Field of the Invention The present invention relates to magnetic couplers, and more particularly to magnet couplers having increased electromagnetic torque.

Background of the Invention Industrial processes frequently use rotating machinery. The use of rotating machinery entails coupling a load to a motor. The connection between the load and the motor can be a direct physical connection, such as a clutch, a belt and pulley system, or in-line couplings. All of these direct connections require precise alignment of the motor shaft and the load shaft. This precise alignment can be achieved using techniques such as laser alignment. However, laser alignment is expensive and time consuming, and may be ineffective if either the motor shaft or the load shaft is out of round.

The use of flexible couplings allows a limited degree of misalignment between the motor shaft and the load shaft. However, a flexible coupling will wear and will eventually fail. This introduces additional costs and equipment downtime.

An alternative to a direct connection is an electromagnetic coupling. One example of an electromagnetic coupling is an eddy current coupling. An eddy current coupling couples the motor shaft and the load shaft by magnetic fields produced by

controlled DC currents. Thus, the motor shaft and load shaft are not physically connected. However, an eddy current coupling is expensive, complex, and may be inappropriate for heavy industrial applications.

Another type of electromagnetic coupling is a permanent magnet coupling. A permanent magnet coupling couples the motor shaft and the load shaft by magnetic fields produced by permanent magnets rather than by controlled DC currents. The permanent magnet coupler is simpler, less expensive, and better adapted to heavy industrial use than the eddy current coupler. However, the amount of electromagnetic torque that can be transferred between the motor shaft and the load shaft by known permanent magnet couplers is limited.

An increase in output loading, requiring additional electromagnetic torque, causes additional slip in permanent magnet couplers known in the art. As slip increases from zero, a maximum torque, known as "breakdown torque" is generated.

As slip increases past the slip at which breakdown torque is achieved, known as "breakdown slip," the generated torque decreases. This torque-slip relationship is shown in FIGURE 1. Breakdown torque is usually about twice the rated torque of the permanent magnet coupler. Breakdown torque is not ordinarily attained under normal, steady state operation, but may be developed under momentary transient overloads. It would be desirable to increase the slip at which breakdown torque occurs in permanent magnet couplers because a higher starting torque would be achieved. However, as slip increases in permanent magnet couplers, additional heat is generated in the conductors due to increased conductor losses. Increased conductor losses result in lowered operating efficiency, can cause warping of the conductor, and can ultimately lead to failure of the conductor. Thus, there is an unmet need in the art for a permanent magnet coupler having an increased breakdown slip and an increased starting torque.

The conductor assemblies used in conventional permanent magnet couplers are made from plates of a conductor, such as copper. The conductor plates must be machined. Similarly, permanent magnet assemblies used in conventional permanent magnet couplers are also machined. Machining is a complex and costly manufacturing process. In order to fabricate conductor assemblies and permanent magnet assemblies of various sizes, retooling is required. This retooling further increases the complexity and cost. Therefore, there is also an unmet need in the art for permanent magnet couplers having permanent magnet assemblies and conductor assemblies that do not have the above drawbacks imposed by machining.

Summarv of the Invention The present invention provides a magnet coupler having increased electromagnetic torque. The present invention accomplishes this by providing a coupler that includes a first shaft having a first axis and a second shaft that is separate from the first shaft. The second shaft has a second axis that is substantially aligned with the first axis. A first disk is arranged to rotate about the first shaft. An array of permanent magnet assemblies is mounted on the first disk. A second disk is arranged to rotate about the second shaft. A composite conductor assembly is mounted on the second disk. The permanent magnet assemblies and the conductor assembly are laterally spaced apart from each other, such that rotation of the first disk causes rotation of the second disk due to electromagnetic coupling between the permanent magnet assemblies and the conductor assembly.

According to one aspect, the composite conductor assembly includes a copper-semiconductor composite. The semiconductor is suitably silicon. The use of a copper-semiconductor composite for the conductor assembly raises the resistance of the conductor assembly and advantageously raises the slip at which breakdown torque occurs. The copper-semiconductor composite is able to withstand heat generated by the increased slip without resulting in warping or failure of the conductor assembly.

Another advantage resulting from the use of a copper-semiconductor conductor assembly is that starting torque for the coupler is also increased.

According to another aspect of the invention, the coupler further includes a ferrous backing mounted between the conductor assembly and the second disk. The ferrous backing is suitably an electrolytic iron composite. The use of an electrolytic iron composite backing increases inductance and compensates for additional conductor losses due to the use of the semiconductor in the conductor assembly.

The present invention increases electromagnetic torque even further over torque generated by permanent magnet couplers known in the art. The present invention accomplishes this by providing a moment arm that is greater than that in permanent magnet couplers currently known in the art. According to one embodiment of the present invention, a permanent magnet coupler includes a first shaft having a first axis. A second shaft is separate from the first shaft, and the second shaft has a second axis that is substantially aligned with the first axis. A first disk is arranged to rotate about the first shaft. An array of permanent magnet assemblies is mounted on the first disk, and the permanent magnet assemblies are located radially about the first disk at a first distance from the first axis. A second disk is arranged to

rotate about the second shaft. A composite conductor assembly is mounted on the second disk. The composite conductor assembly is located radially about the second disk at a second distance from the second axis that is less than the first distance. The permanent magnet assembly and the conductor assembly are laterally and radially spaced apart from each other, such that rotation of the first disk causes rotation of the second disk due to electromagnetic coupling between the permanent magnet assemblies and the conductor assembly.

The present invention increases the electromagnetic torque even further by providing an increased surface area of permanent magnets and an increased surface area of conductor for cutting through magnetic lines of flux. According to one aspect of the invention, the permanent magnet assemblies include first and second permanent magnets having first and second faces, and the composite conductor assembly includes first and second conductor segments that are arranged to face toward the first and second faces of the first and second permanent magnets The first and second permanent magnets are suitably arranged substantially normal to each other, and the first and second conductor segments are suitably arranged substantially normal to each other. According to another aspect of the present invention, the permanent magnet assemblies include a third permanent magnet having a third face, and the first, second, and third permanent magnets are arranged in substantially a U-configuration.

The conductor assembly includes a third conductor segment that is arranged to face the third permanent magnets.

According to another aspect of the present invention, the conductor assembly and the permanent magnet assembly are fabricated by modular construction. The conductor assemblies include a plurality of individual conductor elements that may be any suitable shape as desired. The individual conductor elements link together, and varying the number of individual conductor elements that are linked together varies the diameter of the conductor assembly.

According to another aspect of the present invention, the permanent magnet assembly is also fabricated using modular construction techniques similar to those used for the conductor assembly.

Brief Description of the Drawings The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a graph of torque versus slip speed for prior art permanent magnet couplers; FIGURE 2 is a perspective view of a permanent magnet coupler according to the present invention, with part of the magnet disk removed for detail; FIGURE 3 is an exploded view of the permanent magnet coupler of FIGURE 2; FIGURE 4 is a front plan view of the magnet unit of the permanent magnet coupler of FIGURE 2; FIGURE 5 is a front plan view of an alternate rotary magnet unit of the permanent magnet coupler of FIGURE 2; FIGURE 6 is a sectional view of the magnet assembly of the permanent magnet coupler of FIGURE 2 taken along the section lines 6--6 of FIGURE 4; FIGURE 7 is a front plan view of an alternate conductor assembly for the permanent magnet coupler of FIGURE 2; FIGURE 8 is a graph of torque versus slip speed for the permanent magnet coupler of the present invention; FIGURE 9 is a sectional view of the conductor assembly of FIGURE 2 taken along the section lines 9--9 of FIGURE 7; FIGURE 10 is a plan view of an alternate conductor assembly for the permanent magnet coupler of FIGURE 2; FIGURE 11 is a diagrammatic side view of an alternate permanent magnet coupler according to a first embodiment of the present invention; FIGURE 11 A is a diagrammatic side view of an alternate permanent magnet coupler according to the first embodiment of the present invention; FIGURE 11B is a diagrammatic side view of yet another permanent magnet coupler according to the first embodiment of the present invention; FIGURE 12 is a diagrammatic side view of a permanent magnet coupler according to a second embodiment of the present invention; FIGURE 12A is a diagrammatic side view of an aspect of an alternate permanent magnet coupler according to the second embodiment of the present invention; FIGURE 13 is a diagrammatic side view of a permanent magnet coupler according to a third embodiment of the present invention;

FIGURE 13 A is a diagrammatic side view of an alternate arrangement of the permanent magnet coupler according to the third embodiment of the present invention; FIGURE 1 3B is a diagrammatic side view of yet another arrangement of a permanent magnet coupler according to the third embodiment of the present invention; FIGURE 13 C is a diagrammatic side view of still another arrangement of the permanent magnet coupler according to the third embodiment of the present invention; FIGURE 14 is a diagrammatic side view of a permanent magnet coupler according to a fourth embodiment of the present invention; FIGURE 15 is a rear perspective view of a permanent magnet coupler according to a fifth embodiment of the present invention; FIGURE 16 is a diagrammatic side view of the permanent magnet coupler of FIGURE 15; FIGURE 17 is a perspective view of the magnet rotor assembly for the permanent magnet coupler of FIGURE 15; FIGURE 18 is an exploded perspective view of the magnet rotor assembly of FIGURE 17; FIGURE 19 is a perspective view of a permanent magnet used to form one of the magnetic assemblies for the magnet rotor assembly of FIGURE 17; FIGURE 1 9A is a perspective view of alternate permanent magnet for use in the magnet rotor assembly of FIGURE 17; FIGURE 20 is a perspective view of a magnet holder of the magnet assembly shown in FIGURES 18 and 19; FIGURE 21 is a perspective view of a conductor rotor assembly for the permanent magnet coupler of FIGURE 15; FIGURE 22 is an exploded perspective view of the conductor rotor assembly ofFIGURE 21; FIGURE 23 is a perspective view of a conductor rotor component of the conductor rotor assembly of FIGURE 21; FIGURE 24 is a perspective view of an alternate arrangement of the conductor rotor component of FIGURE 23; FIGURE 25A is a plan view of an alternate rotor assembly according to the present invention;

FIGURE 25B is a link subassembly for fabricating the rotor assembly of FIGURE 25A; FIGURE 26 is a perspective view of a variable speed magnetic drive coupler having a moving motor stand; FIGURE 27 is a plan view of a conductor rotor assembly formed according to the modular rotor components provided by the present invention; FIGURE 28 is a plan view of yet another conductor rotor assembly formed by the modular components used in FIGURE 27 and additional modular components; FIGURE 29 is a plan view of still another conductor rotor assembly formed from the modular components of FIGURE 28 and still more modular components; FIGURE 30 is a plan view of a four-element magnet holder of a magnet assembly according to another aspect of the present invention; and FIGURE31 is an exploded view of the four-element magnet holder of FIGURE 32; FIGURE 32 is a perspective view of a hexagon-shaped link rotor assembly according to another aspect of the present invention; FIGURE 33 shows the female side of the hexagonal link rotor assembly of FIGURE 32; FIGURE 34 shows the male side of the hexagonal link rotor assembly of FIGURE 32; FIGURE 35 is a bottom view of a magnet rotor formed using the hexagonal rotor assembly of FIGURE 32; FIGURE 36 is a bottom view of two magnet holders for use in the magnet rotor of FIGURE 35; FIGURE 37 shows a bottom view of an alternate magnet rotor formed from the hexagonal rotor assembly of FIGURE 32; FIGURE 38 is a bottom view of a conductor rotor using the hexagonal rotor assembly of FIGURE 32; FIGURE 39 is a perspective view showing the male side of another hexagonal link that may be used to make a rotor assembly according to another aspect of the present invention; FIGURE 40 is the female side ofthe hexagonal link of FIGURE 39; FIGURE 41 is a top view of an assembly of hexagonal links as shown in FIGURE 39;

FIGURE 42 is a sectional view of the assembly of FIGURE 41 taken along the section lines 42--42 of FIGURE 41; FIGURE 43 is a top perspective view of the assembly of FIGURE 41; FIGURE 44 is a perspective view of an exemplary snap-ring fastener used to connect the hexagon links of FIGURE 41; FIGURE 45 is a perspective view of the underside of the assembly of FIGURE 41; FIGURE 46 shows a detail of the snap-ring fastener of FIGURE 44 fastening the hexagon links of FIGURE 41 together; FIGURES 47 and 48 show perspective views of exemplary magnet holders that may be used with the hexagon links of FIGURES 39-46; FIGURE 49 is a perspective view of an assembled magnet rotor assembly including hexagon links, magnet holders, and magnets of FIGURES 39-48; FIGURE 50 shows an variable speed coupler embodiment of the present invention illustrating a variable resistor connected in parallel with the conductor rotor assembly; FIGURE 51 shows a embodiment of the present invention containing ferrofluid in the fixed gap between the magnets and the conductors of the coupler; FIGURE 52 shows a side perspective view of an additional hexagonal link structure for use in the invention; FIGURE 53 shows a side view ofthe hexagonal link structure of FIGURE 52; FIGURE 54 shows a top view of the hexagonal link structure of FIGURE 52; FIGURE 55 shows a side view ofthe hexagonal link structure of FIGURE 52; FIGURE 56 shows a side perspective view of three assembled hexagonal link structures such as is shown in FIGURE 52; and FIGURE 57 shows a side perspective view of two assembled hexagonal link structures such as is shown in FIGURE 52.

Detailed Description of the Preferred Embodiment FIGURES 2 and 3 show a permanent magnet coupler 10 according to the present invention. The coupler 10 includes a first shaft 12 having a first axis 14 and a second shaft 16 having a second axis 18 that is substantially aligned with the first axis 14. A rotary magnet unit 20 is mounted to rotate about the first shaft 12. The rotary magnet unit 20 includes an array of permanent magnet assemblies 22. A rotary electroconductive unit 24 is mounted to rotate about the second shaft 16. The rotary electroconductive unit 24 includes a composite conductor assembly 26. The

composite conductor assembly 26 and the permanent magnet assemblies 22 are spaced apart from each other. Rotation of the first shaft 12 causes rotation of the second shaft 16 due to electromagnetic coupling between the rotary magnet unit 20 and the electroconductive unit 24.

The first shaft 12 is suitably a motor shaft, and the second shaft 16 is suitably a load shaft. However, it is not necessary that the first shaft 12 be a motor shaft and the second shaft 16 be a load shaft. The first shaft 12 is also suitably a load shaft, and the second shaft 16 is also suitably a motor shaft. The first shaft 12 and the second shaft 16 are separated from each other. The first axis 14 and the second axis 18 are preferably substantially aligned with each other. Longitudinal and radial misalignment may be tolerated between the first and second axes 14 and 18, depending upon the gap between the rotary magnet unit 20 and the rotary electroconductive unit 24, as will be discussed more fully below.

The rotary magnet unit 20 includes a disk 28 that is coupled to the first shaft 12. The permanent magnet assemblies 22 can be spaced in an array around the perimeter of the disk 28 in a variety of arrangements as is described in detail below.

The disk 28 is attached to the first shaft 12 in any one of a number of acceptable mounting methods well known in the art, such as hubs (not shown), set screws (not shown), keys (not shown), and key-ways (not shown). The disk 28 has a radius R1.

It is desirable that the disk 28 have high strength characteristics yet be lightweight.

Therefore, the disk 28 can be made of aluminum or stainless steel, but is preferably made of a composite material, such as RytexTM. In one exemplary embodiment shown in FIGURE 11, given by way of a non-limiting example, the radius R1 is suitably approximately 8 inches, and the disk 28 has a suitable thickness T1 of approximately ¼ inch. It will be appreciated that it is not necessary that the disk 28 have these dimensions but, rather, may have any radius and thickness as desired for a particular application.

FIGURE 4 shows construction of the permanent magnet assemblies 22. The permanent magnet assemblies 22 include permanent magnets 23 that are suitably rare- earth-type magnets, such as lanthanides like samarium, cobalt, and neodymium iron boron, as are well known in the art. Neodymium iron boron magnets are presently preferred because they have a high flux density and because their domains can be preoriented before final magnetization. The permanent magnet assemblies 22 may be arranged in any number of acceptable manners. The arrangement of the permanent magnet assemblies 22 for the embodiments given by way of non-limiting examples will

be discussed later. When the permanent magnet assembly 22 includes more than one permanent magnet 23, as will be discussed later, all the permanent magnets 23 of the given permanent magnet assembly 22 are arranged such that the same pole is oriented to face a corresponding conductor. The poles of adjacent permanent magnet assemblies 22 alternate between north and south. The permanent magnets 23 each have a suitable thickness as desired for a particular application.

As shown in the embodiment given by way of the non-limiting example in FIGURES 2 and 4, the permanent magnets 23 are suitably arcuate sectors having arcuate outer and inner circumferential edges. Each permanent magnet 23 contains an arcuate concave notches 23' (FIGURE 3) on both sides of the permanent magnet 23.

The side walls of these arcuate concave notches 23' are preferably sloped downward in a tunnel-shaped configuration, as most readily shown in FIGURE 6, and as is described in detail below.

In addition to the permanent magnet 23, the permanent magnet assemblies 22 each preferably include a non-magnetic spacer 25. As shown in the embodiment given by way of non-limiting example shown in FIGURE 4, the non-magnetic spacers 25 are suitably disks. The disks are shaped and sized such that the circumference of the disk substantially conforms to the shape of the arcuate concave notch 23' in the side of the permanent magnets 23. This permits the permanent magnets 23 and the non-magnetic spacers 25 to be interleaved, as will be discussed in detail below. The non-magnetic spacers 25 are attached to the disk 28 with bolts 27 (FIGURE 2) that are suitably made of stainless steel.

It will be appreciated that the number and size of permanent magnet assemblies 22 that are mounted about the disk 28 determines the radial distance from the first axis 14 at which the permanent magnet assemblies 22 are located. Thus, the use of the permanent magnets 23 and the non-magnetic spacers 25 in the permanent magnet assemblies 22 results in a modular construction. As an example, FIGURE 5 shows that the permanent magnet assemblies 22a are radially located closer to the first axis 14 than are the permanent magnet assemblies 22 as shown in FIGURE 4.

Therefore, the number of nonmagnetic spacers 25 and permanent magnets 23 needed are less.

The modular construction of the permanent magnet assemblies 22 permits the manufacture of numerous rotary magnet units 20 having permanent magnet assemblies 22 located at various radial distances about disks 28. This manufacture

can be done without the need to retool for making disks 28 of various sizes. This represents a tremendous cost savings over known rotary magnet units.

FIGURE 6 shows a cross section of the permanent magnet assemblies 22.

Each permanent magnet 23 has a mating surface 29 that extends at an angle outward from the outer surface of the permanent magnet 23. Each non-magnetic spacer 25 includes a mating surface 31 that extends at an angle inward from the outer surface of the non-magnetic spacer 25. The angles of the mating surfaces 29, 31 substantially match so that the two surfaces align when the permanent magnetic assembly 22 is assembled. The mating surfaces 29 and 31 are suitably rough, non-machined surfaces.

Advantageously, the permanent magnets 23 and non-magnetic spacers 25 are suitably formed by being pressed in a mold of a desired shape, such as the shapes of the non- limiting examples discussed above, and then sintered. The permanent magnets 23 are then magnetized in a known manner. The permanent magnets 23 are arranged about the disk 28 at a radial distance as desired for a particular application. The mating surfaces 31 of the non-magnetic spacers 25 are inserted in an interleaved manner between the permanent magnets 23 such that the mating surfaces 31 abut against the mating surfaces 29. When the non-magnetic spacers 25 are attached to the disk 28, such as with the bolts 27, the non-magnetic spacers 25 hold down the adjacent permanent magnets 23 to the disk 28.

The rotary electroconductive unit 24 includes a disk 40 having a radius R2. It is desirable that the disk 40 have high strength characteristics and be lightweight. The disk 40 is suitably made from aluminum or from stainless steel, but is preferably made of a composite material, such as RytexTM. In one exemplary embodiment shown in FIGURE 11, given by way of a non-limiting example, the radius R2 is approximately 7.5 inches, and the disk 40 has a thickness T2 of approximately 1/4 inch.

It will be appreciated that it is not necessary that the disk 40 have these dimensions but, rather, may have any thickness as desired for a particular application. Further, it will be appreciated that any radius is acceptable that provides sufficient clearance between the permanent magnets 22 and the conductor assembly 26, as will be discussed more fully below.

As can be seen in FIGURES 2 and 3, the disk 40 extends outward and includes U-shaped flanges 21 at its circumference that extend over and around the rotary magnet unit 20. The composite conductor assembly 26 on the disk 40 consists of first, second, and third conductors 42, 44, and 46. The conductors 42, 44, and 46

are bonded within the U-shaped flange on the disk 40 on the front, top, and rear sides of the rotary magnet unit 20.

FIGURE 7 shows an alternate embodiment for a conductor assembly 26' that can be used with the permanent magnet coupler 10. An arrangement similar to the conductor assembly 26' can replace one or all of the conductors 42, 44 or 46. The conductor assembly 26' includes modular conductor subassemblies 33 and 35. The subassemblies alternate between arcuate-wedge-shaped modular conductor subassemblies 33 and truncated disk-shaped modular conductor subassemblies 35.

The modular conductive subassemblies 33 and 35 are shaped and are fitted together in much the same way as the permanent magnets 23 and the non-magnetic spacers 25 described above. The modular conductor subassemblies 33 and 35 are made from a composite material. The composite material includes a conductor, and preferably includes copper. The composite material also preferably includes a semiconductor, such as silicon, to raise the resistance of the conductor assembly 26'. A suitable composite that includes copper and silicon is GlidCop, available from SCM Metal Products, Inc. of Research Triangle Park, North Carolina. The amounts of copper and silicon can be adjusted to adjust the resistance of the conductor assembly 26' as desired. Increasing the resistance of the conductor assembly 26' is desired to increase the breakdown slip and also increase the starting torque.

FIGURE 8 shows a graph of torque versus slip speed for the present invention. The curve A of torque versus slip speed for prior art permanent magnet couplers as shown in FIGURE 1 has been reproduced in FIGURE 8. Curve B shows torque versus slip speed for the present invention when a first amount of resistance is added to the conductor assembly 26. As is known, breakdown torque occurs at a breakdown slip (sb) that is determined according to the relationship: R (1 Sb X (1 where R is the resistance of the conductor assembly 26 and X is the inductive reactance of the conductor assembly 26 at standstill. Because the value of breakdown torque is a constant for a given permanent magnet coupler, it will be appreciated that increasing the resistance R of the conductor assembly 26 increases the breakdown slip sb as shown in curve B of FIGURE 8. It will be appreciated that the breakdown slip sb as shown in curve B occurs at a higher slip speed, that is closer to standstill, than in the prior art. Curve C shows that the resistance R can be adjusted such that

breakdown torque corresponds to a breakdown slip sb having a value of one. That is, breakdown torque is generated at standstill.

It will be appreciated that increasing the breakdown slip and increasing the starting torque also increase the steady state operating slip. However, the use of a composite material, such as GhdCop, allows the conductor assembly 26 to withstand additional heat generated from increased slip. For example, GlidCop° having 90% copper by volume and 10% ceramic silicon by volume can withstand temperatures up to 1,8000F without any appreciable creep. Thus, the present invention can provide increased electromagnetic torque and withstand increased slip without warping or failure of the conductor assembly 26.

As shown in FIGURE 9, the modular conductor subassemblies 33 and 35 suitably have ferrous backings 33' and 35'. The ferrous backings 33' and 35' are suitably substantially pure iron, such as A-131 electrolytic iron available from SCM Metal Products, Inc., of Research Triangle Park, North Carolina. The ferrous backings 33' and 35' increase induction, and make up for induction losses of the copper used in the modular conductor subassemblies, as is known. However, in the presently preferred embodiment that uses a backing of substantially pure A-131 electrolytic iron, the resultant induction can be increased by a factor of about 1000 over permanent magnet couplers that include copper conductors without a backing of substantially pure iron. The iron of the presently preferred embodiment is pressed iron powder that has a nominal mesh of less than 44cm, and typically contains 70% by weight of particles less than 20cm. The particles in the preferred iron powder have an irregular, dendritic (fern-like) shape resulting in a high specific surface area.

A suitable binder, such as Silver epoxy from MasterBond or Genymer bonding agent, is used to assemble all the magnet and conductor components. This epoxy increases the conductor components efficiency at developing eddy currents in a composite layered assembly. As an alternative, the magnet pieces would be injection molded into one component. For example, the magnet holders can be injected around the magnets as one part.

FIGURE 10 shows another conductor assembly 26' that has a larger radius than the conductor assembly of FIGURE 7 because a greater number of modular conductor subassemblies 33 and 35 are utilized and because the modular conductor subassemblies 33 and 35 are approximately of the same size. While the modular conductor subassemblies 33 and 35 in FIGURES 7 and 10 are approximately in same size, modular conductor subassemblies 33 slightly differ in configuration to account

for the less dramatic curvature between adjacent subassemblies, causing the truncated wedge-shape in FIGURE 7 to become a substantially I-beam shape with rounded corners or chamfered edges in FIGURE 10. Other configurations can be provided so as to properly space the subassemblies about the circumference of the disk 40. The magnitude of the radius of the conductor assembly could also be adjusted by varying the size of the modular conductor subassemblies 33 and 35.

In the following embodiments that are given by way of non-limiting examples, it will be appreciated that many of the details of construction and operation are as described above. Accordingly, these details are not repeated. It will further be appreciated that details regarding material selection in the following non-limiting embodiments are as described above and are also not repeated.

FIGURE 11 shows an alternate embodiment of a permanent magnet coupler 10a. In contrast to the previous embodiment, the rotary magnet unit 20a of the permanent magnet coupler 10a extends outside of and around the rotary electroconductive unit 24a.

The rotary magnet unit 20a also includes a magnet mount assembly 30. The magnet mount assembly 30 includes a mount arm 32 attached to the disk 28a, extending parallel to the first axis 14, and orthogonal to the disk 28a. The mount arm 32 defines a hoop that extends along the outer circumference of the disk 28a and has an inner diameter of 2R1. The mount arm 32 is suitably a high-strength, lightweight material, such as a composite material. A suitable composite material is a fiber-reinforced thermoset composite material such as Black-Amalgon, available from Amalga Composites, Inc., of Milwaukee, Wisconsin. In the exemplary embodiments, given by way of non-limiting example, in which the radius R1 is 8 inches and the hoop 32 has an inner diameter of 16 inches, a suitable mount arm 32 is the model BA1600-B, made of Black-Amalgont, available from Amalga Composites, Inc. The mount arm 32 is suitably attached to the disk 28 in any number of methods well known in the art, such as with epoxy resin.

The permanent magnet assemblies 22a in FIGURE 11 are each formed by three magnets 34, 36, and 38 and corresponding non-magnetic spacers (not shown).

An array of the magnet assemblies 22a extends around the circumference of the disk 28a and the mount arm 32. The magnets 34, 36, and 38 are arranged in substantially a U-shape such that the opening of the U-shape is oriented to face toward the second shaft 16. In the present embodiment, the first magnet 34 is bonded in a known manner, such as with epoxy, to the mount arm 32 such that the first

magnet 34 is substantially normal to the first axis 14. The second magnet 36 abuts the first magnet 34, extends orthogonally thereto, and is bonded in a known manner, such as with epoxy, along the length of the mount arm 32 such that the second magnet 36 extends substantially parallel to the first axis 14. The third magnet 38 abuts the second magnet 36, extends orthogonally thereto, and is bonded in a known manner, such as with epoxy, to the end of the mount arm 32. The third magnet 38 extends substantially parallel to the first magnet 34.

The conductor assembly 26a in FIGURE 11 is formed by three conductor plates 42, 44, and 46. The conductor plates 42, 44, and 46 are bonded to the disk 40 in a U-shaped configuration. The first and third conductor plates 42 and 46 are bonded to the sides of the disk 40 and are oriented parallel with the first and third magnets 34 and 38. The first and third conductor plates 42 and 46 extend beyond the ends of the first and third magnets 34 and 38 toward the second shaft 16. This permits the first and third conductor plates 42 and 46 to be placed in magnetic communication with the lines of magnetic flux that extend beyond the end of the first and third magnets 34 and 38. The second conductor plate 44 is bonded to the end of the disk 40 and is oriented similarly to the second magnet 22. The second conductor plate 44 can be provided as a hoop because of its circumferential mounting. The first, second, and third magnets 34, 36, and 38 and the first, second, and third conductor plates 42, 44, and 46 are separated by an air gap of up to V2 inch in the non-limiting example of the exemplary embodiment described above. An air gap on the order of V2 inch allows misalignment between the first shaft 12 and the second shaft 16.

The orientation of the first and third magnets 36 and 38 with respect to each other may be adjusted to provide a desired gap with respect to the conductor plates 42, 44, and 46. Therefore, it will be appreciated that the first and second magnets 34 and 36 need not be normal to each other. Likewise, the second and third magnets 36 and 38 need not be normal to each other. Rather, they may be adjusted about a normal orientation as desired for a given application. In the same manner, the orientation of the conductor plates 42, 44, and 46 can be adjusted for a given application.

Each magnet 34, 36, and 38 of the U-shaped permanent magnet assembly 22a faces a corresponding plate 42, 44, and 46 of the U-shaped conductor assembly 26a.

The addition of the second magnet 36 increases the magnetic field generated by the rotary magnet unit 20 beyond that capable of being generated in known permanent

magnet couplers. The increased magnetic field contributes to an increased electromagnetic torque.

The addition of the second conductor plate 44 increases the surface area of conductors that magnetically communicate with lines of magnetic flux from permanent magnets beyond those currently known in the art. By increasing the amount of conductor that cuts through the lines of magnetic flux, an increased current is generated within the conductor. This in turn increases the electromagnetic force attracting the conductor to the permanent magnet. Thus, because force is increased, torque is increased. Thus, the embodiment of FIGURE 11 increases the amount of electromagnetic torque available to be transferred between the first shaft 12 and the second shaft 16.

FIGURE 1 lA shows an alternate arrangement of a rotary magnet unit 20b and a rotary electroconductive unit 24b of a permanent magnet coupler 10b. A disk 28b is similar to the disk 28a (FIGURE 11) and is coupled to the first shaft (not shown) in a manner similar to the disk 28a. A plurality of U-shaped permanent magnet assemblies 22b are receivably mounted within the disk 28b. Each of the U-shaped permanent magnet assemblies 22b includes first, second, and third permanent magnets 35, 37, and 39. The permanent magnets 35, 37, and 39 are oriented to each other as the magnets 34, 36, and 38 (FIGURE 11) are oriented to each other.

However, the U-shaped magnet assemblies are shaped so that the open side of the "U" extends parallel to the first axis 14, instead of normal to the first axis as was shown in FIGURE 11.

The rotary electroconductor unit 24b includes a disk 40b that is similar to the disk 40a (FIGURE 11) and is coupled to a second shaft (not shown) in a manner similar to the disk 40a. The opening of each of the U-shaped permanent magnet assemblies 22b is oriented to generally face toward the disk 40b. The disk 40b has an extension 41 that forms a hoop that is oriented toward and extends into the openings of the U-shaped permanent magnet assemblies 22b. The conductor assembly 26b is attached to the extension 41 and the side of the disk 40b facing the first disk 28b. The conductor assembly 26b includes conductor plates 43, 43a, 45, 47, and 47a. The conductor plates 43a and 47a extend on the outside and inside, respectively, of the extension 41. The conductor plate 45 extends along the distal end of the extension 41 and extends substantially parallel to the conductor plates 43a and 47a. The conductor plates 43 and 47 extend along the inside and outside circumference of the extension 41. The conductor plates 43a, 45, and 47a are suitably disks, such as the

conductor plates 42 and 46 (FIGURE 11). The conductor plates 43 and 47 are suitably hoops, such as the conductor plate 44 (FIGURE li). The operation and benefits of the coupler 11 is similar to the coupler 10 in FIGURE 11. However, in addition to the benefits of the coupler 10 in FIGURE 11, the coupler 11 of FIGURE 1 lA includes additional magnetic field contributed by the distal ends of the magnets 35 and 39, and increased current from the conductor plates 43a and 47a.

FIGURE 11B shows another alternate arrangement of a permanent magnet coupler 10c having a rotary magnet unit 20c and a rotary electroconductive unit 24c.

As with the previous embodiments, the permanent magnet coupler 10c has first and second disks 28c and 40c. The first and second disks 28c and 40c are shaped substantially the same as the disks 28a and 40a in FIGURE 11. However, the magnets and conductors in this embodiment are located in different locations. In the embodiment shown in FIGURE 11B, the first and second disks 28c and 40c each include magnets and conductors. The first disk 28c includes a first L-shaped conductor 42a that extends at right angle along a portion of the inside of the U-shaped distal end of the disk 28c and along the right side of the disk 28c. The second and third conductors 44a and 46a are attached to the second disk 40c and extend along the outer and right distal end surfaces, respectively. Each of a plurality of permanent magnet assemblies 22c includes a first permanent magnet 34a mounted on the disk 40c opposite the conductor 42a, and second and third permanent magnets 36a and 38a mounted on the disk 28c opposite the conductors 44a, 46a, respectively. When one of the disks 28c or 40c is rotated, the first magnets 34a become electromagnetically coupled to the first conductor 42a, and the second and third magnets 36a and 3 8a become electromagnetically coupled to the second conductor 44a and the third conductor 46a, respectively.

FIGURE 12 shows a permanent magnet coupler 50 according to another embodiment of the present invention. Many of the details of the construction of the coupler 50 are similar to that of the coupler 10 shown in FIGURE 11, and will not be discussed below. The coupler 50 includes an array of L-shaped permanent magnet assemblies 52 and an L-shaped conductor assembly 54. The L-shaped permanent magnet assemblies 52 each include a first permanent magnet 56 and a second permanent magnet 58. The magnets 56 and 58 of the L-shaped permanent magnet assembly 52 correspond to the magnets 36 and 38 ofthe U-shaped permanent magnet assembly 22. The L-shaped conductor assembly 54 includes a first conductor 60 and a second conductor 62. The first and second conductors 60 and 62 of the L-shaped

conductor assembly 54 correspond to the conductors 44 and 46 of the U-shaped conductor assembly 26.

The domains of the magnets 56 and 58 are suitably aligned by known techniques to balance electromagnetic forces such that no net lateral torque is generated. The remainder of the details of the construction of the coupler 50 are similar to those ofthe previously described permanent magnet couplers 10.

FIGURE 12A shows an alternate arrangement of a rotary magnet unit 20e and a rotary electroconductive unit 24e of a permanent magnet coupler 50a. A disk 28e is similar to the disk 28d (FIGURE 12) and is coupled to the first shaft (not shown) in a manner similar to the disk 28d. A disk 40e is similar to the disk 40d (FIGURE 12) and is coupled to the second shaft (not shown) in a manner similar to the disk 40d. A first plurality of L-shaped permanent magnet assemblies 52a are mounted on the disk 28e. Each of the L-shaped permanent magnet assemblies 52a includes first and second permanent magnets 56a and 58a. A second plurality of L-shaped permanent magnet assemblies 52b are mounted on the disk40e. Each of the L-shaped permanent magnet assemblies 52b includes third and fourth permanent magnets 56b and 58b.

The disk 40e includes a first L-shaped conductor assembly 54a that includes a first conductor 60a, that is suitably a copper hoop, and a second conductor 62a, that is suitably a copper disk. The disk 28e includes a second L-shaped conductor assembly 54b that includes a third conductor 60b, thus is suitably a copper hoop, and a fourth conductor 62b, that is suitably a copper disk. When one of the disks 28e or 40e is rotated, the first plurality of L-shaped permanent magnet assemblies 52a become electromagnetically coupled to the first L-shaped conductor assembly 54a, and the second plurality of L-shaped permanent magnet assemblies 52b become electromagnetically coupled to the second L-shaped conductor assembly 54b.

FIGURE 13 shows a permanent magnet coupler 70 according to another embodiment of the present invention. The permanent magnet coupler 70 includes a disk 28f, mount arm 32, and disk 40f that are similar to the disk 28a, mount arm 32, and disk 40a of FIGURE 11. The permanent magnet coupler 70 includes an array of permanent magnets 72 located along the inner side of the mount arm 32 and a conductor 74 on the end of the disk 40f. The remainder of the construction of the coupler 70 is similar to that of the permanent magnet coupler 10 and the permanent magnet coupler 50. Because the magnets 72 are located at the distance R1 from the second shaft 16, and the conductor 74 is located at the shorter distance R2 from the

second shaft 16, the electromagnetic force generated by the magnet 72 has a moment arm greater than that in known couplers. Because the moment arm is longer, the coupler 70 generates an electromagnetic torque that is greater than that generated by known couplers.

FIGURE 13A shows an alternate arrangement of a permanent magnet coupler 70a. The coupler 70a includes a disk 28g that is similar to the disk 28f (FIGURE 13) and is similarly attached to the first shaft (not shown) as the disk 28f.

The disk 28g includes a right-angle triangular mount arm 32a attached to its distal end and arranged so that the hypotenuse 76 of the mount arm extends at a 45" angle to the plane of the disk 28g. The coupler 70a also includes a disk 40g that is similar to the disk 40f (FIGURE 13) and is similarly attached to the second shaft (not shown).

A second right-angle triangular mount arm 75 is attached to the end of the disk 40g and is arranged so that its hypotenuse 77 is 45" to the plane of the disk 40g and so that the hypotenuse 77 of the second right-angle triangular mount arm 75 is located adjacent and along the hypotenuse 76 of the right-angle triangular mount arm 32a.

The disk 28g includes a first array of permanent magnets 72a located on the outer end of the hypotenuse76, and the disk 40g includes a second array of permanent magnets 72b located on the inner end of the hypotenuse 77. The disk 40g includes a first conductor 74a that is substantially aligned within the right-angle triangular mount arm 75 across from the first permanent magnets 72a, and the right-angle triangular mount arm 32a includes a second conductor 74b that is substantially aligned within the disk 28g across from the second permanent magnets 72b. The alignment between the magnets 72a and the conductor 74b, and the alignment between the magnets 72b and the conductor 74a, is suitably within 20 and is preferably within 5 to accommodate as large a gap as practicable between the permanent magnets 72a and the conductor 74a, and between the permanent magnets 72b and the conductor 74b, respectively.

Mounting the magnets 72a at an angle relative to the magnets 72 (FIGURE 13) further increases the moment arm and therefore further increases the electromagnetic torque over the amount of torque produced by the embodiment in FIGURE 13. The addition of the second array of magnets 72b and the second conductor 74b further increases the magnetic field, and thus further increases the electromagnetic torque.

FIGURE 13B shows an alternate arrangement of a permanent magnet coupler 70b. The coupler 70b is similar to the coupler 70a (FIGURE 13A) except for

orientation of the magnets and conductor mounted on the disks. A disk 28h includes first and second triangular mount arms 78, 79 that extend toward the disk 40g and upon which are mounted the permanent magnets 72a and the conductor 74b with an angle a therebetween. A disk 40h includes a triangular mount arm 75a that extends toward and between the first and second triangular mount arms 78, 79, and that is arranged for mounting the permanent magnets 72b and the conductor 74a with an angle P therebetween. As shown in the non-limiting example of FIGURE 13B, the angle a is suitably about 90", and an angle p is suitably about 2700. It will be appreciated that the angle a and the angle are not limited to angles of about 90" and 270°, respectively. Rather, the angle a and angle P may have value according to the relationship: a + p M 3600 (2 It will be appreciated that when a = 13 1800, the coupler 70b is similar to the coupler 70a (FIGURE 13A).

FIGURE 13C shows another alternate arrangement of a permanent magnet coupler 70c. The coupler 70c is an example of an alternate embodiment of the coupler 70a (FIGURE 13A) wherein a F t 1800. In the coupler 70c, a disk 28j is arranged to receivably mount the magnets 72a and the conductor 74b, and a disk 40j is arranged to receivably mount the magnets 72b and the conductor 74a. However, the disks 28j and 40j are arranged such that the magnets 72a and 72b and the conductors 74b and 74a are oriented along opposing faces of the disks 28j and 40j. It will be appreciated that, in the example shown in FIGURE 13 C, the magnets 72a and 72b and the conductors 74a and 74b are aligned substantially normal to the first and second shafts (not shown).

FIGURE 14 shows a permanent magnet coupler 80 according to another embodiment of the present invention. The permanent magnet coupler 80 includes an array of permanent magnets 82 and a U-shaped conductor assembly 84. The permanent magnets 82 are bonded to the mount arm 32 as discussed above. If desired, an additional permanent magnet 82a may be attached to the end of the permanent magnets 82 to increase the magnetic field adjacent the end of the permanent magnets 82. The U-shaped conductor assembly 84 includes first, second, and third conductors 86, 88, and 90. The conductors 86, 88, and 90 are similar to the first, second, and third conductors 42, 44, and 46 of the permanent magnet

coupler 10a (FIGURE 11). Thus, the conductors 86, 88, and 90 are suitably copper plates, as described above.

The conductor 86 is bonded to the disk 40k, as described above. The plate 90 is similarly bonded to a second disk 91 which is mounted on the second arms 16 parallel to the disk 40k. The second disk 91 is similar to the disk 40a (FIGURE 11) and is attached to the second shaft 16 similarly to the disk 40k. The disks 40k and 91 are spaced apart along the second shaft 16 such that the second conductor 88 may be placed between the first conductor 86 and the third conductor 90. The second conductor 88 is bonded to the first and third conductors 86 and 90 in a known manner. The disks 40k and 91 are physically coupled with a plurality of non-magnetic spacers 92. Coupling the disks 40k and 91 with the non-magnetic spacers 92 is considered to be well-known and will not be discussed in detail.

It will be appreciated that each face of the magnet 82 is in magnetic communication with a corresponding conductor 86, 88, and 90. Thus, the permanent magnet coupler 80 achieves the gains in increased electromagnetic torque over known couplers in a similar manner to the permanent magnet coupler 10a (FIGURE 11).

FIGURES 15 and 16 show a permanent magnet coupler 110 according to another embodiment of the present invention. The permanent coupler 110 includes a magnet rotor shaft 112 (FIGURE 16) having a magnet rotor shaft axis 114 and a conductor rotor shaft 116 having a conductor rotor shaft axis 118 that is substantially aligned with the magnet rotor shaft axis 114. A magnet rotor assembly 120 (best shown in FIGURE 17) is mounted to rotate with the magnet rotor shaft 112. The magnet rotor assembly 120 includes an array of permanent magnet assemblies 122 that form two spaced-apart hoops 125 of permanent magnet assemblies. A conductor rotor assembly 124 (FIGURE 21) is mounted to rotate with the conductor rotor shaft 116. The conductor rotor assembly 124 includes a plurality of conductor rotor components 126 that are joined together to form those spaced-apart hoops 127 of the conductor rotor components 126. The hoops 127 of the conductor rotor components 126 and the hoops 125 of the permanent magnet assemblies 122 are intertwined and spaced apart from each other. Rotation of the magnet rotor shaft 112 causes rotation of the conductor rotor shaft 116 due to electromagnetic coupling between the magnet rotor assembly 120 and the conductor rotor assembly 124.

Turning now to FIGURE 18, the magnet rotor shaft 112 is suitably a motor shaft, and the conductor rotor shaft 116 (FIGURE21) is suitably a load shaft.

However, it is not necessary that the magnet rotor shaft 112 be a motor shaft and the

conductor rotor shaft 116 be a load shaft. The magnet rotor shaft 112 is also suitably a load shaft, and the conductor rotor shaft 116 is also suitably a motor shaft. The magnet rotor shaft 112 and the conductor rotor shaft 116 are separated from each other. The magnet rotor shaft axis 114 and the conductor rotor shaft axis 118 are substantially aligned with each other. Longitudinal and radial misalignment may be tolerated between the magnet rotor shaft axis 114 and the conductor rotor shaft axis 118, depending upon the gap between the magnet rotor assembly 120 and the conductor rotor assembly 124, as will be discussed more fully below.

The magnet rotor assembly 120 includes a magnet rotor disk 128 (FIGURE 18). It is desirable that the magnet rotor disk 128 have high strength characteristics yet be lightweight. Therefore, the magnet rotor disk 128 is preferably made from a composite material, such as RytexTM. However, the magnet rotor disk 128 is suitably made of aluminum or stainless steel. In one exemplary embodiment, given by way of a non-limiting example, the magnet rotor disk 128 has a radius R1 of approximately 15 inches and a suitable thickness T1 of approximately 1/4 inch. It will be appreciated that it is not necessary that the magnet rotor disk 128 have these dimensions but, rather, may have any radius and thickness as desired for a particular application. The magnet rotor disk 128 includes a plurality of mounting holes 130. The magnet rotor assembly 120 also includes a magnet rotor plate 132.

The magnet rotor plate 132 includes a plurality of mounting holes 134. The magnet rotor plate is also preferably made from a composite material, such as RytexTM, and is also suitably made from aluminum or stainless steel. The magnet rotor assembly 120 also includes a B-lock 136. The B-lock 136 is attached to the magnet rotor shaft 112 in a known manner, and is coupled to the magnet rotor plate 132 in a well known manner. The magnet rotor plate 132 is coupled to the magnet rotor disk 128 bolts (not shown) received through the mounting holes 130 of the magnet rotor disk 128 and the mounting holes 134 of the magnet rotor plate 132. The magnet rotor assembly 120 is suitably housed within composite tubing, such as carbon-graphite high-speed tubing, as described above.

Each permanent magnet assembly 122 includes a permanent magnet 138 (FIGURE 19). FIGURE 19 shows a permanent magnet 138. The permanent magnets 138 are suitably rare-earth-type magnets, such as lanthanides like samarium, cobalt, and neodymium iron boron, as are well known in the art. Neodymium iron boron magnets are presently preferred because they have a high flux density and because their domains can be preoriented before final magnetization. As shown in

FIGURE 19, the side of the permanent magnet 138 is preferably sinusoidally curved.

The curve on the side of the permanent magnet 138 is for stress relief The shape of the permanent magnet 138 is preferably different on each side.

The magnet rotor assembly 120 includes a plurality of magnet holders 140 (FIGURE 17). FIGURE 20 shows a single magnet holder 140. Two magnet holders 140 are used on opposite sides ofthe permanent magnet to hold the magnet in the magnet rotor subassembly. The magnet holder 140 is a high-strength, high- temperature SAE standard gear-grade thermoplastic with fibers integral to the injection material. The magnet holder 140 is preferably made from Fiberstranm, available from DSM Engineering Plastics, Evansville, Indiana. The magnet holder 140 is suitably made from a polyurethane such as Isoplast 101LGF40NAT, manufactured by Dow Plastics and available from N.A. Hanna Resin Distribution.

The magnet holder 140 shown in FIGURE 20 includes a cavity 142 adapted to receive the permanent magnet 138. The magnet holders 140 include tabs 139 for interlocking adjacent magnet holders.

To form the magnet holder 140, the permanent magnet 138 is placed in a thermoplastic injection molder immediately after sintering is finished. Material as described above is injected around the magnet, forming two of the magnet holders 140 on opposite sides of the permanent magnet 138. Alternatively, two magnet holders 140 can be injected to net shape, as individual half sections, and can then be glued together over the symmetrical permanent magnet 138.

The magnet holders 140 are attached to the magnet rotor disk 128 in a known manner, such as with bolts that extend through the mounting holes 130 of the magnet rotor disk 128. It will appreciated that the size of the magnet rotor assembly 120 can be varied simply by sizing the diameter D1 of the magnet rotor disk 128 as desired and then mounting the desired number of permanent magnet assemblies 122 about the magnet rotor disk 128 as described above. The modular construction of the permanent magnet assemblies 122 permits the manufacture of numerous magnet rotor assemblies 120 having permanent magnet assemblies 122 located at various radial distances about the magnet rotor disks 128. This flexible manufacturing of making magnet rotor assemblies 120 of various sizes can be performed without retooling.

This represents a tremendous cost savings over known magnet rotor assemblies.

FIGURES 21 and 22 show a conductor rotor assembly 124 for the permanent magnet coupling 110. The conductor rotor assembly 124 includes a conductor rotor disk 144 (best shown in FIGURE 22). The conductor rotor disk 144 is constructed

from the same materials and in the same manner as the magnet rotor disk 128, as described above. In addition, the conductor rotor disk 144 includes a plurality of air cooling holes 146. The conductor rotor assembly 124 includes a conductor rotor plate 148 and a B-lock 150 that are constructed as described above for the magnet rotor plate 132 and B-lock 136. The conductor rotor disk 144 is attached to the conductor rotor shaft 116 with the conductor rotor plate 148 and the B-lock 150 in the same manner as the magnet rotor disk 128 is coupled to the magnet rotor shaft 112, as described above. In one exemplary embodiment, the conductor rotor disk 144 has a diameter D2 of about 30 inches and a thickness T2 of about 1/4 inch.

The conductor rotor assembly 124 is suitably housed within composite tubing, such as carbon-graphite high-speed tubing, as described above.

The conductor rotor assembly 124 includes a plurality of conductor rotor components 126. FIGURE 23 shows a single conductor rotor component 126. The conductor rotor component 126 is made from a suitable conductor, such as copper, iron, or steel. The conductor rotor component 126 is also suitably made from a conductive ceramic material, like zinc oxide-type, in place of copper. The conductor rotor component 126 is also suitably made from iron cobalt for increased magnetic permeability. A suitable iron cobalt conductor is Hiperco 50, available from Carpenter Technology of Reading, Pennsylvania. Copper coatings can be applied to iron cobalt, steel, or iron if the surface is raised or grooved. The copper can be cast onto a rough surface that provides a gripping system to hold the copper coating. The conductor rotor component 126 is suitably coated with silver or gold, or a combination of silver and gold for increased corrosion resistance and conductivity.

The conductor rotor component 126 is preferably made from a composite material that includes a conductor such as copper. The composite material also preferably includes material that raises the electrical resistance of the conductor rotor component 126. A suitable composite material that includes copper and a semiconductor is GlidCop, available from SCM Metal Products, Inc. of Research Triangle Park, North Carolina. GlidCop contains copper and aluminum oxide. The percentage of aluminum oxide content in the copper is preferably in a range of about .1% to 1%. A content of .1% aluminum oxide in copper yields a conductivity that is about 90% the conductivity of copper, and a 1% aluminum oxide content in copper yields a conductivity that is about 78% the conductivity of copper. The amounts of copper and aluminum oxide can be adjusted to adjust the resistance of the conductor rotor component 126 as desired. Increasing the resistance of the conductor rotor

component 126 above that of copper is desired to increase the breakdown slip and also increase the starting torque.

As shown in FIGURES 21 and 22, the conductor rotor components 126 are arranged in a substantially circular ring having a diameter of about the diameter D2 of the conductor rotor disk 144. The rings of conductor rotor components 126 are layered axially. If desired, alternating layers of rings of conductor rotor components 126 can include conductor rotor components 126 made of iron, such as a substantially pure iron like A-131 electrolytic iron available from SCM Metal Products, Inc. of Research Triangle Park, North Carolina. The iron of the presently preferred embodiment is pressed iron powder that has a nominal mesh of -325 (<44>m), and typically contains 70% by weight of particles less than 20calm. The particles in the preferred iron powder have an irregular, dendritic (fern-like) shape resulting in a high specific surface area. The use of a ferrous conductor rotor component 126 increases induction, and makes up for induction losses of the copper used in other rings of conductor rotor components 126. According to the present invention, the use of substantially pure electrolytic iron can increase induction by a factor of about 1,000 times over permanent magnet couplers that include copper conductors only with no substantially pure iron. In addition, every other conductor rotor component 126 within the same ring of conductor rotor components 126 can be a ferrous conductor rotor component 126, such as one made from substantially pure electrolytic iron, steel, or iron, to focus the flux field. Further, alternate layers of rings of the conductor rotor components 126 suitably overlap. Therefore, the permanent magnet assemblies 122 do not see a discontinuity in the conductor rotor assembly 124 because of the overlap.

The conductor rotor components 126 each include a mounting hole 152 (FIGURE 23). Layers of rings of conductor rotor components 126 are aligned such that the mounting holes 152 are aligned with each other. The number of layers of rings of conductor rotor components 152 can be adjusted as desired for a particular application. The number of rings of conductor rotor components 126 determines the thickness of the conductor hoop 127 between the permanent magnets 138. More layers can be added in the axial direction to match increased powers of permanent magnets 138. The number of layers of rings of conductor rotor components 126, as well as the thickness of each conductor rotor component 126 can be adjusted as desired to match strengths of permanent magnets 138. However, the thickness of copper and steel are preferably about the same. When magnet power is increased, the

thickness, or number of layers, should be increased. The layers of rings of conductor rotor components 126 are spaced apart by spacers 154. Bolts or pins (not shown) extend through the mounting holder 152 and the spacers 154 to hold the arrays of rotor components 126 together. In a presently preferred embodiment, the spacers 154 are made of any suitable material and have about a one-inch diameter with a length of about one and one-fourth inch. This length of the spacer 154 provides an air gap of about 1/8 inch between each permanent magnet 138 and each conductor rotor component 136. If it is desired to provide attachment of adjacent rotor components 126 to each other, a conductor rotor components 126 can be bolted or riveted together about a pivot point 156 (FIGURE 23) on each conductor rotor component 126. However, bolts can be placed anywhere in the conductor rotor component 126 or in a permanent magnet 138. Further, optional grooves 158 in the radial direction of rotation can provide up to about a 50% increase in surface area as seen by the permanent magnets 138.

FIGURE 24 shows another conductor rotor assembly 124a according to the present invention. In the conductor rotor assembly 124 shown in FIGURE 24, the mounting holes 152 are oriented inward toward the conductor rotor shaft 116.

FIGURE 25A shows an optional rotor assembly that can be made without the use of a disk. The optional rotor assembly 158 may be either a magnet rotor assembly or a conductor rotor assembly. The rotor assembly 158 is made from a plurality of link assemblies 160. Details of the link assembly 160 are shown in FIGURE 25B.

Each link assembly 160 has a rounded male end 162 and a rounded female end 164.

The male end 162 includes a peg 166 and the female end 164 includes a cavity 168.

The peg 166 and the cavity 168 are shaped and sized such that the peg 166 is received within the cavity 168 for connecting link assemblies 160. As best seen in FIGURE 25A, the female ends 164 are arranged to face radially outward and the male ends 162 are arranged to face radially inward toward a shaft such as the magnet rotor shaft 112 or the conductor rotor shaft 116. The male ends 162 may be coupled to a magnet rotor plate 132 or a conductor rotor plate 148 as desired. Further, the number of rings of link assemblies 160 may be adjusted as desired to adjust the size of the rotor assembly 158. A permanent magnet assembly 122 or a conductor rotor assembly 124 may be connected to the outwardly facing female ends 164 of the rotor assembly 158 as desired for a particular application.

FIGURE 26 shows a variable speed drive coupler 190 according to an alternate embodiment of the present invention. In the non-limiting example shown, a

motor 192 is slidably mounted on a tray 193 for slidable movement substantially transverse with the axis 14 of the motor's shaft 12. Thus, the motor shaft 12 and the motor 192 are mobile relative to the load shaft 16. A magnet rotor assembly 194 is attached to the motor shaft 12 and is received within a conductor rotor assembly 196 that is connected to the load shaft 16. The structure of the magnet rotor assembly 194 and the conductor motor assembly is similar to the embodiments in FIGURES 21-25.

The magnet rotor assembly 194 and the conductor rotor assembly 196 are coupled by a magnetic eddy current drive only when the conductor rotor assembly 196 is off center, because the conductor rotor assembly 196 is small enough that it can fit within the magnet rotor assembly without forming an eddy current. The axis ofthe motor shaft 12 and the axis ofthe load shaft 16 are substantially parallel to each other. The slidable tray 193 can be slid along an alignment channel the distance of the radial length of the magnets, or the motor can be mounted on an elevated pivot (not shown).

The slidable tray 193 or the elevated pivot acts to balance the motor 192 at the center so that very little energy is needed to move the motor 192 and magnet rotor assembly 194 in and out of the conductor rotor assembly 196 field, thereby increasing or decreasing the speed of the load shaft 16. The load shaft 16 will be at rest when the magnet rotor assembly 194 is moved to the center of the conductor rotor assembly 196. In this position, no eddy current is formed in the conductor, so no movement is initiated in the conductor rotor assembly. Thus, by moving the motor 192 back and forth, the speed of the load shaft can be varied. In an alternate embodiment, the load shaft 16 could be moved instead of the motor shaft 12, or both could be moved relative to each other.

FIGURE 27 shows an alternate conductor rotor assembly 200 according to another aspect of the present invention. In this non-limiting example, ten conductor rotor components 126a have been linked together and are further mounted to rotor units 170, which are placed substantially adjacent one another to form a generally circular pattern that may be suitably formed into a rotor. It will be appreciated that the use of these rotor units 170 will permit modular assembly of rotors. The rotor units 170 shown in this FIGURE 29 are of a substantially triangular shape, but other shapes may be used where suitable to permit modular assembly of a rotor.

FIGURE 28 shows a further alternative conductor rotor assembly according to the present invention. In this non-limiting example, 20 conductor rotor

components 126a are linked together and further mounted to an array of rotor units 172, which are themselves connected to other rotor units 170. Rotor units 172 are shown in the shape of irregular trapezoids, while rotor units 170 are the substantially triangular shape of the previous FIGURE 27, but it will be appreciated that other shapes may be used where suitable to permit modular assembly of the rotor.

The embodiment of FIGURE 28 gives yet another example of the changeability and modular component structure of the rotor assemblies of the present invention.

FIGURE 29 shows a further alternative conductor rotor assembly according to the present invention. In this non-limiting example, 30 conductor rotor components 126 are linked together and further mounted to an array of rotor units 172, which are in turn fastened to another array of rotor units 172 arranged to form a smaller diameter, and they are in turn mounted to rotor units 170. FIGURE 29 as well as the previous two figures, illustrates the modular assembly of rotors that forms an aspect of the present invention.

FIGURES 30 and 31 show an alternative magnet holder 180 capable of retaining four permanent magnets 138 in the four cavities 182 of the magnet holder.

While modularity of assembly of permanent magnet assemblies is served by using a suitable number of single magnet holders 140 as shown in FIGURE 20, it will be appreciated that in some applications a multiple-magnet holder such as the four- magnet holder 180 of FIGURE 30 will grant a manufacturing advantage and promote ease of assembly. The four magnet holder 180 incorporates cavities 182 that accept four permanent magnets 138. The use of multiple magnet holders may include any suitable numbers of magnets that may be assembled modularly.

Assembled hexagons or other suitable tessellations can be assembled into rotors. A hexagon is a preferred embodiment. FIGURE 32 shows a hexagonal link rotor assembly 210 that provides a modular assembly whereby the male side of a hexagonal link 212 interconnects with the female side of adjacent hexagonal links 212.

The joined hexagonal links 212 of the rotor assembly 210 forms a conductor rotor or a magnet rotor as desired. FIGURE 33 shows the female side of the hexagonal link and FIGURE 34 shows the male side of the hexagonal link. As can be seen, the female sides of the hexagonal links include six recessed triangles 214, all pointing toward the center of the hexagonal link 212. In contrast, the male sides of the hexagonal links 212 includes six triangular-shaped protrusions 216. Two recessed triangles 214 are fitted over two triangular-shaped protrusions 216 of an adjacent and underlying hexagonal link 212. Two more recessed triangles 214, each from two

more hexagonal links 212, fit over the other four triangular-shaped protrusions 216.

The hexagonal links 212 can continue to be built in this manner so as to form a gridwork pattern of connected hexagonal links 212.

FIGURE 35 shows a magnet rotor 220 formed using the hexagonal link rotor assembly 210 of FIGURE 32. As can be seen in the figure, the magnet rotor 220 includes two different types of magnet holders 222, 224 that extend around the circumference of the hexagonal link rotor assembly 210 and which hold a plurality of magnets 138 therein. The arrangement within the magnet holders222, 224 for holding the magnets 138 are similar to the cavities and structure described with reference to FIGURES 30 and 31. The magnet holders 222, 224, however, instead of including mounting holes, include triangular connectors 226. The triangular connectors 226 can be either protrusions or recesses, depending upon the layout of the hexagonal link rotor assembly 210 and the position of the magnet holders 222, 224. Alternatively, the connectors 226 can be located on both the top and bottom surfaces of the magnet holders 222, 224. For example, protrusions can be located on one side and recesses on the other.

As can be seen in FIGURE 36, the hexagonal pattern of the triangular connectors 226 is slightly different for the two magnet holders 222, 224. Specifically, the triangular patterns are offset 30° relative to one another so that adjacent magnet holders 222, 224 can extend from different orientations of the recess triangles 214 or the triangular-shaped protrusions 216 of the hexagonal links 212. In addition, the central axis for the triangular connectors 226 of the magnet holder 222 is slightly offset relative to the central axis of the triangular connectors 226 of the magnet holder 224 so that the magnets 138 within the magnet holders are aligned the same radial distance away from the central axis of the magnet rotor 220.

FIGURE 37 shows an alternate arrangement for a magnet rotor 230 formed from the hexagonal link rotor assembly 210. The magnet rotor 230 includes two different magnet holders 232, 234 that are alternated around the perimeter of the magnet rotor. The first of the magnet holders 232 holds four magnets, and has sides which are substantially parallel to each other and a bottom that includes two or four triangular connectors 236. The second magnet holder 234 is substantially triangularly-shaped, and includes six triangular connectors 236 for connecting to the recessed triangles 216 or triangular-shaped protrusions 216 of the hexagonal links 212 within the hexagonal link rotor assembly 210.

It can be understood that a variety of different magnet holders having a variety of different patterns of triangular connectors 236 can be provided for making a variety of different magnet rotors, or conductor rotors, for use in the present invention.

These additional embodiments can include additional hexagonal links 212 so as to form a larger hexagonal link rotor assembly 210 and to extend outward the magnet holders 232, 234, or 222, 224.

FIGURE 38 shows a conductor rotor 240 formed using the hexagonal link rotor assembly 210 of FIGURE 32. The conductor rotor 240 includes an array of alternating conductors242, 244 that extend around the circumference of the hexagonal link rotor assembly 210. The conductors 242, 244 are shaped similar to the magnet holders 222, 224 of FIGURES 35 and 36, and are arranged in the same manner about the hexagonal link rotor assembly 210.

FIGURE 39 shows another hexagonal link 250 that is used to make a rotor assembly 252 (FIGURE 49), such as a conductor rotor assembly or a magnet rotor assembly (FIGURE 49), of the hexagonal links. As shown in FIGURE39, the hexagonal link 250 includes a cylindrical peg 254 projecting from one side of the hexagonal link. The hexagonal link 250 also includes rounded concave corners 256 that are arranged to receive the central pegs of other links. As can be seen in FIGURE39, the male side of the hexagonal link 250 includes protrusions258, whereas the female side of the hexagonal link includes recesses 260 (FIGURE 40).

As can be seen in FIGURE 41, the hexagonal links 250 fit together in much the same way as the hexagonal links 212 described with reference to FIGURE 32. However, in addition to the recesses and protrusions 258, 260, the peg 254 provides additional connection support for adjacent interlinked hexagonal links 250. As can best be seen in FIGURE42, the hexagonal links 250 include rounded, concave shoulders262 through which the peg 254 extends. A snap ring 264 fits over the end of the peg and against the shoulders 262 (FIGURE 44). The final assembled snap ring 265 is shown in place in FIGURE 46.

Two types of magnet holders 240, 242 respectively shown in FIGURES 47 and 48, are used in the rotor assembly of FIGURE 49. In FIGURE 49, the magnet holders shown in FIGURES 47 and 48 cooperate as offset magnet holders. As with the previously described magnet holders 222, 224 (FIGURES 35 AND 36) and 232, 234 (FIGURE 37), the magnet holders 240, 242 shown in FIGURES 47 and 48 include connectors 244, 246 for fitting onto the recesses 260, protrusions 258, or peg 254 of the rotor assembly 252 formed by the hexagonal links 250. Also as with

the previous embodiments, the two connectors are offset relative to one another so as to provide a variety of connection arrangements.

FIGURE 50 shows a further alternative conductor rotor assembly according to the present invention. In this non-limiting example, a rotor conductor assembly 280, such as one of the previously described conductor rotor arrangements, including disks, links or other modularly interconnected conductor sub assemblies as necessary, is utilized and linked in parallel with a variable resistor 282 (not shown) to produce a variable speed permanent magnet coupler. The rotor conductor assembly 280 is used with a magnet rotor assembly (not shown). The resistance potential can be varied adjusting the variable resistor to resist or maximize the magnetic field potential in the fixed resistance portion of the conductor rotor assembly. Thus, in a permanent magnet or electromagnetic system the speed can be adjusted by varying the resistance of the conductor circuit resistance. Preferably, the variable resistor is connected in parallel across the face of the conductor rotor assembly. The fixed resistor in the conductor assembly is preferably a copper resistor, but varistors, thermistors, conductive plastics, ceramic conductors, zinc oxide type conductors, others are also suitably utilized. Semiconductors, multi-layer ferromagnetics, and magneto-resistant systems can also be layered in this configuration.

Variable speed coupling applications are numerous. For example, windmills need an increase in the field strength timed for when the blade moves in front of a mounting pole. Four stroke internal combustion engines need to have speed varied to provide load free operation just after the engine fires. Prior art variable speed technologies are not effective at varying the speed at fractions of a second and then returning to full engagement in cases like the windmill and four stroke engine.

FIGURE 51 show an additional alternate embodiment of a magnetic coupler 290 of the present invention. In the non-limiting example shown, the fixed (typically air) gap between the permanent magnets 138 of the magnet rotor assembly 292 and the conductors 294 of the conductor rotor assembly 296 is reduced to zero by adding ferrofluids 298. Ferrofluidic material is lubricating, magnetic fluid that focuses the flux field between magnets and conductors. In this respect, the ferrofluid 298 maximizes the magnetic field formed between the magnets and the conductors in the magnetic coupler. These ferrofluids 298 can also be utilized at different density levels (through dilution of the ferrofluids) to vary the magnetic field resistance between the magnets and the conductors. This ferrofluidic embodiment of the present invention can be incorporated either in conjunction with, or without the use of the variable

resistor circuit connected in parallel with conductor rotor assembly, as described above. Although the ferrofluids 298 are shown in FIGURE 51 as extending between the disks 28m and 40m, the ferrofluids could alternatively extend only between the permanent magnets 138 of the magnet rotor assembly 292 and the conductors 294 of the conductor rotor assembly 296 and serve the same purpose. Ferrofluids densities can also be varied to vary the speed of the magnetic coupler 290. Ferrofluids 298 can also be used in couplers in which the magnets a "U" shape such as is chown in FIGURE 11. The U-shape is such an embodiment helps to contain the ferrofluids.

FIGURE 52 shows an additional hexagonal link structure 300 for use in the invention. The hexagonal link structure 300 includes two disks 302, 304, the outer shapes of which substantially match the shape of the hexagonal links 250. The two disks 302, 304 extend substantially parallel to one another and are separated by a round core connector 306 (FIGURE 54). A central aperture 308 extends orthogonal to the two disks 302, 304, through the two disks 302, 304 and the a round core connector 306. Six holes 310 extend orthogonally through the two disks 302, 304 and are spaced evenly about the circumference of the disks 302, 304 approximately halfway between the central aperture 308 and the outer edges of the disks.

As can be seen in FIGURE 56, the hexagonal link structures 300 are designed so that one of the two disks 302, 304 of one of the hexagonal link structures 300 can be inserted between the two disks 302, 304 of a second hexagonal link structures 300.

A number of the hexagonal link structures 300 can be assembled to form structures (see, for example, FIGURE 55. Concave corners 312 of the two disks 302, 304 press against the round core connector 306. The round core connector 306 is preferably formed from a compressible material so as to provide a low-stress consolidated part.

The hexagonal link structures 300 described can be used to form rotor structures or, more preferably, variable resistant conductors. In the variable resistant conductors embodiment, the two disks 302, 304 serve as layered offset hexagons.

Each individual hexagon, preferably the face and back of the hexagon, is wired in parallel with a resistance circuit (not shown). This structure and wiring provides a layered structure in which the flux field can be reduced. A solid part does not have the range resistance that a layered conductor has.

Each hexagon can be wired as a resister independent of the others. To isolate each of the wired disks 302, 304, thin film of rubber tape 314 (FIGURE 53 only) can extend around the edges of the two disks 302, 304. The rubber tape 314 compresses and provides the insulation needed to separate the hexagons electrically in the radial

direction. A film 316 (FIGURE 45 only) on the face of each of the disks 302, 304 provides insulation on the face.

The U shaped magnets or any other magnet systems in the magnet couplings described above can be assembled from multiple magnets that do not have their field directly pointing into the face of the conductor. In prior art magnet couplers, some of the magnets were joined and stacked, but all magnets faced north or south and were directly pointed toward the conductor. The optimum design is a magnet composite such as is produced by Magnet-Solutions in Dublin, Ireland. Magnet Solutions provides a one Tesla magnet in a very compact design that has many small magnets shaped and arranged so as to provide optimum geometries of the magnets related directly to the field orientation needed to direct the flux where required to optimize the system. This type of magnet assembly is called a "multiple geometry magnetic field directed magnetic composite" magnet assembly. For example, in one Magnetic Solution magnet assembly, the one Tesla power was measurable in the central hole of a donut-shaped composite magnet assembly.

All the magnets described in this disclosure could be multiple geometry magnetic field directed magnetic composite magnets. The multiple geometry magnetic field directed magnetic composite magnets permit the formation of lighter components with high magnet ratings. If the same overall geometry was one single magnet, the useful power or the magnet surface would be significantly lower than multiple magnets optimized for their geometry and field. For example, low cost lower power injected magnets in the 17 MGOe range often do not form an eddy current strong enough to obtain a permanent magnet coupling. However, multiple geometry magnetic field directed magnetic composite magnet assemblies are used, the assemblies would orient the field and focus the composite of the lower power magnets into a 36 MGOe field strength at the "exit point ofthe fields", for example at the point the magnetic field was needed. This design provides a more economical magnet and a lighter magnet per torque transferring across the system.

Minimal or no iron is needed to keeper the back unused side of the multiple geometry magnetic field directed magnetic composite magnets, because the field is directed into a circuit orientation within the magnet cluster. A large heavy backing plate would not be needed in the couplings in Figure 11 - 13C to keeper the magnet cluster.

The face of the magnets in a multiple geometry magnetic field directed magnetic composite magnet assemblies would most likely not be perpendicular or

parallel to the face of the conductor or magnet rotor. Instead, there would be clusters of magnets oriented through the exit point of the magnet cluster face. Magnet orientation direction applied during the manufacture of magnets has to be applied individually to magnets assembled in the multiple geometry magnetic field directed magnetic composite magnet assemblies. It is possible to add shunting within these multiple geometry magnetic field directed magnetic composite magnet assemblies to drop the field within these clusters and vary speed. Alternatively, variable speed can be provided by moving one cluster of magnets relative to another by means such as piezoelectric mechanical movement, whereby the changed fields will cancel the potentials of the opposite magnets.

The conductors described above can be made from porous conductive carbon fibers, such as is commercially available through TechNature, Inc. of Redmond Washington. The porous conductive carbon materials can be compressed into dense materials after manufactured, and manufacturing processing can be varied to obtain various densities. Ferroelectric fluids can be absorbed physically into the voids of the porous conductive carbon materials. This feature provides a distinct advantage over copper conductive material, because copper will not physically hold ferrofluids, but the porous conductive carbon materials will. Thus, ferrofluids can be absorbed into the porous conductive carbon materials to provide a reservoir of ferrofluids to physically contact the magnets positioned at a distance.

As the magnets move relative to the ferrofluid-filled porous conductive carbon materials, the ferrofluids stiffen and form a strong mechanical "touching" bond between the magnet and conductor. This feature allows a smaller, denser coupling to be manufactured that still has all the qualities of the prior art of "air gap" couplings.

The contact is through a lubricating magnetic fluid that will compress and elongate, so the system can still be misaligned in every direction and the conductor and magnets will maintain fluid contact.

If carbon materials are used for the conductors, these materials can be "activated" to absorb gases or fluids as common as water. Carbon will absorb and "wick" the water into the conductor. The conductor components made from carbon will release their vapor or gas when heated. This provides a cooling effect on the conductor.

It is desirable in some couplings to put magnetocaloric materials in the carbon to dump heat from the system. Magnetocaloric materials heat when a magnetic field is present and cool when the magnetic field is removed. Carbon materials with

magnetocaloric materials integrated into their matrix or applied to their surface with binders will thermally cycle rapidly. This cycle can be used as a heat pipe to remove the heat generated by the slip of the coupling.

While the preferred embodiment of the invention has been illustrated and described with reference to preferred embodiments thereof, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.