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Linear reluctance motorLinear reluctance motor description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070182256, Linear reluctance motor. Brief Patent Description - Full Patent Description - Patent Application Claims
RELATED APPLICATIONS [0001] This application is a continuation of prior U.S. patent application Ser. No. 10/726,420 filed Dec. 3, 2003 (which is incorporated herein by reference) which claims the benefit of and priority to Provisional Patent Application Ser. No. 60/431,604 filed Dec. 6, 2002. FIELD OF THE INVENTION [0002] This invention relates to a linear reluctance motor. BACKGROUND OF THE INVENTION [0003] Conventional electric motors, both rotary and linear, have very poor torque and force density. For heavy lifting applications, mechanical means such as gears and screws are more typically used. Fluidic devices including pneumatic and hydraulic systems are also used. These mechanical methods generally involve noise, wear, backlash, poor shock tolerance, and high reflected inertia. The fluidic methods tend to increase system complexity due to the addition of a fluid system. Fluid systems are also harder to control than electric systems. Due to seal wear, the fluid methods are unreliable and can contaminate sensitive environments when the working fluid leaks. [0004] A polyphase disc reluctance rotary motor is shown in U.S. Pat. No. 3,992,641 incorporated herein by this reference. [0005] Most prior art linear motors operating on the principle of magnetism, however, include permanent magnets or are classified as inductance machines. U.S. Pat. No. 4,864,169, also incorporated herein by this reference, discloses a linear reluctance motor but it is configured such that the magnetic flux produced extends in the direction of the actuation axis. Such a design, however, results in a fairly low force density. [0006] Thus, there exists a need for a high force density linear reluctance motor. SUMMARY OF THE INVENTION [0007] It is therefore an object of this invention to provide a linear reluctance motor. [0008] It is a further object of this invention to provide such a linear reluctance motor which exhibits a high force density. [0009] It is a further object of this invention to provide such a linear reluctance motor which can be configured into a number of different designs depending on the specific application. [0010] The invention results from the realization that a better linear reluctance motor is effected by orienting the windings of the coils to produce flux through a set of interleaved blades of the stator and shuttle in a direction substantially transverse to the actuation axis. Also, by making the blades relatively thin, the blade density can be increased resulting in a large force density. The conventional wisdom is that each blade must be sufficiently thick and stiff to support itself and/or that the gaps between the blades must be large. The truth is that in a relatively slow moving motor, the blades can actually touch and rub against each other. With smaller gaps between the blades, there is less attractive force between the blades resulting less friction. And, the added benefit of reducing the extent of the gaps between the blades is reduced losses and less coil current required to generate the necessary flux. [0011] This invention features a linear reluctance motor having an actuation axis, the linear reluctance motor comprising a stator including a set of spaced blades each extending in the direction of the actuation axis, each blade including a plurality of alternating low permeability and high permeability teeth, a shuttle also including a set of spaced blades each extending in the direction of the actuation axis interleaved with the blades of the stator, each blade of the shuttle also including a plurality of alternating low permeability and high permeability teeth, and an active component associated with either the stator, the shuttle, or both, the active component divided into at least N phases, each phase including a set of blades, a flux return portion, and a coil wound to produce flux through the sets of interleaved blades in a direction substantially transverse to the actuation axis. Typically, N is at least three. [0012] In one example, the stator defines a housing with a channel for receiving the shuttle therein. The channel may be C-shaped or the channel may be fully enclosed. In another example, the shuttle is telescopingly received in the stator. [0013] The phases may be in series along the actuation axis or arranged laterally with respect to the actuation axis or arranged both axially and laterally with respect to the actuation axis. [0014] There may be a large gap between the interleaved blades or a small gap between the interleaved blades. [0015] In one particular embodiment, the active component is associated with the stator and the phases are in series along the actuation axis. In this example, the stator defines a housing with a channel for receiving the shuttle therein, the blades of the shuttle extend into the channel and the blades of the stator are interleaved with the blades of the shuttle. The shuttle includes a blade carrier disposed outside the channel. A bearing assembly may be located between the blade carrier and the stator housing. There may be a large gap between the outermost blades of the shuttle and the stator housing. The large gap may be effected by tapered side walls of the shuttle housing. Alternately, the blades of the stator and the blades of the shuttle are flexible and closely spaced or the blades of the shuttle are flexible and closely spaced to the blades of the stator. [0016] In one particular example, the blades of the shuttle have a thinned blade root. In another example, the blades of the shuttle have a slotted blade root. [0017] In another particular embodiment, the active component is associated with the stator which has, for each phase, an opposing set of blades, a coil therebetween, and a flux return plate. In this embodiment, the phases are arranged in series along the actuation axis. The stator includes a housing surrounding the blades and the flux return plates and the shuttle includes a housing telescopingly received in the stator housing. [0018] In another particular embodiment, the active component is associated with the shuttle and the phases are arranged in series along the actuation axis. The stator defines a housing with a channel for receiving the shuttle therein, the blades of the stator extend into the channel, and the blades of the shuttle are interleaved with the blades of the stator. The stator housing includes a longitudinal slot and the shuttle includes a fin extending through the slot connected to a driving element located outside the channel. [0019] In another particular embodiment, the active component is associated with the stator and the phases are arranged laterally. The stator defines a housing with a channel for receiving the shuttle therein, the blade sets of the stator are adjacent each other across the channel, and the blade sets of the shuttle are adjacent each other across the channel. The blade sets of the shuttle extend into the channel from a carrier. A sliding shutter may be attached to the carrier for sealing the channel of the stator. In another particular embodiment, the active component is associated with the shuttle which includes phases distributed axially and laterally. The stator includes a housing defining a channel therein, and at least a pair of adjacent blade sets opposing another pair of adjacent blade sets. The shuttle includes at least a first pair of adjacent blade sets opposing a second pair of adjacent blade sets defining two phases and a third pair of adjacent blade sets opposing a fourth pair of adjacent blade sets defining two additional phases. [0020] In other embodiments, the active component is associated with the shuttle which travels within the stator and connected to a carriage external to the stator by a cable and pulley subsystem. The stator may be active and include phases in series along the actuation axis and the shuttle is telescopingly received in the stator. In one example, the stator has a set of opposing outwardly extending blades for each phase and the shuttle has a sets a set of opposing inwardly extending blades. Continue reading about Linear reluctance motor... Full patent description for Linear reluctance motor Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Linear reluctance motor patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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