or elsewhere herein. It should be understood that the specific steps illustrated in FIG. 15 provide techniques for manufacturing a retention structure according to various embodiments of the present disclosure. Alternative embodiments may perform other sequences of steps. For example, alternative embodiments of the present disclosure may perform the steps outlined above in a different order. Additionally, individual steps illustrated in FIG. 15 may include multiple sub-steps that may be performed in various orders as appropriate for the individual steps. Additionally, additional steps may be added or removed depending on the application. Those skilled in the art will recognize numerous variations, modifications, and alternatives.

[0093]

[0113] FIG. 16 is a flow chart of an exemplary process 1600 for manufacturing a retention structure according to one embodiment of the present invention. The retention structure can include magnetic and non-magnetic regions. In some implementations, one or more process blocks of FIG. 16 can be performed by a welding system. In some implementations, one or more process blocks of FIG. 16 can be performed by another device or group of devices separate from or including the welding system.

[0094]

[0114] The method may include disposing 1610 one or more magnetic materials on one or more magnets of the rotor assembly, which may be accomplished using a rack that holds the magnetic and non-magnetic materials in place relative to one another.

[0095]

[0115] The method may include disposing one or more non-magnetic materials on one or more spacers, the spacers being disposed between the one or more magnets 1620. This disposing may be accomplished using a rack that holds the magnetic and non-magnetic materials in place relative to one another.

[0096]

[0116] The method may include welding 1630 an edge of the one or more magnetic materials to an edge of the one or more non-magnetic materials to form a cylindrical retention structure sized to fit around one or more magnets of the rotor assembly. The welding may include MIG-Gas Metal Arc Welding (GMAW), TIG-Gas Tungsten Arc Welding (GTAW), Stick-Shielded Metal Arc Welding (SMAW), and Flux Cored-Flux Cored Arc Welding (FCAW).

[0097]

[0117] Process 1600 may include additional implementations, such as any single implementation or any combination of implementations associated with one or more other processes described below and / or elsewhere herein. It should be understood that the specific steps illustrated in FIG. 16 provide techniques for manufacturing a retention structure according to various embodiments of the present disclosure. Alternative embodiments may perform other sequences of steps. For example, alternative embodiments of the present disclosure may perform the steps outlined above in a different order. Additionally, individual steps illustrated in FIG. 16 may include multiple sub-steps that may be performed in various orders as appropriate for the individual steps. Additionally, additional steps may be added or removed depending on the application. Those skilled in the art will recognize numerous variations, modifications, and alternatives.

[0098]

[0118] FIG. 17 is a flow chart of an exemplary process 1700 for manufacturing a retention structure according to another embodiment of the present invention. The retention structure can include magnetic and non-magnetic regions. In some implementations, one or more process blocks of FIG. 17 can be performed by a three-dimensional (3D) printer. In some implementations, one or more process blocks of FIG. 17 can be performed by another device or group of devices separate from or including the 3D printer.

[0099]

[0119] The method may include disposing 1710 one or more magnetic materials on one or more magnets of the rotor assembly, which may be accomplished using a rack that holds the magnetic and non-magnetic materials in place relative to one another.

[0100]

[0120] The method may include disposing one or more non-magnetic materials on one or more spacers, the spacers being disposed between the one or more magnets 1720. This disposing may be accomplished using a rack that holds the magnetic and non-magnetic materials in place relative to one another.

[0101]

[0121] The method can include forming a cylindrical retaining structure sized to fit around the one or more magnetic materials and the one or more non-magnetic materials, where forming the cylindrical retaining structure is by a three dimensional printing process (1730).

[0102]

[0122] Process 1700 may include additional implementations, such as any single implementation or any combination of implementations associated with one or more other processes described below and / or elsewhere herein. It should be understood that the specific steps illustrated in FIG. 17 provide techniques for manufacturing a retention structure according to various embodiments of the present disclosure. Alternative embodiments may perform other sequences of steps. For example, alternative embodiments of the present disclosure may perform the steps outlined above in a different order. Additionally, individual steps illustrated in FIG. 17 may include multiple sub-steps that may be performed in various orders as appropriate for the individual steps. Additionally, additional steps may be added or removed depending on the application. Those skilled in the art will recognize numerous variations, modifications, and alternatives.

[0103]

[0123] 18 is a flow chart of an exemplary process 1800 for manufacturing a retention structure, according to certain embodiments of the present invention. The retention structure can include magnetic and non-magnetic regions. In some implementations, one or more process blocks of FIG. 18 can be performed by a casting process. In some implementations, one or more process blocks of FIG. 18 can be performed by another device or group of devices separate from or including casting.

[0104]

[0124] The method may include disposing 1810 one or more magnetic materials on one or more magnets of the rotor assembly, which may be accomplished using a rack that holds the magnetic and non-magnetic materials in place relative to one another.

[0105]

[0125] The method may include disposing one or more non-magnetic materials on one or more spacers, the spacers being disposed between the one or more magnets 1820. This disposing may be accomplished using a rack that holds the magnetic and non-magnetic materials in place relative to one another.

[0106]

[0126] The method can include forming a cylindrical retaining structure sized to fit around one or more magnetic materials and one or more non-magnetic materials, where the forming of the cylindrical retaining structure is by a casting process (1830). Casting is a manufacturing process in which a liquid material is poured into a mold that typically contains a hollow cavity of a desired shape and then solidified. The solidified part is also known as a casting and is ejected or broken from the mold to complete the process. Casting materials are typically metals or various time-setting materials that harden after mixing two or more components together. Examples are epoxy resin, concrete, plaster, and clay. Casting is used quite often to make complex shapes that are difficult or uneconomical to make in other ways. Heavy equipment such as machine tool beds, ship propellers, etc. can be easily cast in the required size rather than manufactured by joining several small pieces together.

[0107]

[0127] Process 1800 may include additional implementations, such as any single implementation or any combination of implementations associated with one or more other processes described below and / or elsewhere herein. It should be understood that the specific steps illustrated in FIG. 18 provide techniques for manufacturing a retention structure according to various embodiments of the present disclosure. Alternative embodiments may perform other sequences of steps. For example, alternative embodiments of the present disclosure may perform the steps outlined above in a different order. Additionally, individual steps illustrated in FIG. 18 may include multiple sub-steps that may be performed in various orders as appropriate for the individual steps. Additionally, additional steps may be added or removed depending on the application. Those skilled in the art will recognize numerous variations, modifications, and alternatives.

[0108]

[0128] 19 shows a side view of an example retention structure 1902 of a rotor assembly 1900 for retaining a plurality of magnets 1906. The retention structure 1902 may include a magnetic region 1914 on the magnets 1906 attached to the pole retention structure 1908. The retention structure 1902 may also include a non-magnetic region 1916. The pole retention structure 1908 may be attached to a shaft 1910.

[0109]

[0129] In various embodiments, the retaining structure 1902 can include multiple spokes 1930. In FIG. 19, four spokes 1930 are shown, however, any number of spokes 1930 may be used. For example, FIG. 19 shows a spoke 1930 attached to each of the non-magnetic regions 1916. In various examples, a spoke 1930 may be attached to every other non-magnetic region 1916. In various alternative embodiments, multiple spokes 1930 can be attached to each non-magnetic region of the retaining structure 1902.

[0110]

[0130] The spokes 1930 can be manufactured (e.g., by a HIP process, casting, carbon fiber manufacturing, etc.) as part of the retaining structure 1902. In various embodiments, the spokes 1930 can be manufactured independent of the retaining structure 1902 and can be attached to the retaining structure 1902 by any conventional means (e.g., welding, adhesives, fasteners, etc.).

[0111]

[0131] The spokes 1930 may include a proximal end 1932 and a distal end 1934. The distal ends 1934 of the spokes 1930 may be affixed to the non-magnetic region 1916 of the retaining structure. The proximal ends 1932 of the spokes 1930 may be attached to a central hub 1936. The central hub 1936 may be manufactured as part of the retaining structure 1902 (e.g., by a HIP process, casting, carbon fiber manufacturing, etc.). In various embodiments, the central hub 1936 may be manufactured independent of the retaining structure 1902 and may be attached to the spokes 1930 by any conventional means (e.g., welding, gluing, fasteners, etc.). In various embodiments, the spokes 1930 may be attached directly to the shaft 1910, thereby eliminating the central hub 1936.

[0112]

[0132] FIG. 20 is a flow chart of an exemplary process 2000 for manufacturing a retention structure according to another specific embodiment of the present invention. The retention structure can include magnetic and non-magnetic regions. In some implementations, one or more process blocks of FIG. 20 can be performed by a casting process. In some implementations, one or more process blocks of FIG. 20 can be performed by another device or group of devices separate from or including the casting.

[0113]

[0133] The method may include disposing one or more magnetic materials on one or more magnets of the rotor assembly (2010). This disposing may be accomplished using a rack that holds the magnetic and non-magnetic materials in place relative to one another.

[0114]

[0134] The method can include disposing one or more non-magnetic materials on one or more spacers, where the spacers are disposed between one or more magnets (2020). This disposing can be accomplished using a rack that holds the magnetic and non-magnetic materials in place relative to one another.

[0115]

[0135] The method may include forming a cylindrical retention structure (2030) sized to fit around the one or more magnetic materials and the one or more non-magnetic materials. In various embodiments, forming the cylindrical retention structure may be accomplished by a welding process. In various embodiments, forming the cylindrical retention structure may be accomplished by a 3D printing process. In various embodiments, forming the cylindrical retention structure may be accomplished by a casting process. In various embodiments, forming the cylindrical retention structure may be accomplished by one or more of extrusion, slip casting, press molding, tape casting, and injection molding. In various embodiments, forming the cylindrical retention structure may be accomplished by a carbon fiber manufacturing process.

[0116]

[0136] The method can include forming 2040 a plurality of spokes between the non-magnetic region of the cylindrical retention structure and a central hub, which can be accomplished by one or more of processes including welding, casting, extrusion, slip casting, press molding, tape casting and injection molding, and carbon fiber manufacturing processes.

[0117]

[0137] Process 2000 may include additional implementations, such as any single implementation or any combination of implementations associated with one or more other processes described below and / or elsewhere herein. It should be understood that the specific steps illustrated in FIG. 20 provide techniques for manufacturing a retention structure according to various embodiments of the present disclosure. Alternative embodiments may perform other sequences of steps. For example, alternative embodiments of the present disclosure may perform the steps outlined above in a different order. Additionally, individual steps illustrated in FIG. 20 may include multiple sub-steps that may be performed in various orders as appropriate for the individual steps. Additionally, additional steps may be added or removed depending on the application. Those skilled in the art will recognize numerous variations, modifications, and alternatives.

[0118]

[0138] The methods, systems, and devices described above are examples. Various configurations may omit, substitute, or add various procedures or components as appropriate. For example, in alternative configurations, the methods may be performed in an order different from that described, and / or various steps may be added, omitted, and / or combined. Also, features described with respect to particular configurations may be combined in various other configurations. Different aspects and elements of the configurations may be combined in a similar manner. Also, technology evolves, and thus many of the elements are examples and are not intended to limit the scope of the disclosure or claims.

[0119]

[0139] Specific details are described in the description to provide a thorough understanding of the exemplary configurations (including implementations). However, the configurations can be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques are shown without unnecessary detail to avoid obscuring the configurations. This description provides only exemplary configurations and does not limit the scope, applicability, or configurations of the claims. Rather, the foregoing description of the configurations provides those skilled in the art with an enabling description to implement the described techniques. Various changes can be made in the function and arrangement of elements without departing from the spirit or scope of the present disclosure.

[0120]

[0140] Also, the configurations may be described as processes that are shown as flow diagrams or block diagrams. Although each operation may be described as a sequential process, many of the operations may be performed in parallel or simultaneously. Also, the order of operations may be rearranged. A process may have additional steps not included in the diagrams. Furthermore, the example methods may be realized by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. If implemented in software, firmware, middleware, or microcode, the program code or code segments to perform the necessary tasks may be stored in a non-transitory computer-readable medium, such as a storage medium. A processor may perform the tasks described.

[0121]

[0141] While several example configurations have been described, various modifications, alternative configurations, and equivalents may be used without departing from the spirit of the disclosure. For example, the above elements may be components of a larger system, and other rules may take precedence over or otherwise modify the application of the disclosure. Also, some steps may be taken before, during, or after considering the above elements.

Claims

1. A rotor, a plurality of permanent magnets arranged around the rotor; a plurality of sections separating each of the plurality of permanent magnets; a cylindrical hoop configured to hold the plurality of permanent magnets to the rotor, a plurality of non-magnetic regions, each of the plurality of non-magnetic regions being aligned with a corresponding one of the plurality of regions; a cylindrical hoop including a plurality of magnetic regions, each of the plurality of magnetic regions aligned with a corresponding one of the plurality of permanent magnets, alternating tangentially with each of the plurality of non-magnetic regions, and joined to an adjacent non-magnetic region at a joining interface including a portion of each magnetic region extending into the adjacent non-magnetic region; A structure comprising:

2. Further comprising a stator surrounding the structure and having a second plurality of magnetic regions; 2. The structure of claim 1, wherein the cylindrical hoop reduces magnetic flux leakage across the plurality of non-magnetic regions while providing a continuous radial magnetic air gap between the plurality of permanent magnets disposed about the rotor and the second plurality of magnetic regions of the stator.

3. The structure described in claim 1, wherein the plurality of magnetic regions and the plurality of non-magnetic regions form the staves of the cylindrical hoop.

4. The structure of claim 1 , wherein the cylindrical hoop is sized to provide a preload force to the plurality of permanent magnets disposed about the rotor.

5. The structure described in claim 1, wherein the multiple magnetic regions are a combination of multiple materials forming different layers.

6. The structure described in claim 1, wherein the multiple non-magnetic regions are a combination of multiple materials forming different layers.

7. The structure of claim 1 , wherein each of the plurality of magnetic regions includes a crowned outer surface for shaping magnetic flux lines of the plurality of permanent magnets disposed about the rotor.

8. 2. The structure of claim 1, wherein the inner surface of the cylindrical hoop is non-circular and the plurality of permanent magnets arranged around the rotor are rectangular.

9. The structure of claim 1 wherein the outer surface of the cylindrical hoop is continuous.

10. Housing and a rotor assembly disposed within the housing and including a plurality of permanent magnets separated by a plurality of sections; a retaining sleeve disposed about the rotor assembly and configured to retain the plurality of permanent magnets to the rotor assembly, a plurality of non-magnetic regions, each of the plurality of non-magnetic regions being aligned with a corresponding one of the plurality of regions; a retaining sleeve including a plurality of magnetic regions, each of the plurality of magnetic regions aligned with a corresponding one of the plurality of permanent magnets, alternating tangentially with each of the plurality of non-magnetic regions, and joined to an adjacent non-magnetic region at a joining interface including a portion of each magnetic region extending into the adjacent non-magnetic region; a stator surrounding the rotor assembly and the retaining sleeve and having a second plurality of magnetic regions; An electric machine comprising:

11. An electric machine as described in claim 10, further comprising an air gap between the rotor assembly and the stator, wherein the retaining sleeve reduces magnetic flux leakage across the plurality of non-magnetic regions while providing a continuous radial magnetic gap between the plurality of permanent magnets and a second plurality of magnetic regions of the stator.

12. An electric machine as described in claim 10, wherein the plurality of magnetic regions and the plurality of non-magnetic regions form staves of the retaining sleeve.

13. An electric machine as described in claim 10, wherein the retaining sleeve is cylindrical and sized to provide a preload force to the plurality of permanent magnets of the rotor assembly.

14. An electric machine as described in claim 10, wherein the multiple magnetic regions are a combination of multiple materials forming different layers.

15. An electric machine as described in claim 10, wherein the multiple non-magnetic regions are a combination of multiple materials forming different layers.

16. The electric machine of claim 10 , wherein each of the plurality of magnetic regions includes a crowned outer surface for shaping magnetic flux lines of the plurality of permanent magnets disposed about the rotor.

17. An electric machine as described in claim 10, wherein the inner surface of the retaining sleeve is not circular and the plurality of permanent magnets are rectangular.

18. An electric machine as described in claim 10, wherein the outer surface of the retaining sleeve is continuous.

19. 1. A method of forming a support structure including magnetic and non-magnetic regions, comprising: providing a mold for receiving at least one powder for compaction, the at least one powder comprising either a magnetic material or a non-magnetic material; determining a position of a shape control element along at least one wall of the mold, the shape control element being configured to control deformation of the mold during hot isostatic pressing; positioning the shape control elements along one or more walls of the mold; deforming the mold while compressing the at least one powder in a hot isostatic press to form a cylindrical hoop structure; A method comprising:

20. 20. The method of claim 19, wherein the magnetic regions are formed using a solid material and the non-magnetic regions are formed using the at least one powder containing the non-magnetic material.

21. 20. The method of claim 19, wherein the non-magnetic regions are formed using a solid material and the magnetic regions are formed using the at least one powder that includes a magnetic material.

22. 20. The method of claim 19, wherein the non-magnetic regions and the magnetic regions are formed using the at least one powder including the magnetic material and the non-magnetic material.

23. The method of claim 19 , wherein the non-magnetic and magnetic regions are formed using a solid material.

24. 20. The method of claim 19, further comprising forming a mechanical geometric joint at the boundary between the magnetic region and the non-magnetic region.

25. 1. A method of forming a support structure including magnetic and non-magnetic regions, comprising: disposing one or more magnetic materials on one or more magnets of the rotor assembly; disposing one or more non-magnetic materials on one or more spacers, the spacers being disposed between the one or more magnets; welding an edge of the one or more magnetic materials to an edge of the one or more non-magnetic materials to form a cylindrical retention structure sized to fit around the one or more magnets of the rotor assembly; A method comprising:

26. 1. A method of forming a support structure including magnetic and non-magnetic regions, comprising: providing a rotor assembly including a shaft and a pole retaining structure; attaching a plurality of magnets to the pole-holding structure; disposing one or more magnetic materials on one or more magnets of the rotor assembly; disposing one or more non-magnetic materials on one or more spacers, the spacers being disposed between the one or more magnets; forming a cylindrical retention structure surrounding the plurality of magnets by a three-dimensional printing process, the cylindrical retention structure comprising: the magnetic regions including a magnetic material, each of the magnetic regions aligned with a corresponding magnet of the plurality of magnets; the non-magnetic regions including a non-magnetic material, each of the non-magnetic regions being aligned with a corresponding area between each of the plurality of magnets; A method comprising:

27. 27. The method of claim 26, wherein the magnetic regions are formed using a solid material and the non-magnetic regions are formed using one or more powders including the one or more non-magnetic materials.

28. 27. The method of claim 26, wherein the non-magnetic regions are formed using a solid material and the magnetic regions are formed using at least one powder containing a magnetic material.

29. 27. The method of claim 26, wherein the non-magnetic regions and the magnetic regions are formed using at least one powder including the one or more magnetic materials and the one or more non-magnetic materials.

30. 27. The method of claim 26, wherein the non-magnetic and magnetic regions are formed using a solid material.

31. 27. The method of claim 26, further comprising inserting an interface material between the magnetic region and the non-magnetic region, the interface material inhibiting carbon migration during the three dimensional printing process.

32. 27. The method of claim 26, further comprising forming a mechanical geometric joint at the boundary between the magnetic region and the non-magnetic region.

33. 1. A method of forming a support structure including magnetic and non-magnetic regions, comprising: disposing one or more magnetic materials on one or more magnets of the rotor assembly; disposing one or more non-magnetic materials on one or more spacers, the spacers being disposed between the one or more magnets; forming a cylindrical retention structure sized to fit around the one or more magnetic materials and the one or more non-magnetic materials, wherein forming the cylindrical retention structure is achieved by a casting process; A method comprising:

34. 1. A method of forming a support structure including magnetic and non-magnetic regions, comprising: disposing one or more magnetic materials on one or more magnets of the rotor assembly; disposing one or more non-magnetic materials on one or more spacers, the spacers being disposed between the one or more magnets; forming a cylindrical retention structure sized to fit around the one or more magnetic materials and the one or more non-magnetic materials; forming a plurality of spokes between the non-magnetic region of the cylindrical retaining structure and a central hub; A method comprising:

35. 35. The method of claim 34, wherein the one or more magnetic materials comprise shaped poles formed as a composite structure.

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