Non-contact power transmission and its motion device

Abstract

A contactless electric motion device in which electric power is made available contactlessly from a stationary part to a movable part includes a stator, the cross section of which includes a magnetizable outer wall surrounding a conductor and a hollow space, the magnetizable outer wall having discontinuities that form an air gap, and the stator and hollow space in longitudinal cross section form a rail. The movable part has a shoe or slider that fits within the hollow space to travel along the rail, and the mover fills the air gap contactlessly at any given location as it passes. When the air gap is closed, a magnetic circuit is formed across the magnetizable outer wall and passes through the shoe or slider. The mover has a coil in which a current can be induced from the closed magnetic circuit.

Description

[Technical field]

[0001] Related Applications This application claims the benefit of priority under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 62 / 982,085, filed February 27, 2020, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] The present invention relates generally to a system for supplying power from a power source to an electrical load, particularly when there is relative motion between the power source and the load, and more specifically to an improved non-contact power supply system for motion devices, for example when the motion is linear rather than rotational, or linear in addition to rotational, and further when precision motion is required.

[0003] Linear motion electric systems are particularly applicable in industrial automation systems. Such systems usually include a moving element that is used to transport the product parts to one or more stations. At each station a specific manufacturing process is applied to the product parts. Modern automation systems use very fast and precise transport systems in order to reduce the production and transport times to the achievable minimum. For that purpose they use very precise positioning systems. The product parts to be processed are placed on a moving carriage that is driven by the positioning system.

[0004] Power often needs to be available to the moveable carriage to operate the various sensors and activators. In a first example, the moveable carriage is attached to a linear motor where the motor is part of the track or moved by a motor fixed to the carriage. In another example, a position encoder is needed to control the position of the carriage, and the position encoder and / or the carriage generally require a power source. In another example, a rotary table may be needed to orient the product part in a desired direction so that there is both rotary and linear motion.

[0005] To provide power to the moving carriage, flexible cables are commonly used and may be arranged in cable chains. Whenever high speed movements are required, these cable assemblies induce vibrations that adversely affect the movement of the carriage and are prone to failure. In some systems, sliding brushes are used to transmit the electrical energy. Brushes have a limited life span and generate electrical noise, limiting their use to relatively low speed systems.

[0006] Cable chains and brushes can add cost and reduce system reliability. It is therefore desirable to provide a system capable of providing power to a moveable carriage that is contactless and does not require either brushes or flexible moving cables.

[0007] Patent No. 5,341,280 by Divan et al. discloses such a contactless power transfer system, which does not involve friction or movement of flexible cables. A high intensity AC current is passed through a static conductor, a magnetic core is fixed to the slide of a moving element, and the moving element can collect power by induction, as the moving element slides along the static conductor. The drawback of this solution is that the magnetic core used to collect the energy is relatively heavy, reducing the maximum achievable acceleration of the carriage. Summary of the Invention

[0008] A system according to this embodiment includes a stator portion and at least one mover.

[0009] In the stator, a long hollow profile of ferromagnetic material is placed along a desired linear path. The linear path can be any closed or open shape. The cross section of the long profile preferably has a rectangular shape, with an opening on the upper side, preferably in a central position. Two electrical conductors of substantial cross-sectional size extend inside the hollow profile, on either side of the opening. A high-intensity alternating current (AC) current flows in these two conductors in opposite directions or in antiphase.

[0010] The mover, movable along a path, includes a core made of ferromagnetic material around which the coil is wound. The core profile is inserted into an opening in the profile and slides along the path without contacting the stator profile. As the mover slides along the path, the core closes two magnetic circuits with a small air gap around the stator conductors on either side of the core. The magnetic flux induced in these magnetic circuits crosses the mover coils in the core and induces electrical power in the mover coils. Electrical power is then available at the mover without electrical contact between the mover and the stator.

[0011] In accordance with an embodiment of the present invention, a non-contact electric motion device may be provided in which power is made available from a stationary part to a moving part in a non-contact manner, the device comprising: a stator, a cross section of the stator including a magnetizable outer wall surrounding at least two conductors and a hollow space, the magnetizable outer wall having a discontinuity forming at least one air gap, the discontinuity separating the stator into two stator halves, the stator in longitudinal cross section and the hollow space forming a rail; and a mover having a first portion configured to fit within the hollow space and travel along the rail, the mover substantially closing the air gap at any given location as it passes through each of the stator halves and the first portion to form a closed magnetic circuit across the magnetizable outer wall, the mover including a coil through which a current can be induced from the closed magnetic circuit.

[0012] In one embodiment, at least two conductors are each located in each half of the stator, the conductors being configured to each carry an alternating current in antiphase.

[0013] In one embodiment, the mover is configured to move along the stator to successive positions along the stator to form a closed magnetic circuit, with an open magnetic circuit at other positions of the plurality of positions.

[0014] In one embodiment, the length of the air gap extends longitudinally along the stator.

[0015] In one embodiment, the height of the gap is the thickness of the magnetizable outer wall.

[0016] In one embodiment, the closed magnetic circuit includes two closed magnetic circuits and two air gaps, each closed magnetic circuit extending around one half of the stator, then through a first portion of the air gap, to a first portion of the mover, then through a second portion of the air gap, and back to the stator half, the mover filling both of the air gaps at the mover's current position.

[0017] In one embodiment, the mover includes at least one wheel, or one wheel and one slider, or two wheels or two sliders, or three or more wheels, or other combinations of wheels and sliders.

[0018] In one embodiment, the mover comprises a motor, the motor being powered from a current induced in a coil.

[0019] In one embodiment, multiple movers are inserted into a single stator.

[0020] In one embodiment, each mover includes a motion or position sensor and is wirelessly controlled from a central controller to move along the stator based on feedback from the sensors.

[0021] In one embodiment, the stator is a gantry bridge and the mover is attached to the gantry bridge.

[0022] According to a second aspect of the present invention, there is provided a contactless electric motion device comprising a rail and a mover, the rail being hollow and having an open gap, the mover having a shoe fitting within the hollow and a neck extending through the open gap, the mover configured to travel along the rail, the rail surrounding at least one current carrying conductor and being magnetizable, the mover also being magnetizable and closing the open gap as it passes and forming a magnetic circuit throughout the shoe, the mover further including a coil around the shoe for inducing a current from the magnetic circuit, thereby providing on-board power to the mover in a contactless manner.

[0023] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, exemplary methods and / or materials are described below. In case of conflict, the patent specification, including definitions, will control. Furthermore, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

[0024] Some embodiments of the invention are described herein, by way of example only, with reference to the accompanying drawings, in which: Reference is now made in particular detail to the drawings, stressing that the particulars shown are by way of example and for the purposes of illustrative discussion of embodiments of the invention, and in this regard the description using the drawings will make apparent to those skilled in the art how embodiments of the invention may be practiced. [Brief description of the drawings]

[0025] [Figure 1] A drawing in Figure 4 of prior art Patent No. 5,341,280 to Divan et al. is provided for reference. [Diagram 2] FIG. 1 is a simplified schematic perspective view according to an embodiment of the present invention. [Diagram 3] 3 is a simplified cross-sectional view of the embodiment of FIG. 2 taken along the plane defined by line A in FIG. 2. [Figure 4]3 is a simplified cross-sectional view of the embodiment of FIG. 2 taken along the plane defined by line B in FIG. 2. [Diagram 5] FIG. 1 is a simplified schematic diagram of a multi-carriage system with several carriages on one closed-loop stator and contactless power collection according to an embodiment of the invention. [Figure 6] 1 is a simplified schematic cross-sectional view of a transformer used to drive high current strengths in stator conductors in accordance with an embodiment of the present invention. [Figure 7] FIG. 7 is a simplified schematic diagram showing how a high power drive is used to drive current through the primary of the transformer shown in FIG. 6, and also shows how high intensity currents are driven through the stator conductors by the secondary of that transformer. [Figure 8] FIG. 1 is a simplified schematic diagram of a common type of overhead crane using a moving electric cable. [Figure 9] FIG. 1 is a schematic diagram of an overhead crane implemented in accordance with an embodiment of the present invention without moving electrical cables. [Figure 10] 4 is a simplified cross-sectional schematic diagram of a stator and a mover according to a further embodiment of the present invention; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The present invention relates generally to systems for supplying electrical power from a power source to an electrical load, particularly when there is relative motion between the power source and the load, and more specifically to an improved non-contact power supply system, for example when the motion is linear rather than rotational, or linear in addition to rotational, and further when precision motion is required.

[0027] An embodiment of the present invention may provide a contactless electric motion device in which power is made available contactlessly from a stationary part to a moving part. A stator, the cross section of which includes a magnetizable outer wall, encloses a conductor and a hollow space, the magnetizable outer wall having discontinuities that form an air gap. The stator and hollow space in longitudinal cross section form a rail. The moving part has a shoe or slider that fits within the hollow space to travel along the rail, the moving part filling the air gap contactless at any given location as it passes. The term "contactless filling" means that the material of the moving part fills the air gap until it is almost in contact with the wall of the stator, but does not actually make contact, leaving a fairly small air gap. However, the aspect ratio of the air gap is altered to significantly lower the magnetic resistance, and a viable magnetic circuit is formed. When the air gap is effectively closed, a magnetic circuit is formed across the magnetizable outer wall and through the shoe or slider. The moving part has a coil in which a current can be induced from the closed magnetic circuit.

[0028] To better understand some embodiments of the present invention, reference will first be made to the structure and operation of a known device, as shown in FIG.

[0029] FIG. 1 shows the prior art described in U.S. Patent No. 5,341,280 to Divan et al. A primary transformer 38 drives current into an electrical conductor 40. The electrical conductor 40 is positioned along a travel path having turn-backs. Two magnetic cores 56 and 58 surround the current conductor in both directions and slide along the path without contacting the conductor. A winding 52 is wound around the two magnetic cores and power is available at the winding ends 46.

[0030] The magnetic core is fixed to the moving element. Following conventional design rules, the weight of the magnetic core is proportional to the power provided to the moving element. Whenever significant power is required, the maximum acceleration is limited by the design weight, which is a fraction of the weight of the moving element.

[0031] Whenever long paths are required, conductor support structures must be used. These structures may traverse the moving core, necessitating the creation of air gaps within the core. To keep the air gaps as small as possible, these structures must be designed to be thin. Divan et al. propose a design (Figures 7 and 8 of U.S. Pat. No. 5,341,280) that results in a relatively high-cost and relatively fragile structure.

[0032] In the Divan embodiment, the electrical conductor 40 is outdoors. To be fully efficient, a high frequency of current is required in the conductor 40. This high intensity, high frequency current flowing outdoors can generate strong, undesirable electrical radiation and can interfere with other nearby equipment.

[0033] In the present embodiment described herein below, a contactless power system (CPS) is described, which reduces the amount of weight added to the mover, can simplify the overall structure, and minimizes the amount of electrical radiation and therefore the range of interference.

[0034] For clarity, the following description refers to a preferred orientation of the CPS, but the CPS may be oriented in any manner suitable for the required operation.

[0035] Before describing at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of components and / or methods set forth in the following description and / or illustrated in the drawings and / or examples, as the invention is capable of other embodiments or of being practiced or carried out in various ways.

[0036] Referring to Figure 2, a simplified perspective view of one embodiment of a contactless power system (CPS) according to the present invention is shown. The CPS 200 includes a stator 201, 203a, 203b and at least one mover 202, 204, 205. The mover can slide along a defined desired path. The defined path can be, for example, linear, curved, or circular in shape.

[0037] The stator preferably comprises a long profile 201 of magnetizable material such as laminated iron or electric steel. The long profile 201 has a cross section of a rectangular hollow shape with a hollow interior enclosed within a wall and has an opening or gap 206 at its top surface, the height of the gap being the thickness of the wall. The long profile 201 may extend along the entire path of movement and define a trajectory for the movement. In FIG. 2 only a short, straight section of the stator is shown. Although a straight shape is shown in FIG. 2, it should be understood that any curved or circular shape may be used to follow the desired path of the mover.

[0038] Within the stator, two large conductors 203a and 203b are positioned on either side of the opening. Alternating current (AC) current flows in opposite directions or in antiphase in conductors 203a and 203b.

[0039] The mover includes a vertical portion or neck 204 and a horizontal portion 205, both made of a magnetic material such as laminated electrical steel. A coil may be wound around the base of the vertical portion 204 to form the shoe 202. The mover slides along a path inside an opening 206 in the long profile 201, the shoe being contained inside the stator.

[0040] Referring to FIG. 3, a cross section of the CPS of FIG. 2 is shown in the plane defined by dashed line A in FIG. 2. In this view, it can be seen how the mover core assemblies 205 and 204 create two magnetic circuits 301a and 301b. The vertical portion of the core 204 made of magnetic material provides a path for the magnetic flux. The magnetic circuit 303a extends in the magnetic material of high magnetic permeability, except for small air gaps 303a and 302, which it must cross to allow it to move freely in the stator. Symmetrically, the magnetic circuit 303b is similarly disposed in the magnetic material of high magnetic permeability, except for small air gaps 303b and 302. The current in the conductor 203a exits the cross section and creates a magnetic flux that flows in the counterclockwise direction in the magnetic circuit 301a. Symmetrically, the current in the conductor 203b enters the cross section and creates a magnetic flux that flows in the clockwise direction in the magnetic circuit 301b.

[0041] Inside the vertical part 204 of the core, both magnetic fluxes flow in the same direction, inducing power in the surrounding coil 202. Power is made available at the mover without electrical contact with the stator.

[0042] Now referring to FIG. 4, a further cross-section of the CPS of FIG. 2, this time the cross-section is in the plane defined by dashed line B of FIG. 2. The plane of the cross-section is cut at a height that does not include the mover. Due to the efficiency of the CPS, the inductance of the stator can be low. In FIG. 4, it can be seen that the long profile 201 creates a magnetic circuit 401 around the two conductors 203a and 203b. However, since the currents flowing through 203a and 203b are equal and opposite in direction or phase, the total current enclosed by the magnetic circuit 401 is zero. As a result, the magnetic flux in the circuit is zero and the inductance of the circuit formed by 203a and 203b is very low. It is therefore possible to drive large currents at relatively high frequencies in these conductors, allowing the transfer of significant power to the mover.

[0043] In another aspect, magnetic circuit 401 creates a shield around conductors 203a and 203b such that substantially no magnetic field radiates outside the CPS, thereby enabling use of the CPS in close proximity to or in combination with other systems that are sensitive to electrical interference.

[0044] Reference is now made to FIG. 5, which is a simplified diagram of a multi-carriage system 500 that may be advantageously implemented using a CPS in accordance with an embodiment of the present invention.

[0045] A CPS stator 501, including a long profile similar to profile 201 described above, and with enclosed conductors similar to conductors 203a and 203b of FIG. 2, is arranged along a closed loop path. Alternating current is driven in the stator conductors by a power supply 504. Five independent movers 501a-501d are slidably inserted along the stator 501. Each mover slides along a track defined by the stator and may be guided by bearings or wheels (not shown). As explained above, each mover collects power from the stator. Each mover is propelled by its own motor, symbolically shown as 503a-503d, which is powered using the collected power. The mover motors may be of either rotary or linear type. Each mover may also include a motor controller that controls the position of the mover, which is also powered by the CPS. In one example, the motor controllers communicate wirelessly with a central controller, and the position and speed of each mover are then controlled by the central controller.

[0046] Existing multi-carriage systems of the prior art have separate position control for each motor and utilize multiple drivers, each controlling a small portion of the stator. To control the movement of each carriage, a central controller activates the drivers for the portion of the stator proximate to the carriage. However, these existing multi-carriage systems are very expensive and require very complex software due to the large number of drives involved. The multi-carriage system powered by the CPS of the present embodiment can be implemented at a fairly low cost because the entire stator can be driven as a single unit.

[0047] To drive the high intensity AC current required for the stator conductors 203a and 203b, a transformer may be used. Referring now to FIG. 6, a cross section of such a transformer 600 is shown. The transformer 600 has a magnetic core 602 that forms two magnetic circuits 603a and 603b that enclose two open air volumes 604a and 604b. A primary coil 601 with N turns is wound around a central portion of the magnetic core that is common to both magnetic circuits. The two conductors 203a and 203b of the CPS stator extend through the remaining space of the open air volumes 604a and 604b, respectively.

[0048] Referring now to Figure 7, a transformer 600 is shown enclosed in a dashed line. Conductor 203a and conductor 203b are shown traversing the transformer, and their ends are connected by a connecting conductor 703 after traversing the transformer. A portion of the long profile of the stator is shown as 704. At this portion, the two conductors 203a and conductor 203b exit the long profile and traverse the transformer 600. After traversing the transformer 600, their ends 705a and 705b are electrically connected by conductor 703.

[0049] The other ends of conductors 203a and 203b, shown as 706a and 706b respectively, are also electrically connected by conductor 702. In Figure 7, these other ends are shown in the same part of stator 704. This is the case when the stator forms a closed circuit as in Figure 5. Whenever the stator does not form a closed circuit, connection 702 is applied to the ends of conductors 203a and 203b.

[0050] Finally, the two conductors 203a and 203b connected together at both ends constitute a single closed loop of electrical conductor extending through the transformer 600. This closed loop constitutes the one turn shorted secondary coil of the transformer 600. By transformer laws, if a current I flows through the N turn primary coil 601, a current N×I will flow through the one turn shorted secondary coil and thus through conductors 203a and 203b.

[0051] Thus, high intensity currents can be passed through stator conductors 203a and conductors 203b by transformer 600. This allows a commonly available AC power source 701 to be used to drive high intensity currents in the CPS stator conductors.

[0052] Whenever very long paths are required, the CPS stator can be divided into several sections, each section having its own power supply, as explained above with reference to Figures 6 and 7.

[0053] In another exemplary application, a CPS according to an embodiment of the present invention may be advantageously implemented on an overhead crane or overhead gantry, thus eliminating the need for moving cables.

[0054] In FIG. 8, a schematic diagram of a commonly recognized overhead gantry that can often be found in a factory setting is shown. A beam 803 is fixed to two walls 801 and 802 at both ends. A crane controller 807 includes wheels, gears, motors, and an electric controller. The crane controller 807 can slide along the beam 803 by an electric motor 804. A hook 805 suspended from the crane body is provided to secure an object to be manipulated. The vertical position of the hook is controlled by a motor 809. A hand controller 808 is provided for manual operation of the crane. A flexible cable 806 is used to connect power to the controller and the motor.

[0055] As shown diagrammatically in Fig. 8, the cable 806 is typically bent or coiled and the coil may be fixed to a slider that can slide along the beam, allowing free movement of the crane controller. Whenever the crane is used intensively, the movement of the cable 806 may suffer increased friction due to dirt accumulation on the sliding elements. Furthermore, bending and unfolding of the cable 806 due to repeated use of the crane may result in failure of the cable, resulting in damage, inoperability and dangerous operation of the crane.

[0056] In Figure 9, an implementation of a crane using a CPS according to an embodiment of the present invention is shown in schematic form. The overhead crane has the same components as shown in Figure 8, except that no cable 806 is used, the beam 903 includes a CPS stator according to an embodiment of the present invention, and a current generator 906 is added to drive the current in the CPS conductors. The crane controller is energized by the CPS and controls the movement of the crane, and the implementation of the CPS results in improved reliability and safety of the crane operation. Additionally, maintenance costs are reduced.

[0057] It will be clear to those skilled in the art that many other applications of CPSs can be devised in which power is transferred contactlessly to moving elements.

[0058] Reference is now made to Figure 10, which shows a schematic cross-sectional view of an alternative embodiment of a CPS according to the invention. The CPS 1000 comprises a stator 1003 and at least one mover 1001. The mover 1001 may be advanced on the stator 1003 by wheels 1002a-1002c. The stator extends in a direction perpendicular to the cross-section and defines a path of movement. This path may be of any curved type.

[0059] The stator comprises two long profiles 1004a-b of magnetisable material, preferably laminated iron or electric steel. The long profiles 1004a-b form rectangular hollow cavities 1006a and 1006b, respectively. These two long profiles 1004a and 1004b are arranged in the stator 1003, so that the cavities 1006a and 1006b face each other and are spaced apart to allow the movement of a short profile portion 1008 fixed to the mover. The long profiles 1006a and 1006b extend along the entire movement path of the mover, while the short profile portion 1008 fixed to the mover extends along a short path within the confines of the mover.

[0060] Inside the stator, two large conductors 1005a and 1005b are placed inside cavities 1006a and 1006b, respectively. AC currents flow in opposite phases in conductors 1005a and 1005b, respectively.

[0061] Attached to the mover is a short section of profile 1008, preferably made of laminated magnetisable material. The two long profiles 1004a and 1004b and the profile section 1008 are shaped to provide large area thin air gaps 1007a-d.

[0062] A coil 1009 is wound around the middle portion of the profile portion 1008 .

[0063] A CPS according to the embodiment of FIG. 10 functions as described below.

[0064] In the position where the mover is not present, the two long profiles 1004a and 1004b form a magnetic circuit 1011 (dotted lines in a square shape) with a large gap between them resulting in a very high magnetic resistance. Furthermore, the two currents flowing through the conductors 1005a and 1005b are in opposite directions, or in opposite phase for AC, and induce opposite magnetic fluxes in the magnetic circuit 1011, so the inductance of the stator 103 is very low and the electromagnetic radiation emitted outside the stator is negligible.

[0065] Where the mover bridges the gap, two magnetic circuits 1010a-1010b are formed around the conductor 1005a and the conductor 1005b, respectively. The two magnetic fluxes induced by the current flow in the same direction in the coil 1009, inducing power in the coil 1009. Thus, the mover is powered. For example, an electric motor can be attached to the mover to drive it. Other electric or electronic devices such as encoders, digital communication interfaces, digital inputs and outputs can be used with the mover.

[0066] The terms "comprises," "comprising," "includes," "including," "having," and their combinations mean "including but not limited to."

[0067] The term "consisting of" means "including and limited to."

[0068] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly indicates otherwise.

[0069] It is understood that certain features of the invention that are described for clarity in the context of separate embodiments may also be provided in combination in a single embodiment, and the description of the invention shall be construed as if such embodiments were expressly described herein. Conversely, various features of the invention that are described for brevity in the context of a single embodiment may also be provided separately or in any suitable subcombination, or as suitable modifications to any other described embodiment of the invention, and the description of the invention shall be construed as if such separate, subcombination, and modified embodiments were expressly described herein. Certain features described in the context of various embodiments should not be regarded as essential features of those embodiments, unless the embodiment cannot function without those elements.

[0070] While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications, and variations that fall within the spirit and broad scope of the appended claims.

[0071] All publications, patents, and patent applications mentioned in this specification are hereby incorporated by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference herein. Furthermore, citation or identification of any reference in this application should not be construed as an admission that such reference is available as prior art to the present invention. To the extent section headings are used, they should not be construed as necessarily limiting. Additionally, any priority document(s) of this application are hereby incorporated by reference in their entirety herein.

Claims

1. A non-contact electric motion device in which electric power is made available from a stationary part to a moving part in a non-contact manner, the non-contact electric motion device comprising: a stator, a cross section of the stator including a magnetizable outer wall surrounding at least two conductors and a hollow space, the magnetizable outer wall having a discontinuity forming at least one air gap, the discontinuity separating the stator into two stator halves, the stator and hollow space in a longitudinal cross section forming a rail; a mover having a first portion configured to fit within the hollow space and travel along the rail, the mover substantially closing the air gap at any given location as it passes through each of the stator halves and the first portion to form a closed magnetic circuit across the magnetizable outer wall, the mover including a coil through which a current can be induced from the closed magnetic circuit; A non-contact electric exercise device comprising:

2. The non-contact electromotion device of claim 1 , wherein the at least two conductors are each located in a respective half of the stator, the conductors being configured to each carry alternating current in antiphase.

3. 3. The non-contact electric motion device of claim 2, wherein the mover is configured to move along the stator to successive positions along the stator to form the closed magnetic circuit, and at other of the positions there is an open magnetic circuit.

4. The non-contact electric motion device of any one of claims 1 to 3, wherein the length of the air gap extends longitudinally along the stator.

5. The non-contact electrokinetic device of claim 4 , wherein the height of the air gap is the thickness of the magnetizable outer wall.

6. 6. The non-contact electric motion device of claim 1, wherein the closed magnetic circuit includes two closed magnetic circuits and two air gaps, each closed magnetic circuit extending around one half of the stator, then through a first portion of the air gap, to the first portion of the mover, then through a second portion of the air gap, and back to the one half of the stator, the mover filling both of the air gaps at the current position of the mover.

7. The non-contact electric motion device of any one of claims 1 to 6, wherein the mover comprises at least one wheel.

8. The non-contact electric motion device of claim 1 , wherein the mover includes a motor, the motor being powered by the current induced in the coil.

9. The non-contact electric motion device according to any one of claims 1 to 8, wherein a plurality of movers are inserted into a single stator.

10. 10. The non-contact electric motion device of claim 9, wherein each mover includes a motion or position sensor and is wirelessly controlled from a central controller to move along the stator based on feedback from the sensors.

11. The non-contact electric motion device of any one of claims 1 to 10, wherein the stator is a gantry bridge, and the mover is attached to the gantry bridge.

12. 1. A non-contact electric motion device comprising a rail and a mover, the rail being hollow and having an open gap, the mover having a shoe that fits within the hollow and a neck that extends through the open gap, the mover configured to travel along the rail, the rail surrounding at least one current carrying conductor and being magnetizable, the mover also being magnetizable, closing the open gap as it passes and forming a magnetic circuit throughout the shoe, the mover further including a coil around the shoe to induce a current from the magnetic circuit, thereby providing on-board power to a moving part in a non-contact manner.

Images