System and device for rotary actuation

Abstract

A rotary actuating device configured to effect a rotational motion on a rotor comprising a conductive material is provided. The rotary actuating device comprises a magnetic array defining a throughgoing longitudinal channel. The magnetic array comprises a plurality of serially intertwined substantially helical magnetic arrangements each having an inner surface facing the channel. Each of the helical magnetic arrangements is configured to provide magnetization at its inner surface in a direction which is oriented 90° relative to a direction of magnetization of the inner surface of the magnetic arrangement adjacent thereto. The relative rotational motion of the rotor is effected as the rotor moves longitudinally through the channel of the rotary actuating device.

Description

[0001] SYSTEM AND DEVICE FOR ROTARY ACTUATION

[0002] TECHNOLOGICAL FIELD

[0003] The presently disclosed subject matter relates to systems and devices for imparting a relative rotational motion, and in particular to systems and devices utilizing magnetic fields therefor.

[0004] BACKGROUND

[0005] The need to impart rotational motion to linearly moving objects and vice versa is well known. Firearms and artillery are commonly formed with rifled barrels, in which spiral grooves formed on interior surfaces of the barrels engage with projectiles as they move therethrough, thereby causing the projectile to spin, providing improved aerodynamic stability and accuracy.

[0006] Some energy harvesting systems are designed to exploit linear motion, for example the up-and-down motion of a buoy in the ocean, to provide rotational motion to drive a generator, thereby facilitating electricity production.

[0007] SUMMARY

[0008] According to aspects of the presently disclosed subject matter, there is provided a rotary actuating device configured to effect a rotational motion on a rotor comprising a conductive material;

[0009] the rotary actuating device comprising a magnetic array defining a throughgoing longitudinal channel, the magnetic array comprising a plurality, e.g., four, of serially intertwined substantially helical magnetic arrangements each having an inner surface facing the channel;

[0010] the magnetic arrangements are each configured to provide magnetization at its inner surface in a direction which is oriented 90° relative to a direction of magnetization of the inner surface of the magnetic arrangement adjacent thereto;wherein the relative rotational motion is effected as the rotor moves longitudinally through the channel of the rotary actuating device.

[0011] Two of the magnetic arrangements may be non-adjacent and configured to be magnetized in oppositely oriented longitudinal directions.

[0012] Each of the longitudinally magnetized magnetic arrangements may be formed as a monolithic helix.

[0013] Each of the longitudinally magnetized magnetic arrangements may be premagnetized.

[0014] Each of the longitudinally magnetized magnetic arrangements may comprise a permanent magnet, for example comprising a rare-earth magnet.

[0015] Two of the magnetic arrangements may be non-adjacent and configured to be magnetized in oppositely oriented radial directions.

[0016] Each of the radially magnetized magnetic arrangements may be formed as a monolithic helix.

[0017] Each of the radially magnetized magnetic arrangements may be nonpremagnetized.

[0018] Each of the radially magnetized magnetic arrangements comprises a ferromagnetic material, for example comprising steel and / or vanadium permendur.

[0019] The magnetic arrangements may be arranged such that facing inner surfaces thereof are altematingly (i.e., along the longitudinal direction) configured to be magnetized:

[0020] • in directions which are oriented 180° to their respective facing inner surfaces, and

[0021] • in the same direction as their respective facing inner surfaces.

[0022] The magnetic arrangements may be formed as isoperiodic helices, wherein the average longitudinal width of the helices is substantially one quarter of their period.

[0023] The magnetic arrangements may be formed as isoperiodic helices, wherein the longitudinal width of each helix is substantially the same as the helix not adjacent thereto. Two non-adjacent helices may be configured to be magnetized in oppositely oriented longitudinal directions and two non-adjacent helices may be configured to be magnetized in oppositely oriented radial directions, wherein:a width ratio of the longitudinal width of each of the radially magnetized helices to the longitudinal width of each of the longitudinally magnetized helices is between about 0.4 and about 0.6; and / or

[0024] a radius ratio of the outer radius of each of the radially magnetized helices to the outer radius of each of the longitudinally magnetized helices is between about 0.65 and about 0.85.

[0025] The width ratio may be about 0.56 and / or the radius ratio may be about 0.75. All of the helices may have substantially the same longitudinal widths.

[0026] The magnetic array may comprise a plurality, e.g., four, of linear Halbach arrays, each of the Halbach arrays comprising a plurality of magnets disposed such that the magnetic orientation of each magnet is oriented 90° relative to magnetic orientation of the magnet adjacent thereto, the Halbach arrays being arranged such that the magnetic orientation of inner surfaces of longitudinally aligned magnets of each of the Halbach arrays are different from one another.

[0027] The magnetic array may comprise one or more electromagnets configured to magnetize at least some of the magnetic arrangements.

[0028] The rotary actuating device may further comprise an actuator configured to facilitate relative longitudinal motion of the rotor through the channel of the rotary actuating device.

[0029] The rotor may be made of a material having a relative magnetic permeability less than about 1, i.e., up to a value slightly exceeding 1 to the extent that it is still considered paramagnetic.

[0030] The rotor may comprise a paramagnetic material, for example comprising aluminum.

[0031] The rotor may comprise a diamagnetic material, for example comprising copper. The rotor may be substantially longitudinally elongated.

[0032] The rotor being spherical.

[0033] According to other aspects of the presently disclosed subject matter, there is provided a rotary actuating system comprising a rotary actuating device and at least one rotor, each as described above.According to other aspects of the presently disclosed subject matter, there is provided a method of effecting a rotational motion on a rotor comprising a conductive material, the method comprising:

[0034] providing a rotary actuating device as described above; and

[0035] moving the rotor longitudinally through the channel of the rotary actuating device; wherein a magnetic field created by the magnetic array within the channel effects the rotational motion on the rotor as it moves therethrough.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0038] Fig. 1A is a perspective view of a rotary actuating device according to the presently disclosed subject matter;

[0039] Fig. IB is a perspective cross-sectional view of the rotary actuating device illustrated in Fig. 1 A taken along a longitudinal plane thereof;

[0040] Fig. 1C is a cross-sectional view of the rotary actuating device illustrated in Fig.

[0041] 1 A taken along a transverse plane thereof;

[0042] Fig- 2 is a sectional view of an example of the rotary actuating device according to the presently disclosed subject matter, showing magnetic fields;

[0043] Fig- 3 is a perspective cross-sectional view of another example of a rotary actuating device according to the presently disclosed subject matter taken along a longitudinal plane thereof;

[0044] Figs. 4A and 4B are exploded perspective and front views of another example of the rotary actuating device illustrated in Fig. 1 A;

[0045] Fig. 5A is a perspective view of another example of a rotary actuating device comprising four linear Halbach arrays according to the presently disclosed subj ect matter; and

[0046] Figs. 5B through 5E are cross-sectional views taken, respectively, along lines B-B, C-C, D-D, and E-E in Fig. 5A.DETAILED DESCRIPTION

[0047] As illustrated in Figs. 1A and IB, there is provided a rotary actuating device, which is generally indicated at 10, configured to impart rotational motion on a rotor 12 moving linearly therethrough.

[0048] The rotary actuating device 10 comprises a magnetic array 14, which extends along a longitudinal axis Z, and which defines a throughgoing channel 16 extending along the longitudinal axis, configured for linear movement of the rotor 12 therethrough, during which a rotational motion is imparted thereof. The cross-sectional shape of the channel 16, i.e., in a direction transverse to the longitudinal axis Z, may be uniform along all of most of its length; however, it may be advantageous for some applications to provide a channel having a varying cross-sectional shape. According to some examples, the cross-sectional shape of the channel 16 is substantially round.

[0049] The magnetic array 14 comprises four magnetic arrangements, i.e., first, second, third, and fourth magnetic arrangements 18a, 18b, 18c, 18d, comprising, respectively, first, second, third, and fourth inner surfaces 20a, 20b, 20c, 20d facing the channel 16. Each of the magnetic arrangements 18 is substantially helically formed with the same pitch angle, and they are serially intertwined with each other, i.e., all four magnetic arrangements are helically formed along a common axis, and each is offset with respect to the other magnetic arrangements along the axis (e.g., the threads of a multi-start thread can be described as “intertwined”). For the sake of clarity, in the accompanying drawings the first helical magnetic arrangement 18a is shaded in order to serve as a reference point and to facilitate visualizing the periodic nature of the helical magnetic arrangements. A longitudinal path along the wall of the channel 16 will successively and sequentially — i.e., in order and repeating the same order — traverse the first, second, third, and fourth inner surfaces 20a, 20b, 20c, 20d of the magnetic arrangements 18. Accordingly, the helical magnetic arrangements 18 are mutually isoperiodic, i.e., they all are characterized by the same period. According to some examples, each of the helical magnetic arrangements 18 is formed monolithically, i.e., out of a single piece of material.

[0050] In the present disclosure, different elements indicated by a single reference numeral and distinguished by their trailing letters may be collectively indicated using the reference numeral without a trailing letter, e.g., reference numeral 18 may be used tocollectively refer to some or all of magnetic arrangements 18a, 18b, 18c, and 18d, for example as clear from context. Moreover, the ordinal numerals first, second, etc., are used herein the specification and appended claims to indicate the position in the sequence of intertwined helical magnetic arrangements; to the extent that it indicates their order, it is for clarity of description only, and is not to be construed as describing or limiting to an orientation of the helical magnetic arrangements, for example with reference to the direction of linear movement of the rotor 12.

[0051] Herein the specification and appended claims, descriptions of the magnetic arrangement being “substantially” helically formed includes not only that it may be formed as a helix for example as illustrated, but also that it follows and / or comprises elements which are arranged along a generally helical or spiral path about the longitudinal axis Z of the magnetic array 14.

[0052] The helical magnetic arrangements 18 may be provided such that their average longitudinal width w is substantially one quarter of their period, i.e., the total longitudinal width is substantially the length of the period. Accordingly, they are arranged close enough to one another with substantially no gaps in between, i.e., sufficiently close to each other to ensure that the magnetic arrangements 18 do not move relative to one another, or that any such movement is minimized so as not to adversely affect operation, e.g., in view of operational requirements. According to some examples, this is provided to the extent practicable given manufacturing and / or other relevant constraints.

[0053] According to some examples, some or all of the inner surfaces 20 have different longitudinal widths w. For example, the first and third inner surfaces 20a, 20c may have the same first longitudinal width wi as each other, and the second and fourth inner surfaces 20b, 20d may have the same second longitudinal width W2, different from the first longitudinal width wi, as each other, for example as described below with reference to and as illustrated in Fig. 3. Accordingly, each of the inner surfaces 20 may have a different longitudinal width than the two inner surfaces adjacent thereto, and the same longitudinal width as the inner surface it is not adjacent to (e.g., first inner surface 20a is adjacent to fourth and second inner surfaces 20d, 20b and has a different longitudinal width therefrom, and is not adjacent to third inner surface 20c which has the same longitudinal width).According to examples in which non-adjacent inner surfaces 20 of the helical magnetic arrangements 18 have the same width, facing inner surfaces 20 — i.e., those which, at a given longitudinal position, are disposed at opposite positions, rotated 180° from each other about the longitudinal axis Z — are aligned with one another, i.e., each inner surface is disposed opposite an inner surface of a different helical magnetic arrangements, typically one which is not adjacent thereto.

[0054] Each of the helical magnetic arrangements 18 is magnetized and / or configured to be magnetized with a predetermined direction of magnetization, i.e., the orientation of the magnetic field, at each of their respective inner surfaces 20. According to some examples, the first and third helical magnetic arrangements 18a, 18c are longitudinally magnetized in opposite directions, and the second and fourth helical magnetic arrangements are radially magnetized in opposite directions. Accordingly:

[0055] • the first inner surface 20a is magnetized in a first longitudinal direction; • the second inner surface 20b is magnetized in a first radial direction, e.g., inwardly, which is oriented 90° relative to the direction of magnetization of the first inner surface 20a adjacent thereto and preceding it;

[0056] • the third inner surface 20c is magnetized in a second longitudinal direction opposite the first longitudinal direction, which is oriented 90° relative to the direction of magnetization of the second inner surface 20b adjacent thereto and preceding it, and 180° relative to the direction of magnetization of the first inner surface 20a; and

[0057] • the fourth inner surface 20d is magnetized in a second radial direction opposite the first radial direction, e.g., outwardly, which is oriented 90° relative to the direction of magnetization of the third inner surface 20c adjacent thereto and preceding it, and in the same direction as the second inner surface 20b.

[0058] The above repeats along the length of the magnetic array 14, i.e., the first inner surface 20a is magnetized in the first longitudinal direction, which is oriented 90° relative to the direction of magnetization of the fourth inner surface 20d adjacent thereto and preceding it, etc.

[0059] According to some examples, e.g., wherein non-adjacent inner surfaces 20 have the same width, alternating facing inner surfaces 20 are magnetized in opposite directionsas their respective facing inner surfaces, i.e., their magnetic fields are oriented 180° relative to each other, and the other alternating facing inner surfaces 20 are magnetized in the same direction as their respective facing inner surfaces. Accordingly, at a given longitudinal position of the magnetic array 14, facing first and third inner surfaces 20a, 20c are magnetized in opposite longitudinal directions, and facing second and fourth inner surfaces 20b, 20d are magnetized in the same direction (i.e., since they are magnetized in opposite radial directions, the inner-facing radial magnetization of one inner surface is in the same direction as the outer-facing radial magnetization of its respective facing inner surface).

[0060] According to some examples, the first and third helical magnetic arrangements 18a, 18c — i.e., those having inner surfaces 20a, 20c which are longitudinally magnetized — are premagnetized, for example being made of a permanent magnet such as a rare-earth magnet being longitudinally magnetized. According to these examples, the second and fourth helical magnetic arrangements 18b, 18d, i.e., those having inner surfaces 20b, 20d which are radially magnetized, are non-premagnetized, for example being made of a material having a high magnetic permeability, such as a ferromagnetic material, e.g., steel and / or vanadium permendur. The non-premagnetized helical magnetic arrangements 18b, 18d redirect magnetic fields from the adjacent premagnetized helical magnetic arrangements 18a, 18c, such that inner surfaces 20b, 20d exhibit radial magnetization, for example as illustrated in Fig. 2. (Directions of magnetization / magnetic field are indicated in the accompanying drawings by arrows; a circle with a dot at its center [O] indicates magnetization directed toward the viewer, and circle with an inscribed cross [®] indicates magnetization directed away from the viewer.) It will be appreciated that Fig. 2 is a simplified representation of the magnetic fields and is provided for illustration purposes only; it does not include deviations owing to boundary effects, etc.

[0061] As mentioned above and as illustrated in Fig. 3, the longitudinal width wi of the longitudinally non-premagnetized second and fourth helical magnetic arrangements 18b, 18b may be different than the longitudinal width W2 of the longitudinally premagnetized first and third helical magnetic arrangements 18a, 18c. According to some examples, the ratio w .W2 is between about 0.4 and about 0.6, for example about 0.56.According to some examples, the outer radius Ri of the longitudinally nonpremagnetized second and fourth helical magnetic arrangements 18b, 18d may be different than the outer radius R2 of the longitudinally premagnetized first and third helical magnetic arrangements 18a, 18c. According to some examples, the ratio R1.R2 is between about 0.65 and about 0.85, for example about 0.75. According to some examples, each of the helical magnetic arrangements may have the same inner radius.

[0062] It has been found that helical magnetic arrangements 18 with ratios w .W2 and / or R1.R2 as per the above exhibit favorable properties, for example an increase in gain of the magnetic flux density at the longitudinal axis Z. However, it will be appreciated this may be relevant for particular conditions, and one having skill in the art may find that other ratios provide superior properties, by calculation (e.g., using finite element analysis) and / or by experimentation.

[0063] As illustrated in Figs. 4A and 4B, according to some examples the magnetic array 14 may comprise helical magnetic arrangements 18, some or each of which are formed from separate elements, i.e., are not monolithically formed. According to these examples, a non-premagnetized core 24, comprising the second and fourth helical magnetic arrangements 18b, 18d (for clarity of illustration, the helical magnetic arrangements are not indicated by reference numerals in Figs. 4A through 4C) is provided. Four premagnetized sections 26a, 26b, 26c, and 26d are provided, each comprising a longitudinally extending half of one of the first and third helical magnetic arrangements 18a, 18c, optionally rigidly held in place, for example by a longitudinal rail 28. The half helices of corresponding premagnetized sections 26 fit together over the non-premagnetized core 24, cooperating to form the first and third helical magnetic arrangements 18a, 18c, e.g., the first and third premagnetized section 26a, 26c are magnetized in a first longitudinal direction and cooperate to form the first helical magnetic arrangement 18a, and the second and fourth premagnetized section 26b, 26d are magnetized in a second longitudinal direction opposite the first longitudinal direction and cooperate to form the third helical magnetic arrangement 18c. Such magnetic arrays 14 may be useful, e.g., wherein it is necessary to mount it on a turret or other cylinder having a high magnetic permeability which would hinder sliding magnetic helices thereon, especially when it the mounting must be done in the field.According to any of the above examples, the inner surface of the channel 16 may be provided with a sleeve (not illustrated). According to some examples, the inner surface of the channel 16 may be formed with rifling, longitudinal or circumferential grooves, knurling, and / or any other suitable texture to further affect the motion of the rotor 12 as it moves linearly through the channel, for example as is known in the art. One or more supports (not illustrated) may be provided extending inwardly to the channel 16, for example to facilitate alignment, etc., of the rotor 12 as it moves linearly through the channel.

[0064] The rotary actuating device 10 may comprise a linear actuator (not illustrated) configured to facilitate movement of the rotor 12 linearly through channel 16 of the magnetic array 14. The linear actuator may be any suitable arrangement, for example depending on the rotor 12, particulars of the use case, etc.

[0065] The rotor 12 comprises a conductive material. The material of the rotor 12 may have a relative magnetic permeability less than about 1, for example being a diamagnetic or a paramagnetic material. According to some examples, it may comprise copper, aluminum, alloys thereof, and / or any other suitable material. The rotor 12 may have any suitable shape including, but not limited to, rod-shaped, spherical, etc. According to some examples, the rotor 12 is substantially longitudinally elongated, e.g., the length of the rotor 12, i.e., the dimension about the longitudinal axis about which rotational motion is imparted, is at least two times the largest dimension in a perpendicular direction. The rotational motion imparted on such a rotor 12 may facilitate stabilization thereof, for example if the rotor is a projectile.

[0066] The speed and direction of the imparted rotation depend, inter alia, on the geometries of the magnetic arrangements 18 and of the rotor 12, the magnetic forces, and the linear speed of the rotor 12 through the channel. For example, a magnetic array 14 as described above comprising magnetic arrangements 18 formed as helical elements gives rise to a magnetic field within the channel 16. The x- and -components (i.e., the components in perpendicular radial directions) of the magnetic field B at a given point along the longitudinal axis Z may be described as follows:

[0067]

[0068]

[0069] <

[0070] where z is the longitudinal coordinate, i.e., the point along the longitudinal axis Z, Buis the peak magnetic field strength, i.e., the peak magnetic field strength in the helical configuration, h is the wavenumber given by Zidd in which d is the period of the helix, and (p is the angular offset of the magnetic field pattern. When the rotor 12 moves linearly through the channel 16 along its longitudinal axis Z, it experiences a time-varying magnetic flux (owing to its motion through the magnetic flux which varies along the axis), thereby inducing a circular electromotive force e in the form of eddy currents. Faraday’s law of induction describes the electromotive force:

[0071]

[0072] wherein is the magnetic flux. The eddy currents interact with the magnetic field, giving rise to a torque on the rotor 12, imparting the rotational motion thereon. The force F acting on the rotor 12 as a result of the torque may be described by the Lorentz force law:

[0073] F = (j x B)dV

[0074] where J is the current density, B is the magnetic field, and the integration is performed over the volume of the rotor.

[0075] As illustrated in Figs. 5A through 5E, according to some examples the magnetic array 14 comprises four longitudinal Halbach arrays, each indicated at 30. The Halbach arrays 30 define a channel 16 therebetween extending along a longitudinal axis Z. Each of the Halbach arrays 30 comprises a plurality of Halbach magnets 32, which may be bar magnets, arranged longitudinally in a repeating pattern. A first Halbach magnet 32a is disposed such that its inner surface 34a is magnetized in a first longitudinal direction, a second Halbach magnet 32b is disposed such that its inner surface 34b is magnetized in a first, e.g., inward, radial direction, a third Halbach magnet 32c is disposed such that its inner surface 34c is magnetized in a second longitudinal direction being opposite (i.e., oriented 180° relative to) the first longitudinal direction, and a fourth Halbach magnet 32d is disposed such that its inner surface 34d is magnetized in a second, e.g., outward, radial, direction being opposite the first radial direction.It will be appreciated that while in the context of some examples of the presently disclosed subject matter and the appended claims, e.g., as described herein with reference to Figs. 5A through 5E, the term “radial direction” is technically a misnomer, the term is used in order to maintain consistency of disclosure / recitation of scope, and is to be understood in the same sense as the term “transverse direction,” mutatis mutandis.

[0076] According to some examples, the second and fourth Halbach magnet 32b, 32d, i.e., those whose inner surfaces 34b, 34d are magnetized in radial directions, may be nonpremagnetized, similar to as described above with reference to and illustrated in Fig. 2, mutatis mutandis.

[0077] The Halbach arrays 30 are arranged such that at each longitudinal position along the magnetic array 14, the first and third Halbach magnets 32a, 32c are disposed on opposite sides of the longitudinal axis Z with their respective inner surfaces 34a, 34c facing each other, and the second and fourth Halbach magnets 32b, 32d are disposed between the first and third Halbach magnets, on opposite sides of the longitudinal axis Z with their respective inner surfaces 34b, 34d facing each other.

[0078] It will be appreciated, for example as illustrated in Figs. 5B through 5E, that each longitudinally successive set of four Halbach magnets 32 (i.e., those at the same longitudinal position) is shifted 90° relative to the previous set, i.e., the second Halbach magnet 32b is in the same angular position as is the first Halbach magnet 32a in the longitudinally previous set of Halbach magnets, the third Halbach magnet 32c is in the same radial position as is the second Halbach magnet 32b in the longitudinally previous set of Halbach magnets, etc. Accordingly, correspondingly magnetized (and numbered in the accompanying drawings) Halbach magnets 32 are arranged in a helical pattern about the longitudinal axis Z, i.e., they follow a generally spiral path about the longitudinal axis Z, and thus collectively constitute a helical magnetic arrangement, i.e., all of the first Halbach magnets 32a constitute a first helical magnetic arrangement, etc.

[0079] According to any of the above examples, one or more of the magnetic arrangements may comprise one or more electromagnets configured to be activated to induce a suitable magnetic field at one or more inner surfaces thereof, mutatis mutandis.

[0080] While the presently disclosed subject matter refers to imparting rotational motion on the rotor 12, i.e., causing it to spin, this is by way of example only, and all motionsdescribed herein, unless otherwise clear from context, refer to relative motion. Moreover, descriptions herein of rotational motion being imparted as a result of linear motion of the rotor imply relative linear motion being imparted as a result of rotational motion. Accordingly, the presently disclosed subject matter includes, but is not limited to:

[0081] • rotational motion being effected on the rotor as a result of its linear motion within the rotary actuating device;

[0082] • rotational motion being effected on the rotary actuating device as a result of linear motion of the rotor therewithin, e.g., wherein the rotor is constrained from rotating;

[0083] • relative linear motion (motion of the rotor with respect to the rotary actuating device and / or vice versa) being effected between the rotary actuating device and the rotor as a result of relative rotational motion therebetween. Herein the specification and appended claims, the term “conductive material” refers to materials that are generally regarded as conductors, i.e., being recognized in the art as exhibiting significant electrical conductivity, thereby allowing efficient flow of electric current with low resistance therethrough, and excludes materials which are generally regarded as insulators. In particular, the level of electrical conductivity is such that, when moving through the time-varying magnetic flux for example as described above, an electromotive force is induced thereon which is sufficient to impart a significant rotational motion.

[0084] Herein the specification and appended claims, unless otherwise clear from context the term “magnetized” is not to be construed as being limited to describing an element which produces a magnetic field, but also includes an element which is configured to be so magnetized, including, but not limited to, a non-premagnetized materiel, e.g., a ferromagnetic material prior to inducing magnetization, an electromagnet with no current through its coils, etc. Similarly, unless otherwise clear from context the term “configured to be magnetized” includes descriptions of elements which are magnetized, including, but not limited to, a premagnetized material (e.g., a permanent magnet or a ferromagnetic material with an induced magnetic field), an operating electromagnetic, etc. In general, during use of the rotary actuating device 10, elements described as being “configured to be magnetized” are magnetized.Explanations offered herein for physical phenomena — e.g., the description of induction of radial magnetic fields on non-premagnetized materials owing to the effect they have on the magnetic flux of premagnetized materials, formulas describing magnetic fields, etc. — are presented in order to provide possible rationales and / or practical insights for the observed phenomena, with the recognition that such explanations may be unsettled or contested, may be found to be incomplete or incorrect, and / or may contribute only partially to the phenomena observed. Despite these potential limitations, such explanations may offer useful guidance, and therefore have been included as part of the present disclosure. Accordingly, the presently disclosed subject matter is not to be constrained or undermined by any theory or explanation.

[0085] It will be recognized that examples, embodiments, modifications, options, etc., described herein are to be construed as inclusive and non-limiting, i.e., two or more examples, etc., described separately herein are not to be construed as being mutually exclusive of one another or in any other way limiting, unless such is explicitly stated and / or is otherwise clear. Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations, and modifications can be made without departing from the scope of the presently disclosed subject matter, mutatis mutandis.

Claims

1. CLAIMS:

1. A rotary actuating device configured to effect a rotational motion on a rotor comprising a conductive material;the rotary actuating device comprising a magnetic array defining a throughgoing longitudinal channel and being configured to produce within the channel a magnetic field having a longitudinally varying magnetic flux, the magnetic array comprising a plurality of serially intertwined substantially helical magnetic arrangements each having an inner surface facing the channel;the inner surface of each of the magnetic arrangements being configured to be magnetized in a direction which is oriented 90° relative to a direction of magnetization of the inner surface of the magnetic arrangement adjacent thereto;wherein the rotary actuating device is configured such that the magnetic field, for the length of the magnetic array, induces an electromotive force in the conductive material of the rotor as the rotor moves longitudinally through the channel, thereby effecting the rotational motion.

2. The rotary actuating device according to claim 1, wherein two of the magnetic arrangements are non-adj acent and are configured to be magnetized in oppositely oriented longitudinal directions.

3. The rotary actuating device according to claim 2, wherein each of the longitudinally magnetized magnetic arrangements is formed as a monolithic helix.

4. The rotary actuating device according to any one of claims 2 and 3, wherein each of the longitudinally magnetized magnetic arrangements is premagnetized.

5. The rotary actuating device according to claim 4, wherein each of the longitudinally magnetized magnetic arrangements comprises a permanent magnet.

6. The rotary actuating device according to claim 5, wherein the permanent magnet comprises a rare-earth magnet.

7. The rotary actuating device according to any one of the preceding claims, wherein two of the magnetic arrangements are non-adj acent and are configured to be magnetized in oppositely oriented radial directions.

8. The rotary actuating device according to claim 7, wherein each of the radially magnetized magnetic arrangements is formed as a monolithic helix.

9. The rotary actuating device according to any one of claims 7 and 8, wherein each of the radially magnetized magnetic arrangements is non-premagnetized.

10. The rotary actuating device according to claim 9, wherein each of the radially magnetized magnetic arrangements comprises a ferromagnetic material.

11. The rotary actuating device according to claim 10, wherein the ferromagnetic material comprises steel and / or vanadium permendur.

12. The rotary actuating device according to any one of the preceding claims, wherein the magnetic arrangements are arranged such that facing inner surfaces thereof are alternatingly configured to be magnetized in directions which are oriented 180° to their respective facing inner surfaces, and in the same direction as their respective facing inner surfaces.

13. The rotary actuating device according to any one of the preceding claims, the magnetic arrangements being formed as isoperiodic helices, wherein the average longitudinal width of the helices is substantially one quarter of their period.

14. The rotary actuating device according to any one of the preceding claims, the magnetic arrangements being formed as isoperiodic helices, wherein the longitudinal width of each helix is substantially the same as the helix not adjacent thereto.

15. The rotary actuating device according to claim 14, wherein two non-adjacent helices are configured to be magnetized in oppositely oriented longitudinal directions and two non-adjacent helices are configured to be magnetized in oppositely oriented radial directions, wherein:a width ratio of the longitudinal width of each of the radially magnetized helices to the longitudinal width of each of the longitudinally magnetized helices is between 0.4 and 0.6; and / ora radius ratio of the outer radius of each of the radially magnetized helices to the outer radius of each of the longitudinally magnetized helices is between 0.65 and 0.85.

16. The rotary actuating device according to claim 15, wherein the width ratio is 0.56 and / or the radius ratio is 0.75.

17. The rotary actuating device according to claim 14, wherein all of the helices have substantially the same longitudinal widths.

18. The rotary actuating device according to claim 1, the magnetic array comprising a plurality of linear Halbach arrays, each of the Halbach arrays comprising a plurality of magnets disposed such that the magnetic orientation of each magnet is oriented 90° relative to magnetic orientation of the magnet adjacent thereto, the Halbach arrays being arranged such that the magnetic orientation of inner surfaces of longitudinally aligned magnets of each of the Halbach arrays are different from one another.

19. The rotary actuating device according to any one of the preceding claims, the magnetic array comprising one or more electromagnets configured to magnetize at least some of the magnetic arrangements.

20. The rotary actuating device according to any one of the preceding claims, comprising four magnetic arrangements.

21. The rotary actuating device according to any one of the preceding claims, further comprising an actuator configured to facilitate relative longitudinal motion of the rotor through the channel of the rotary actuating device.

22. The rotary actuating according to any one of the preceding claims, wherein the rotor is made of a material having a relative magnetic permeability less than about 1.

23. The rotary actuating device according to claim 22, wherein the rotor comprises a paramagnetic material.

24. The rotary actuating device according to claim 23, wherein the paramagnetic material comprises aluminum.

25. The rotary actuating device according to claim 22, wherein the rotor comprises a diamagnetic material.

26. The rotary actuating device according to claim 25, wherein the diamagnetic material comprises copper.

27. The rotary actuating device according to any one of the preceding claims, the rotor being substantially longitudinally elongated.

28. The rotary actuating device according to any one of the preceding claims, the rotor being spherical.

29. A rotary actuating system comprising a rotary actuating device and at least one rotor, each according to any one of the preceding claims.

30. A method of effecting a rotational motion on a rotor comprising a conductive material, the method comprising:providing a rotary actuating device according to any one of claims 1 through 28; andmoving the rotor longitudinally through the channel of the rotary actuating device; wherein a magnetic field created by the magnetic array within the channel effects the rotational motion on the rotor as it moves therethrough.

Images