Linear motor

Abstract

The present invention discloses a linear motor, which includes a stator assembly; an armature that can be mechanically coupled to a specimen and is configured to move relative to the stator assembly through the operation of the linear motor; and a suspension system that is configured to facilitate the movement of the armature relative to the stator assembly along a movement axis without physically contacting the armature during movement. Also disclosed are a multi-phase linear motor, a linear motor having an armature including a flat magnet array, and a linear motor having a magnetic damping system.

Description

[0001] Related Applications

[0002] This application is a non - provisional patent application claiming priority to U.S. Provisional Patent Application 62 / 795,273, filed on January 22, 2019, entitled "Linear Motor", which is incorporated herein by reference. Technical Field

[0003] The present invention generally relates to material testing systems. More particularly, the present invention relates to linear motors for material testing systems. Background Art

[0004] Linear motors are commonly used in material testing systems. In these material testing systems, it is known that a linear motor uses electricity and magnetic force to generate a reciprocating movement in an armature, which can be coupled to a specimen. The moving assembly can be "frictionless" as it can be arranged and constructed to operate without sliding or rolling contact between the armature and the armature's suspension system. Flexure suspension structures for driving the armature are known, such as the suspension structures described in U.S. Patent 6,405,599. These flexible suspension structures to which the armature is directly physically attached limit the movement of the armature based on the material properties and bendable nature of the flexure suspension structure - the more the armature moves from its central position due to electromagnetic force, the greater the resistance on the armature from the flexure suspension structure.

[0005] Accordingly, a linear motor having frictionless characteristics and its associated methods of use and assembly would be well received in the art. Summary of the Invention

[0006] In one exemplary embodiment, a testing device includes: a linear motor including a stator assembly; an armature capable of being mechanically coupled to a specimen, the armature being configured to move relative to the stator assembly by operation of the linear motor; and a suspension system configured to facilitate movement of the armature relative to the stator assembly along a movement axis without physically contacting the armature during movement.

[0007] In addition or alternatively, the suspension system of the testing device includes at least one air bushing configured to allow the armature to move relative to the suspension system without sliding or rolling contact between the armature and the suspension system.

[0008] In addition or alternatively, the suspension system of the testing device includes a frame body having a first opening extending along a first axis parallel to the movement axis, wherein at least one air bushing is located within the first opening, and wherein the armature includes a first air bushing shaft extending within the first opening.

[0009] In addition or alternatively, at least one air bushing of the test device includes a first air bushing and a second air bushing, the first air bushing being positioned near a first end of the first opening, and the second air bushing being positioned near a second end of the first opening.

[0010] In addition or alternatively, the frame body of the test device includes a second opening extending along a second axis parallel to the movement axis, and wherein the armature includes a second air bushing shaft extending within the second opening, wherein the second opening includes a third air bushing and a fourth air bushing, the third air bushing being positioned near a first end of the second opening, and the fourth air bushing being positioned near a second end of the second opening.

[0011] In addition or alternatively, at least one air bushing of the test device is mounted in the first opening of the frame body in a compliant manner such that some movement between the air bushing and the frame body is allowed.

[0012] In addition or alternatively, at least one air bushing of the test device is removably attached in the first opening of the frame body by an interference fit.

[0013] In addition or alternatively, at least one air bushing of the test device has a hollow cylindrical shape, and wherein the first air bushing shaft is a cylindrical shaft having a radius that is 3 to 5 micrometers smaller than the inner radius of the at least one air bushing.

[0014] In addition or alternatively, the stator assembly of the test device includes a first coil subassembly and a second coil subassembly, wherein the armature is located between and extends between the first coil subassembly and the second coil subassembly, the armature including a magnet frame having a plurality of permanent magnets disposed thereon, wherein the first air bushing shaft extends parallel to the magnet frame, and wherein the top plate and the bottom plate connect the first air bushing shaft and the second air bushing shaft to the magnet frame such that a first space extends parallel to the movement axis between the first air bushing shaft and the magnet frame, and such that a second space extends parallel to the movement axis between the second air bushing shaft and the magnet frame, the test device further including a piping system configured to use an air flow passing through at least one air bushing to cool at least one of the coils of the first coil subassembly and the second coil subassembly and the armature.

[0015] In addition or alternatively, the armature of the test device includes a specimen shaft extending from at least one of the top plate and the bottom plate, and wherein a fifth air bushing surrounds the specimen shaft.

[0016] In another exemplary embodiment, a linear motor includes a stator assembly configured to receive power; an armature positioned adjacent to the stator assembly and configured to move relative to the stator assembly when the stator assembly receives power; and a suspension system configured to facilitate movement of the armature relative to the stator assembly along a movement axis without physically contacting the armature during movement.

[0017] In addition or alternatively, the suspension system of the linear motor includes at least one air bushing configured to allow the armature to move relative to the suspension system without sliding or rolling contact between the armature and the suspension system.

[0018] In addition or alternatively, the suspension system of the linear motor includes a frame body having a first opening extending along a first axis parallel to the movement axis, wherein at least one air bushing is located within the first opening, and wherein the armature includes a first air bushing shaft extending within the first opening.

[0019] In addition or alternatively, at least one air bushing of the linear motor includes a first air bushing and a second air bushing, the first air bushing being positioned adjacent a first end of the first opening and the second air bushing being positioned adjacent a second end of the first opening.

[0020] In addition or alternatively, the frame body of the linear motor includes a second opening extending along a second axis parallel to the movement axis, and wherein the armature includes a second air bushing shaft extending within the second opening, wherein the second opening includes a third air bushing and a fourth air bushing, the third air bushing being positioned adjacent a first end of the second opening and the fourth air bushing being positioned adjacent a second end of the second opening.

[0021] In addition or alternatively, at least one air bushing of the linear motor is mounted within the first opening of the frame body in a compliant manner such that some movement between the air bushing and the frame body is permitted.

[0022] In addition or alternatively, at least one air bushing of the linear motor is removably attached within the first opening of the frame body by an interference fit.

[0023] In addition or alternatively, at least one air bushing of the linear motor has a hollow cylindrical shape, and wherein the first air bushing shaft is a cylindrical shaft having a radius that is 3 to 5 micrometers less than the inner radius of the at least one air bushing.

[0024] In addition or alternatively, the stator assembly of the linear motor includes a first coil sub-assembly and a second coil sub-assembly, wherein the armature is located between the first coil sub-assembly and the second coil sub-assembly and extends between the first coil sub-assembly and the second coil sub-assembly. The armature includes a magnet frame having a plurality of permanent magnets disposed thereon. A first air bushing shaft extends parallel to the magnet frame, and a top plate and a bottom plate connect the first air bushing shaft and the second air bushing shaft to the magnet frame such that a first space extends parallel to the movement axis between the first air bushing shaft and the magnet frame, and a second space extends parallel to the movement axis between the second air bushing shaft and the magnet frame. The linear motor further includes a duct system configured to use an air flow passing through at least one air bushing to cool at least one of the coils of the first coil sub-assembly and the second coil sub-assembly and the armature.

[0025] In another exemplary embodiment, a method includes: providing a stator assembly, an armature adjacent to the stator assembly, and a suspension system; receiving power by the stator assembly; after receiving power by the stator assembly, moving the armature back and forth along a movement axis relative to the stator assembly; and supporting the armature with the suspension system without physically contacting the armature during movement.

[0026] In another exemplary embodiment, a test device includes a polyphase linear motor. The polyphase linear motor includes a stator assembly; an armature that can be mechanically coupled to a specimen and is configured to move relative to the stator assembly by operation of the polyphase linear motor; and a suspension system configured to support the armature and control the movement of the armature relative to the stator assembly, wherein the suspension system is constructed to operate without sliding or rolling contact between the armature and the suspension system.

[0027] In addition or alternatively, the polyphase linear motor of the test device is a three-phase linear motor.

[0028] In addition or alternatively, the stator assembly of the test device includes a first coil sub-assembly and a second coil sub-assembly, wherein the armature is located between the first coil sub-assembly and the second coil sub-assembly and extends between the first coil sub-assembly and the second coil sub-assembly. The armature includes a plurality of permanent magnets disposed thereon.

[0029] In addition or alternatively, the first coil sub-assembly of the test device is a laminated core including a plurality of magnetic poles, and a plurality of vertically disposed windings are wound around the plurality of magnetic poles to form a first coil stack. And the second coil sub-assembly is a laminated core including a plurality of magnetic poles, and a plurality of vertically disposed windings are wound around the plurality of magnetic poles to form a second coil stack.

[0030] In addition or alternatively, the core of the first coil assembly of the test device includes six magnetic poles and six vertically arranged windings, and the core of the second coil assembly includes six magnetic poles and six vertically arranged windings, and the top winding and the fourth winding of each of the first coil stack and the second coil stack are connected to the first phase of the three-phase linear motor, the second winding and the fifth winding of each of the first coil stack and the second coil stack are connected to the second phase of the three-phase linear motor, and the third winding and the sixth winding of each of the first coil stack and the second coil stack are connected to the third phase of the three-phase linear motor.

[0031] In addition or alternatively, a gap is located between each of the plurality of vertically arranged windings of the first coil stack and the second coil stack of the test device, and the material testing device further includes at least one cooling duct configured to provide cooling air through the gap located between each of the plurality of vertically arranged windings of the first coil stack and the second coil stack.

[0032] In addition or alternatively, each of the plurality of magnetic poles of the test device includes a coil bobbin having integrated cooling fins disposed thereon, and these integrated cooling fins extend through the windings and into the gaps between the windings.

[0033] In addition or alternatively, the test device further includes potting material located within each of the gaps in the gap, and at least one heat dissipation tube embedded within the potting material of each of the gaps in the gap, and these heat dissipation tubes are configured to transfer heat from the plurality of vertically arranged windings of the first coil stack and the second coil stack.

[0034] In addition or alternatively, the test device further includes at least one cooling fin attached to each of the heat dissipation tubes, and the at least one cooling fin is configured to facilitate heat transfer.

[0035] In addition or alternatively, the stroke of the armature of the test device is at least 70 mm.

[0036] In addition or alternatively, the suspension system of the test device includes a first side frame and a second side frame configured to support the armature, and each of the first coil assembly and the second coil assembly is located between the first side frame and the second side frame, and the suspension system further includes top mounting plates for attaching to the first side frame and the second side frame and each of the first coil assembly and the second coil assembly, and the suspension system is further attached to the first side frame and the second side frame and each of the first coil assembly and the second coil assembly.

[0037] In addition or alternatively, the first side frame and the second side frame of the test device each have an I-shaped cross-section, wherein a first cooling duct is attached to the first side frame such that the space between the top and bottom on the first side of the I-shaped cross-section of the first side frame defines an air passage, wherein a second cooling duct is attached to the first side frame such that the space between the top and bottom on the second side of the I-shaped cross-section of the first side frame defines an air passage, wherein a third cooling duct is attached to the second side frame such that the space between the top and bottom on the first side of the I-shaped cross-section of the second side frame defines an air passage, and wherein a second cooling duct is attached to the second side frame such that the space between the top and bottom on the second side of the I-shaped cross-section of the second side frame defines an air passage.

[0038] In another exemplary embodiment, a linear motor includes a multiphase stator assembly including at least one stack having a plurality of cores; an armature that is close to the multiphase stator assembly and is configured to move relative to the multiphase stator assembly when power is supplied to the multiphase stator assembly; and a suspension system that is configured to support the armature and control the movement of the armature relative to the multiphase stator assembly, wherein the suspension system is configured to operate without sliding or rolling contact between the armature and the suspension system.

[0039] In addition or alternatively, the linear motor is a three-phase linear motor, and wherein the multiphase stator assembly is a three-phase stator assembly.

[0040] In addition or alternatively, the multiphase stator assembly of the linear motor includes a first coil sub-assembly and a second coil sub-assembly, wherein the armature is located between the first coil sub-assembly and the second coil sub-assembly and extends between the first coil sub-assembly and the second coil sub-assembly, and the armature includes a plurality of permanent magnets disposed thereon.

[0041] In addition or alternatively, the first coil sub-assembly of the linear motor is a laminated core including a plurality of magnetic poles, and a plurality of vertically disposed windings are wound around the plurality of magnetic poles to form a first coil stack, and wherein the second coil sub-assembly is a laminated core including a plurality of magnetic poles, and a plurality of vertically disposed windings are wound around the plurality of magnetic poles to form a second coil stack.

[0042] In addition or alternatively, the core of the first coil assembly of the linear motor includes six magnetic poles and six vertically arranged windings, and the core of the second coil assembly includes six magnetic poles and six vertically arranged windings, and the top winding and the fourth winding of each of the first coil stack and the second coil stack are connected to the first phase of the three-phase linear motor, the second winding and the fifth winding of each of the first coil stack and the second coil stack are connected to the second phase of the three-phase linear motor, and the third winding and the sixth winding of each of the first coil stack and the second coil stack are connected to the third phase of the three-phase linear motor.

[0043] In addition or alternatively, a gap is located between each of the plurality of vertically arranged windings of the first coil stack and the second coil stack of the linear motor, and the material testing device further includes at least one cooling duct configured to provide cooling air through the gap located between each of the plurality of vertically arranged windings of the first coil stack and the second coil stack.

[0044] In addition or alternatively, the stroke of the armature of the linear motor is at least 70 mm.

[0045] In addition or alternatively, a method includes: providing a linear motor having a multiphase stator assembly, an armature adjacent to the multiphase stator assembly, and a suspension system; receiving power by the multiphase stator assembly; moving the armature back and forth relative to the multiphase stator assembly along a moving axis after receiving power by the multiphase stator assembly; and supporting the armature by the suspension system by controlling the movement of the armature relative to the multiphase stator assembly such that no sliding or rolling contact occurs between the armature and the suspension system.

[0046] In another exemplary embodiment, a testing device includes a linear motor including a stator assembly; an armature that can be mechanically coupled to a specimen and is configured to move relative to the stator assembly by operation of the linear motor, the armature including an array of flat magnets configured to generate movement in the armature in response to a magnetic field generated by the stator assembly; and a suspension system configured to support the armature and control the movement of the armature relative to the stator assembly, wherein the suspension system is configured to operate without sliding or rolling contact between the armature and the suspension system.

[0047] In addition or alternatively, the armature of the testing device includes a magnet frame having a plurality of permanent magnets disposed therein such that the plurality of magnets are exposed from a first side of the armature and a second side of the armature opposite the first side.

[0048] In addition or alternatively, the array of the testing device includes two columns of flat sheet magnets arranged with alternating polarities.

[0049] In addition or alternatively, the flat sheet magnets of each of the first and second arrays of the test device are attached to the armature in a skewed manner such that the bottom and top edges of each magnet in the flat sheet magnets are not orthogonal to the side edges of the flat sheet magnets.

[0050] In addition or alternatively, each of the two columns of the arrays of the test device includes fourteen flat sheet magnets.

[0051] In addition or alternatively, the stator assembly of the test device includes a first coil subassembly and a second coil subassembly, wherein the armature is located between and extends between the first coil subassembly and the second coil subassembly, wherein the first coil subassembly includes a plurality of magnetic poles, and a plurality of vertically arranged windings are wound around the plurality of magnetic poles to form a first coil stack, and wherein the second coil subassembly includes a plurality of magnetic poles, and a plurality of vertically arranged windings are wound around the plurality of magnetic poles to form a second coil stack.

[0052] In addition or alternatively, the flat magnet array extends along the armature of the test device by a first length that is greater than a second length of each of the first and second coil stacks.

[0053] In addition or alternatively, the armature of the test device includes a magnet frame that has a first side face close to the first coil assembly, the magnet frame has a second side face opposite to the first side face and close to the second coil assembly, the armature further includes a first bushing shaft, a second bushing shaft, a top end plate, and a bottom end plate, wherein the top end plate and the bottom end plate connect the first bushing shaft and the second bushing shaft to the magnet frame such that a first space extends between the first bushing shaft and the magnet frame parallel to the movement axis, and such that a second space extends between the second air bushing shaft and the magnet frame parallel to the movement axis.

[0054] In addition or alternatively, the stroke of the armature of the test device is at least 70 mm.

[0055] In addition or alternatively, each flat magnet in the flat magnets of the test device includes a thickness between 10 mm and 22 mm, and each flat magnet in the flat magnets is a permanent magnet.

[0056] In another exemplary embodiment, a linear motor includes a stator assembly configured to receive power; an armature mechanically coupleable to a specimen, the armature configured to move relative to the stator assembly when the stator assembly receives power, the armature including an array of flat magnets configured to generate movement in the armature in response to a magnetic field generated by the stator assembly; and a suspension system configured to support the armature and control movement of the armature relative to the stator assembly. The suspension system is configured to operate without sliding or rolling contact between the armature and the suspension system.

[0057] In addition or alternatively, the armature of the linear motor includes a magnet frame having a plurality of permanent magnets disposed therein such that the plurality of magnets are exposed from a first side of the armature and a second side of the armature opposite the first side.

[0058] In addition or alternatively, the array of linear motors includes two columns of flat sheet magnets arranged in alternating polarities.

[0059] In addition or alternatively, the flat sheet magnets of each of the first and second arrays of the linear motor are attached to the armature in a skewed manner such that the bottom and top edges of each magnet in the flat sheet magnets are not orthogonal to the side edges of the flat sheet magnets.

[0060] In addition or alternatively, each of the two columns of the array of linear motors includes fourteen flat sheet magnets.

[0061] In addition or alternatively, the stator assembly of the linear motor includes a first coil subassembly and a second coil subassembly, wherein the armature is located between and extends between the first coil subassembly and the second coil subassembly, wherein the first coil subassembly includes a plurality of magnetic poles with a plurality of vertically disposed windings wound around the plurality of magnetic poles to form a first coil stack, and wherein the second coil subassembly includes a plurality of magnetic poles with a plurality of vertically disposed windings wound around the plurality of magnetic poles to form a second coil stack.

[0062] In addition or alternatively, the array of flat magnets extends a first length along the armature of the linear motor, the first length being greater than a second length of each of the first coil stack and the second coil stack.

[0063] In addition or alternatively, the armature of the linear motor includes a magnet frame having a first side face close to the first coil assembly, the magnet frame having a second side face opposite to the first side face and close to the second coil assembly. The armature further includes a first bushing shaft, a second bushing shaft, a top plate and a bottom plate, wherein the top plate and the bottom plate connect the first bushing shaft and the second bushing shaft to the magnet frame, such that a first space extends between the first bushing shaft and the magnet frame parallel to the movement axis, and such that a second space extends between the second air bushing shaft and the magnet frame parallel to the movement axis.

[0064] In addition or alternatively, the stroke of the armature of the linear motor is at least 70 mm.

[0065] In another exemplary embodiment, a method includes: providing a stator assembly, an armature having a flat magnet array disposed thereon close to the stator assembly, and a suspension system; receiving power by the stator assembly; exposing the flat magnet array to a magnetic field generated by the stator assembly; generating a reciprocating movement of the armature relative to the stator assembly through the flat magnet array; and supporting the armature with the suspension system by controlling the movement of the armature relative to the poly-phase stator assembly such that no sliding or rolling contact occurs between the armature and the suspension system.

[0066] In another exemplary embodiment, a test device includes: a linear motor including a stator assembly; an armature that can be mechanically coupled to a specimen and is configured to move relative to the stator assembly through the operation of the linear motor; a suspension system configured to support the armature and control the movement of the armature relative to the stator assembly, wherein the suspension system is constructed to operate without sliding or rolling contact between the armature and the suspension system; and a magnetic damping system configured to absorb the kinetic energy of the movement of the armature when power to the linear motor is cut off.

[0067] In addition or alternatively, the magnetic damping system of the test device includes a magnet array disposed on the frame of the suspension system parallel to the movement axis of the armature, wherein the magnet array is configured to absorb the kinetic energy of the movement of the armature when power to the linear motor is cut off, and wherein the magnet array is configured to provide damping during the operation of the linear motor to enhance the control of the movement of the armature.

[0068] In addition or alternatively, the magnet array of the magnetic damping system of the test device is separate from the magnet used to generate the movement of the armature by the linear motor, wherein the magnet array is positioned close to the conductive non-magnetic surface of the armature, and the surface extends parallel to the movement axis of the armature.

[0069] In addition or alternatively, there is a gap of less than 1 cm between the magnet array and the conductive non-magnetic surface of the armature of the test device.

[0070] Additionally or alternatively, the linear motor of the test device is a three-phase linear motor, and wherein the magnetic damping system is configured to short-circuit the power to each of the three phases simultaneously.

[0071] Additionally or alternatively, the stator assembly of the test device includes a first coil sub-assembly and a second coil sub-assembly, wherein the first coil sub-assembly includes a plurality of magnetic poles, and a plurality of vertically arranged windings are wound around the plurality of magnetic poles to form a first coil stack, and wherein the second coil sub-assembly includes a plurality of magnetic poles, and a plurality of vertically arranged windings are wound around the plurality of magnetic poles to form a second coil stack.

[0072] Additionally or alternatively, the movement of the armature of the test device relative to the first coil sub-assembly and the second coil sub-assembly immediately after the power short-circuit is configured to generate an electromagnetic force, which generates a current and a force resisting the movement of the armature.

[0073] Additionally or alternatively, the magnetic damping system of the test device includes a first magnet array, which is arranged on the frame of the suspension system parallel to the movement axis of the armature and close to the first side of the armature, and wherein the magnetic damping system includes a second magnet array, which is arranged on the frame of the suspension system parallel to the movement axis of the armature and close to the second side of the armature.

[0074] Additionally or alternatively, the first magnet array and the second magnet array of the magnetic damping system of the test device are separated from the magnets used to generate the movement of the armature by the linear motor, wherein the first magnet array is positioned close to the first conductive non-magnetic surface of the armature, which extends parallel to the movement axis of the armature, and wherein the second magnet array is positioned close to the second conductive non-magnetic surface of the armature, which extends parallel to the movement axis of the armature, and wherein the first magnet array and the second magnet array are configured to absorb the kinetic energy of the armature movement when the power to the linear motor is cut off.

[0075] Additionally or alternatively, each magnet in the magnet array of the test device is a flat sheet permanent magnet.

[0076] In another exemplary embodiment, a linear motor includes a stator assembly configured to receive power; an armature that can be mechanically coupled to a specimen, the armature being configured to move relative to the stator assembly when the stator assembly receives power; a suspension system configured to support the armature and control the movement of the armature relative to the stator assembly, wherein the suspension system is configured to operate without sliding or rolling contact between the armature and the suspension system; and a magnetic damping system configured to absorb the kinetic energy of the armature movement when the power to the linear motor is cut off.

[0077] In addition or alternatively, the magnetic damping system of the linear motor includes a magnet array that is disposed on the frame of the suspension system parallel to the moving axis of the armature, wherein the magnet array is configured to absorb the kinetic energy of the armature movement when power to the linear motor is cut off.

[0078] In addition or alternatively, the magnet array of the magnetic damping system of the linear motor is separate from the magnets used to generate armature movement through the linear motor, wherein the magnet array is positioned close to the conductive non-magnetic surface of the armature, which extends parallel to the moving axis of the armature.

[0079] In addition or alternatively, there is a gap of less than 1 cm between the magnet array and the conductive non-magnetic surface of the armature of the linear motor.

[0080] In addition or alternatively, the linear motor is a three-phase linear motor, and wherein the magnetic damping system is configured to short-circuit the power to each of the three phases simultaneously.

[0081] In addition or alternatively, the stator assembly of the linear motor includes a first coil sub-assembly and a second coil sub-assembly, wherein the first coil sub-assembly includes a plurality of magnetic poles, and a plurality of vertically arranged windings are wound around the plurality of magnetic poles to form a first coil stack, and wherein the second coil sub-assembly includes a plurality of magnetic poles, and a plurality of vertically arranged windings are wound around the plurality of magnetic poles to form a second coil stack.

[0082] In addition or alternatively, the movement of the armature of the linear motor relative to the first coil sub-assembly and the second coil sub-assembly immediately after power short-circuiting is configured to generate an electromagnetic force that generates a current and a force that resists the movement of the armature.

[0083] In addition or alternatively, the magnetic damping system of the linear motor includes a first magnet array that is disposed on the frame of the suspension system parallel to the moving axis of the armature close to the first side of the armature, and wherein the magnetic damping system includes a second magnet array that is disposed on the frame of the suspension system parallel to the moving axis of the armature close to the second side of the armature.

[0084] In addition or alternatively, the first magnet array and the second magnet array of the magnetic damping system of the linear motor are separate from the magnets used to generate armature movement through the linear motor, wherein the first magnet array is positioned close to the first conductive non-magnetic surface of the armature, which extends parallel to the moving axis of the armature, and wherein the second magnet array is positioned close to the second conductive non-magnetic surface of the armature, which extends parallel to the moving axis of the armature, and wherein the first magnet array and the second magnet array are configured to absorb the kinetic energy of the armature movement when power to the linear motor is cut off.

[0085] In another exemplary embodiment, a method includes: providing a stator assembly, an armature proximate to the stator assembly, a suspension system, and a magnetic damping system; receiving power by the stator assembly; moving the armature back and forth relative to the stator assembly along a movement axis after receiving power by the stator assembly; supporting the armature with the suspension system by controlling the movement of the armature relative to the multiphase stator assembly such that no sliding or rolling contact occurs between the armature and the suspension system; cutting off power to the stator assembly; and absorbing kinetic energy of the armature movement by the magnetic damping system when power to the linear motor is cut off. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] The above and other advantages of the present invention will be better understood by reference to the following description in conjunction with the accompanying drawings, in which like reference numerals refer to the same elements and features in each of the drawings. For clarity, not every element is labeled in each drawing. The drawings are not necessarily to scale, and emphasis is placed on illustrating the principles of the present invention.

[0087] Figure 1 A perspective view of a linear motor according to one embodiment is depicted.

[0088] Figure 2 A cross-sectional view of the linear motor taken along arrow A-A according to one embodiment is depicted. Figure 1 of the linear motor.

[0089] Figure 3 A perspective view of the linear motor according to one embodiment is depicted, in which cooling ducts are shown. Figure 1 of the linear motor.

[0090] Figure 4 A perspective view of the first side frame of the linear motor according to one embodiment is depicted. Figure 1 and Figure 3 of the linear motor, which reveals the top side.

[0091] Figure 5 A perspective view of the second side frame of the linear motor according to one embodiment is depicted. Figure 1 and Figure 3 of the linear motor, which reveals the bottom side.

[0092] Figure 6 A perspective view of the frame subassembly of the linear motor oriented to reveal the upper side according to one embodiment is depicted, the frame subassembly including a first side frame Figure 4 connected between an upper plate and a lower plate and Figure 5 a second side frame of the linear motor.

[0093] Figure 7 A perspective view of the frame subassembly of the linear motor oriented to reveal the lower side according to one embodiment is depicted. Figure 6 of the linear motor.

[0094] Figure 8 depicts a perspective sectional view of the first side frame of Figure 4 according to one embodiment, showing two air bushings disposed within a vertical opening.

[0095] Figure 9 depicts a perspective view of the armature of a linear motor of Figure 1 and Figure 3 according to one embodiment.

[0096] Figure 10 depicts a perspective view of the magnet frame of the armature of Figure 9 according to one embodiment.

[0097] Figure 11 depicts an enlarged perspective view of a portion of the magnet array of the magnet frame of Figure 10 according to one embodiment.

[0098] Figure 12 depicts a perspective view of the coil sub - assembly of the linear motor of Figure 1 and Figure 3 according to one embodiment.

[0099] Figure 13 depicts a side view of the coil sub - assembly of Figure 12 according to one embodiment.

[0100] Figure 14 depicts a perspective view of the coil former of the coil assembly of Figure 12 with integrated cooling fins according to one embodiment.

[0101] Figure 15 depicts a perspective view of the coil sub - assembly of Figure 12 with heat pipes and additional cooling fins according to one embodiment.

[0102] Figure 16 depicts the electrical schematic diagram of the three - phase motor of the linear motor of Figure 1 and Figure 3 according to one embodiment. DETAILED DESCRIPTION

[0103] Embodiments of the present invention provide many advancements in the field of test systems, and more particularly, many advancements in frictionless material handling systems. In this document, a frictionless material test system is a material test system configured to operate without contact (sliding, rolling, etc.) between: A) a moving part (such as an armature) that can be coupled to a material under test; and B) a suspension system that supports the moving part. A material test system including the frictionless material test system described herein can be configured to apply a reciprocating linear force and / or motion to a material, device, equipment, or other object under test. It has been found that frictionless material test systems have excellent reliability, sensitivity, and cleanliness compared to systems that operate with sliding or rolling contact.

[0104] Prior art frictionless material test systems have traditionally been limited in terms of stroke range because known concepts for generating controlled movement between a moving part coupled to a specimen and a suspension system require attaching a magnet carrier between flexible suspension components. When one or more magnets held by the magnet carrier are subjected to a magnetic field generated by a single-phase linear motor, the flexible suspension components will bend. This arrangement is frictionless (i.e., the bent flexible suspension components do not impart any contact-based friction), but the movement range is limited by the material properties of the flexible suspension components.

[0105] The present invention provides a frictionless material test system with an increased stroke range. The system of the present invention described herein does not require directly connecting any flexible suspension components between the armature and the suspension system. Instead, embodiments of the present invention include an armature that moves relative to a suspension system that is not directly connected to any flexible suspension supports.

[0106] Embodiments of the present invention include a material test system that includes a multi-phase linear motor having a stack of multiple cores configured to provide a desired long stroke distance. For example, the present invention includes a material test system that includes a three-phase linear motor, where each phase of the motor controls one or more windings or coils in a coil stack. The multi-phase can provide control of the armature over a greater vertical stroke distance compared to the vertical stroke distance that could be achieved with a single-phase motor.

[0107] Embodiments described herein include a frictionless material test system having an armature supported by an air bearing suspension system for controlling the movement of the armature over a large stroke distance without sliding friction. In the case where the armature is powered by a linear motor, the air bearing suspension system is configured to prevent bending or distortion of the armature caused by magnetic attraction and to maintain the distance between the armature and one or more stator components.

[0108] Embodiments of the present invention also include a frictionless material testing system having a magnetic armature for integration with a linear motor, the linear motor having a stator assembly including one or more coil stacks for moving the magnetic armature. Embodiments of the present invention include the use of an array of flat sheet magnets arranged in a skewed manner. The magnetic armature described herein also includes an array of magnets that extends through a magnet frame such that the magnets are exposed on two opposite sides or surfaces of the armature, each of the two opposite sides or surfaces being close to a corresponding stator coil stack.

[0109] A frictionless material testing system with a stopping or braking system is further described herein, the stopping or braking system including a magnetic damping system for providing damping when the frictionless material testing system stops. Embodiments include using the electromagnetic force generated by the movement of the armature of the system to generate a force that opposes the movement and slows down the armature. In embodiments using a multiphase linear motor, embodiments of the frictionless material testing system include a system configured to simultaneously cut off or short-circuit the power of each phase.

[0110] A cooling method for cooling the linear motor of a frictionless material testing system is further described. The cooling system described herein uses recirculated air supplied to the air bushings of the suspension system to cool components of the linear motor, such as windings or their coils. Other novel methods of embodiments of the cooling system of the present invention include using a coil form having fins for optimizing heat removal, and heat dissipation tubes extending from gaps between windings of the coil stack, and additional cooling fins attached to these heat dissipation tubes.

[0111] The present teachings will now be described in more detail with reference to exemplary embodiments of the present teachings as shown in the accompanying drawings. Although the present teachings are described in conjunction with various embodiments and examples, the present teachings are not intended to be limited to such embodiments. In contrast, the present teachings cover various alternatives, modifications, and equivalents, as will be understood by those skilled in the art. Those of ordinary skill in the art who can use the teachings herein will recognize additional embodiments, modifications, and implementations within the scope of the present disclosure as described herein, as well as other fields of use.

[0112] The reference to "an embodiment" or "embodiments" in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present teachings. References to particular embodiments in this specification do not necessarily all refer to the same embodiment.

[0113] Now refer to the accompanying drawings. Figure 1Depicts a perspective view of a material testing apparatus 10 including a linear motor 100 according to an embodiment. The linear motor 100 is shown as including an armature 200, a suspension system 300, and a stator assembly 400. The armature 200 includes an output shaft 210 extending from a bottom end that may be mechanically coupled to a specimen (not shown). The armature 200 and thus the output shaft 210 are configured to move back and forth along a movement axis 500 by operation of the linear motor 100, as described herein. In one embodiment, the stroke length of the armature 200 may be greater than 70 mm. In other embodiments, the stroke length of the armature 200 may be greater than 80 mm, 90 mm, or 100 mm. The material testing apparatus 10 may be configured to have any necessary stroke length to appropriately test a given specimen or material.

[0114] The suspension system 300 is configured to support the armature 200 and control movement of the armature 200 relative to the stator assembly 400 in a manner such that there is no contact (such as sliding or rolling contact) between the armature 200 and the suspension system 300. By moving along the movement axis 500, the armature 200 may be configured to apply a force to the specimen, thereby inducing movement or mechanical stress (or both) along the movement axis 500.

[0115] The linear motor 100, armature 200, suspension system 300, and stator assembly 400 will be shown in more detail in subsequent figures. The mechanical attachment between the output shaft 210 and the specimen may be conventional. For example, the configuration of the specimen may depend on the specific material test to be performed. The specimen may be considered any material, component, fixture, device, etc.

[0116] The armature 200 may be a magnetic device having a magnetic array 212 located or otherwise disposed within a magnet frame 214. Although not shown, the magnetic array 212 extends through the magnet frame 214 to opposite sides of the armature 200. Although only one side of the armature 200 is shown, the armature 200 may be geometrically or substantially mirror-imaged about a first symmetry plane that extends parallel to both the movement axis 500 and a horizontal axis 510 perpendicular to the movement axis, as shown. The armature 200 may also be magnetically and geometrically or substantially mirror-imaged about a second symmetry plane that extends parallel to the movement axis 500 and a second horizontal axis 520 perpendicular to the movement axis and further perpendicular to the first movement axis.

[0117] The armature 200 is held in place by a suspension system 300, which includes a first side frame 310 and a second side frame 312. The first side frame 310 and the second side frame 312 are configured to support the armature 200. The suspension system 300 may be a structural body (e.g., the first side frame 310 and the second side frame 312) that includes at least one opening (e.g., a first side frame 310 and a second side frame 312) for receiving the armature 200 therein. Figure 6 and Figure 7 The first armature opening 395 and the second armature opening 397 are shown, and other embodiments are also contemplated. The coil stack within the stator assembly 400 is located between the first side frame 310 and the second side frame 312. The suspension system 300 also includes a top mounting plate 314 and a bottom mounting plate 316 for attaching, connecting or otherwise mounting the first side frame 310 and the second side frame 312 and the stator assembly 400.

[0118] In the illustrated embodiment, the linear motor 100 is a three-phase linear motor. Figure 2 Depicts a view taken at arrow AA according to one embodiment. Figure 1 1 is a cross-sectional view of a linear motor 100. The linear motor 100 includes a first coil subassembly 414 having a first coil stack 410 and a second coil subassembly 416 having a second coil stack 412 housed within the stator assembly 400, the first coil subassembly and the second coil subassembly being adjacent to two opposite sides of a magnet array 212 exposed on opposite sides of a magnet frame 214 of the armature 200. The coil stacks of the stator assembly 400 provide movement of the magnetic armature 200 when subjected to electrical power.

[0119] The first coil subassembly 414 includes a first laminated core 422 having six separate magnetic poles 418a, 418b, 418c, 418d, 418e, 418f, and six separate windings 420a, 420b, 420c, 420d, 420e, 420f are respectively wound around the six separate magnetic poles, thereby forming a first coil stack 410. Similarly, the second coil subassembly 416 includes a second laminated core 422 having six separate magnetic poles 424a, 424b, 424c, 424d, 424e, 424f, and six separate windings 426a, 426b, 426c, 426d, 426e, 426f are respectively wound around the six separate magnetic poles, thereby forming a second coil stack 412. As shown, the first phase A is connected to the top windings 420a, 426a and the fourth windings 420d, 426d from the top of each of the first coil stack 410 and the second coil stack 412. The second phase B is connected to the second windings from the top 420b, 426b of each of the first coil stack 410 and the second coil stack 412 and the fifth windings 420e, 426e from the top. The third phase C is connected to the third windings from the top 420c, 426c of each of the first coil stack 410 and the second coil stack 412 and the sixth windings 420f, 426f from the top.

[0120] As shown, each magnet in the magnet array 212 includes a polarity that is reverse or opposite to that of the adjacent magnet. In particular, the magnet array 212 includes fourteen rows, with two magnets in each row. Other embodiments may include more or fewer than fourteen rows, with two magnets in each row. For example, a shorter stroke version of the linear motor 100 may include thirteen, twelve, eleven, ten, or fewer pairs of magnets. A longer stroke version of the linear motor may include fifteen, sixteen, seventeen, eighteen, nineteen, twenty, or more pairs of magnets. This three-phase configuration generates magnetic fields that interact with the magnet array 212 of the armature 200, thereby causing the armature 200 to move up and down (i.e., back and forth) along the movement axis 500 by a certain distance. The magnet array 212 may be arranged to be close to each of the first coil stack 410 and the second coil stack 412 within a predetermined gap tolerance. The gap span may be maintained with a tight tolerance to prevent the magnet array 212 from being attracted to one or the other of the first coil stack 410 and the second coil stack 412 as much as possible during operation. Although it may not be possible to form a completely equal gap between each side of the magnet array 212 and the coil stacks 410, 412, the lateral stiffness of the suspension system 300 may be configured to support the generated lateral forces through slightly unequal gaps. The lateral stiffness of the suspension system 300 (including its air bushings (described in more detail below)) may be high enough to counteract any lateral forces caused by the unequal gaps.

[0121] Although the illustrated embodiment includes a three-phase linear motor having a three-phase stator assembly 400, the principles described herein in connection with the armature 200, the suspension system 300, and the stator assembly 400 may be incorporated into a single-phase linear motor or any other multi-phase linear motor. Although it has been found that three-phase systems are capable of achieving higher stroke lengths than single-phase systems, in applications where stroke length is not critical, a single-phase linear motor may be employed without departing from various embodiments of the present invention.

[0122] Figure 3 Depicted is a Figure 1 310 , wherein cooling ducts 318, 320, 322 are shown. The cooling ducts 318, 320, 322 may be features that are removably attached to each of the first side frame 310 and the second side frame 312 of the suspension system 300. As shown, the first cooling duct 318 is attached to the front side of the first side frame 310, and the second cooling duct 320 is attached to the rear side of the first side frame 310. Similarly, the third cooling duct 322 is shown as being attached to the front side of the second side frame 312. When hidden, the fourth cooling duct may be attached to the rear side of the second side frame 312. Each of the cooling ducts 318, 320, 322 may provide a passage through which air moves. Additional fans 324 , 326 , 328 are shown attached to each cooling duct 318 , 320 , 322 , respectively, to facilitate circulating, circulating, and / or blowing of air through the cooling ducts 318 , 320 , 322 .

[0123] Now see the attached Figure 4 and Figure 5 , Figure 4 Depicted is a Figure 1 and Figure 3 1 is a perspective view of a first side frame 310 of a linear motor 100 , revealing an upper side 330 . Figure 5 Depicted is a Figure 1 and Figure 3 332. The first side frame 310 and the second side frame 312 may be mirror images of the same size and features. In other embodiments, the first side frame 310 and the second side frame 312 may each include one or more unique features, dimensions, etc. (not shown).

[0124] The dimensions of the first side frame 310 and the second side frame 312 of the suspension system 300 can be set to support the flow of air from the ducts 318, 320, 322 and into the gaps between each of the windings 420a, 420b, 420c, 420d, 420e, 420f, 426a, 426b, 426c, 426d, 426e, 426f of the stator assembly 400 and / or across the magnets of the magnet array 212. To achieve this, the first side frame 310 and the second side frame 312 can each include an I-shaped cross-section. Thus, the first side frame 310 and the second side frame 312 each include an upper portion 340, 342, and each include an intermediate portion 344, 346, and each include a lower portion 348, 350. Referring back to Figure 3 , the cooling ducts 318, 320, 322 are attached between the top and bottom of the I-shaped cross-section such that the first side frame 310 and the second side frame 312 define an air passage from the cooling ducts 318, 320, 322 to the stator assembly 400 and / or the magnet array 212. In other embodiments, the shapes of the first side frame 310 and the second side frame 312 can be more robust than the embodiments shown and can include openings, slots, ports, etc. to facilitate air flow.

[0125] Still referring to Figure 4 and Figure 5 , the first side frame 310 includes a first opening 334 in which an air bushing 336a is disposed, and the second side frame 312 includes a second opening 338 in which another air bushing 336b is disposed. The first opening 334 and the second opening 338 are cylindrical openings having a circular cross-section that is configured to receive the cylindrical air bushings 336a, 336b (hereinafter generally referred to as air bushing 336). However, in other embodiments, other shapes of openings are also contemplated. For example, without departing from the scope of the various inventive concepts described herein, triangular or rectangular openings can be employed in the first side frame 310 and the second side frame 312 having opposing flat bearing arrays instead of using the cylindrical air bushing 336.

[0126] Each of the first side frame 310 and the second side frame 312 further includes a magnetic damping system configured to absorb kinetic energy from the movement of the armature 200 when the power to the linear motor 100 is cut off. Specifically, the magnetic damping system is shown as two magnet arrays 380a, 380b which are disposed on each of the first side frame 310 and the second side frame 312 parallel to the movement axis 500 of the armature 200. In addition to absorbing kinetic energy when power is cut off, the magnetic damping system can also be configured to reduce instability and make the linear motor 100 more stable. For example, during normal operation, the magnetic damping system can be tuned by adjusting the gap or using different numbers or types of magnets to provide an optimal amount of damping, thereby improving system control.

[0127] Although Figure 4 the first magnet array 380a disposed on the first side frame 310 is clearly shown, the second side frame 312 includes a second magnet array 380b (more clearly shown in Figure 6 ). Each magnet in each of the magnet arrays 380a, 380b is shown as a flat sheet permanent magnet. These magnet arrays 380a, 380b are separate from the magnet array 212 used by the armature 200 to generate the movement of the armature 200 through the linear motor 100. Each of the magnet arrays 380a, 380b can be positioned close to the conductive non-magnetic surface of the armature 200 which extends parallel to the movement axis 500 of the armature 200 when the linear motor 100 is assembled and operated. There is a small gap (e.g., less than 1 cm, less than 0.5 cm, or less than 0.25 cm) between each of the magnet arrays 380a, 380b and the conductive non-magnetic surface of the armature 200 close to it (more clearly shown in Figure 10 and described below). The first magnet array 380a and the second magnet array 380b can be configured to resist movement by using eddy currents induced by the movement of the conductive non-magnetic surface of the armature 200, thereby generating a damping effect on the moving armature during stop conditions. The number of magnets shown on each of the first magnet array 380a and the second magnet array 380b is twelve, but more or fewer magnets can be deployed. Each of the magnet arrays 380a, 380b includes a single row of magnets vertically disposed on the magnet holding surfaces 382a, 382b of each of the first side frame 310a and the second side frame 310b respectively. The magnet holding surfaces 382a, 382b can be vertically sized protrusions that extend from the surface of each of the first side frame 310a and the second side frame 310b close to the armature 200 when the linear motor 100 is assembled and operated.

[0128] The upper and lower surfaces of the first side frame 310 and the second side frame 312 may each include one or more alignment pins 352, 354. For example, the upper surface 330 of the first side frame 310 includes a first alignment pin 352 to facilitate attachment between the first side frame 310 and the upper plate 356. The lower surface 332 of the second side frame 312 is shown as including a second alignment pin 354 to facilitate attachment between the second side frame 312 and the lower plate 358. Although only the upper surface of the first side frame 310 is shown and the lower surface 332 of the second side frame 312 is shown, it should be understood that alignment pins may also be included on the lower surface of the first side frame 310 and the upper surface of the second side frame 312. The upper and lower surfaces of each of the first side frame 310 and the second side frame 312 may also include openings 360, which may be threaded, for example, for receiving attachment mechanisms (such as threaded screws, bolts, etc.) for attaching the first side frame 310 and the second side frame 312 to the upper plate 356 and the lower plate 358.

[0129] The first side frame 310 and the second side frame 312 each include two air supply openings 384, each air supply opening for each air bushing 336, each air bushing being configured to be disposed within the first opening 334 and the second opening 338, respectively. The air supply openings 384 may be configured to supply forced air from an air source (not shown) into the air bushings 336. The air supply openings 384 may be configured to directly receive air or, alternatively, may be configured to receive a pipe fitting, tube, or other device configured to transmit air therethrough. The first side frame 310 and the second side frame 312 also include three pressure relief openings 386 for each bushing, each bushing being configured to be disposed within the first opening 334 and the second opening 338. The air supply openings 384 and the pressure relief openings 386 are shown in Figure 7 and described in more detail below.

[0130] Figure 6 A perspective view of a frame sub-assembly 370 oriented to expose the upper side 362 is depicted according to one embodiment, the frame sub-assembly including a first side frame 310 connected between an upper plate 356 and a lower plate 358 and Figure 4 a second side frame 312. Figure 5 Figure 7 A perspective view of a frame sub-assembly 370 oriented to expose the lower side 364 is depicted according to one embodiment, the frame sub-assembly including a first side frame connected between an upper plate 356 and a lower plate 358 and Figure 4 a second side frame. Figure 5The second side frame. The upper plate 356 and the lower plate 358 are configured to attach the first side frame 310 and the second side frame 312 together and also provide attachment locations for attaching the first coil stack 410 and the second coil stack 412 of the stator assembly 300. Thus, the upper plate 356 and the lower plate 358 may include various openings, which may be threaded, for example, to receive attachment screws, bolts, or other mechanisms for assembling the frame subassembly 370 and also for attaching the frame subassembly 370 to other components (not shown) of the material testing system 10.

[0131] The upper plate 356 and the lower plate 358 may each include a plurality of x, y position openings 368a, 368b, 368c and circumferential (clocking) slots 366a, 366b, 366c to facilitate assembly. The x, y position openings 368a, 368b, 368c may be circular openings to receive circular pins and may prevent movement between the plates 356, 358 and the side frames 310, 312 through which the pins extend in their positions. The circumferential slots 366a, 366b, 366c may be elongated along the direction of movement to provide some movement between the plates 356, 358 and the side frames 310, 312 through which the pins extend in their positions.

[0132] For assembling the linear motor 100 and its frame subassembly 370, after placing the armature 200 within the frame subassembly 370, pins may be inserted into each of the x, y position openings 368b, 368c and the circumferential slots 336b, 336c of the lower plate 358. The pins may then be inserted into the x, y position opening 368a and the circumferential slot 366a of the upper plate 356. Once the pins have been placed through the circumferential slots 366a, 366b, 366c and the x, y position openings 368a, 368b, 368c, the method of assembling the linear motor 100 includes energizing the air bushings 336 within the first vertical opening 334 and the second vertical opening 338. In combination with the limited movement provided by the circumferential slots 366a, 366b, 366c, this air pressure may align the system, after which the upper plate 356 and the lower plate 356 may be fully tightened with bolts, screws, etc.

[0133] The upper plate 356 and the lower plate 358 may each include the same dimensions and features. For example, the upper plate 356 and the lower plate 358 may each include two armature shaft openings 394a, 394b, 394c, 394d that are configured to receive an armature shaft therein. When assembled, the first opening 334 of the first side frame 310 is aligned with the armature shaft openings 394a, 394c, and the second opening 338 of the second side frame 312 is aligned with the armature shaft openings 394b, 394d to provide left and right collective vertical openings that each extend through each of the upper plate 356, the corresponding first side frame 310 and second side frame 312, and the lower plate 358. The collective vertical openings each extend along an axis parallel to the movement axis 500.

[0134] The first armature opening 395 extends between the openings 394a, 394b of the upper plate 356, and the corresponding second armature opening 397 extends between the openings 394c, 394d of the lower plate 358. The armature openings 395, 397 may be configured to receive an armature therein and provide free movement of the armature therein. The upper bump stop 390a is shown extending from the upper plate 356, and the lower bump stop 390b extends from the lower plate 358. The bump stops 390a, 390b may provide a physical boundary for the movement of the armature 200. The bump stops 390a, 390b may be made of a soft elastomeric material such as FKM elastomer or the like to slow down deceleration.

[0135] The upper plate 356 is shown as including a first stack mounting surface 392a and a second stack mounting surface 392b. Similarly, the lower plate 358 is shown as including a third stack mounting surface 392c and a fourth stack mounting surface 392d. The stack mounting surfaces 392a, 392b provide surfaces on which the first coil stack 410 is mounted. Similarly, the stack mounting surfaces 392c, 392d provide surfaces on which the second coil stack 412 is mounted. Thus, the stack mounting surfaces 392a, 392b, 392c, 392d each include a plurality of openings that may be configured to have threads to receive screws, bolts, etc. The dimensions to which the stack mounting surfaces 392a, 392b, 392c, 392d extend into the upper plate 356 and the lower plate 358 may be precisely machined to provide a desired clearance distance between the moving armature 200 and the first coil stack 410 and the second coil stack 412.

[0136] Figure 8 A perspective cross-sectional view of the first side frame 310 according to one embodiment is shown, which shows two air bushings 336a, 336c disposed within the vertical opening 334 of the first side frame 310. Although in Figure 8Only the first side frame 310 is shown in section to expose the two air bushings 336a, 336c within the vertical opening 334, but the second side frame 312 may also include two air bushings 336 in the same manner. Thus, the subsequent description of the air bushings 336a, 336c applies to the two air bushings 336 located within the second side frame 312.

[0137] As shown, the first air bushing 336a of the first side frame 310 is positioned near the first upper end of the opening 334, while the second air bushing 336b is positioned near the second lower end of the opening 334. The air bushings 336a, 336b may each be mounted within the opening 334 in a compliant manner such that some movement between the air bushings 336a, 336b and the frame subassembly 370 is permitted. This compliant relationship may be provided by inserting the air bushings 336a, 336b into the opening 334 with an interference fit or a press fit. Additionally, the air bushings 336a, 336b are each shown as including a plurality of O-rings 372, which may be made of a compliant elastomeric material and provide some part of the compliance between the air bushings 336a, 336b and the opening 334 (and thus the frame subassembly 370). The air bushings 336a, 336b may each be installed by hand insertion into the opening 334 and may be removed by hand, for example, for maintenance.

[0138] The air bushings 336a, 336b each have a hollow cylindrical shape. The air bushings 336a, 336b each include an outer body 374 and an inner body 378 made of different materials. The inner body is a porous body that is air permeable, while the outer body 374 is air impermeable and has air receiving port openings 376. Thus, air is received into each of the air bushings 336a, 336b through the respective air receiving port openings 376. The air is then conveyed through the porous inner body 378. Since the outer body 374 is air impermeable and prevents the air received through the air receiving port openings 376 from escaping through the outer body 374, the received air is forced to escape only through the porous inner body 378, thereby creating an air pressure between the porous inner body 378 and the shaft of the armature received therein. The porous inner body 378 includes many (thousands, millions, etc.) sub-micron pores in the material that create air permeability. When the air bushings 336a, 336b receive air through the air receiving port openings 376, the air bushings 336a, 336b may be configured to provide a full 360-degree non-contact movement for the shaft of the armature received therein as the air escapes the body of the air bushings 336a, 336b through the inner body 378.

[0139] As shown in the cross-sectional view, the air supply opening 384 of the first side frame 310 extends through the body of the frame and is directly aligned with the corresponding receiving port opening 376. The pressure relief opening 386 also extends through the body of the frame and is aligned with the space between each of the four O-rings 372 on the bushing. The pressure relief opening 386 in the body of the first side frame 310 can facilitate the installation of the air bushings 336a, 336b and prevent any accumulation of air pressure between the outer body 374 of the air bushings 336a, 336b and the inner wall of the vertical opening 334 of the first side frame 310. Additional openings can be provided within the vertical opening 334 of the first side frame 310 to recycle the air introduced into the bushings 336a, 336b through the corresponding receiving port options 376 back into the system for the purpose of cooling at least one of the windings 420a, 420b, 420c, 420d, 420e, 420f, 426a, 426b, 426c, 426d, 426e, 426f or the magnet array 212 of the armature 200.

[0140] Although the test device 10 and the linear motor 100 are shown as including four air bushings in the air bushings 336 (two in each of the first side frame 310 and the second side frame 312), more or fewer air bushings can be included if needed to accommodate any collision forces caused by the magnetic attraction between the armature 200 and the coil stacks 410, 412. For example, some embodiments may only require two air bushings. Other embodiments may require six air bushings (three in each of the vertical openings 334, 338). In another contemplated embodiment, one or more additional air bushings can be configured to surround the specimen output shaft 210 extending from the armature 200 to provide additional suspension support for the system.

[0141] Figure 9 A perspective view of the armature 200 of a linear motor 100 according to one embodiment is depicted. Figure 1 and Figure 3 The armature 200 includes a magnet frame 214 in which the magnet array 212 extends between a top plate 220 and a bottom plate 222 in the direction of the movement axis 500. The top plate 220 and the bottom plate 222 are configured to connect, attach or otherwise assemble the magnet frame 214 and the magnet array 212 to the first side air bushing shaft 230 and the second side air bushing shaft 232. The first side air bushing shaft 230 and the second side air bushing shaft 232 also extend along the movement axis 500. The first side air bushing shaft 230 and the second side air bushing shaft 232 are shown as cylindrical shafts. The first side air bushing shaft 230 and the second side air bushing shaft 232 have tight dimensional tolerances for the internal dimensions of the air bushings 336 within the first opening and the second opening.

[0142] The air bushing 336 is configured to provide frictionless movement between the armature 200 and the frame sub - assembly 370 of the suspension system 300. The air bushing 336 operates without sliding or rolling friction between the inner surface of the air bushing 336 and the air bushing shafts 230, 232 of the armature 200. When air is forced through the inner body 378 of the air bushing 336, the air bushing shafts 230, 232 of the armature 200 are forced by the air to an intermediate point in the middle of the inner surface of the inner body 378. In one embodiment, the air bushing shafts 230, 232 may include a radius that is 3 to 5 micrometers smaller than the inner radius of the inner surface of the air bushing 336, so as to provide a space between the air bushing shafts 230, 232 and the inner surface of the inner body 378 of the air bushing 336 when the air bushing 336 is receiving an air flow and the system is operating. In one embodiment, the air bushing shafts 230, 232 include a radius that is 4 micrometers smaller (a diameter that is 8 micrometers smaller) compared to the inner surface of the air bushing 336. Other dimensions are envisioned to provide a frictionless and / or non - contact movement system between the air bushing shafts 230, 232 and the air bushing 336.

[0143] The top plate 220 and the bottom plate 222 are shown as having a width greater than the width of the magnet frame 214. This greater width provides a surface for engaging the bump stoppers 390a, 390b. In addition, the top plate 220 and the bottom plate 222 include connection openings 234 for receiving bolts, screws, or other attachment mechanisms for connection to the magnet frame 214. Various other connection openings may be provided for receiving other bolts, screws, etc., thereby also attaching the top plate 220 and the bottom plate 222 to the air bushing shafts 230, 232. The top plate 220 and the bottom plate 222 are shown as connecting the first air bushing shaft 230 and the second air bushing shaft 232 to the magnet frame 214 such that a first space extends between the first air bushing shaft 230 and the magnet frame 214 parallel to the movement axis 500, and similarly such that a second space extends between the second air bushing shaft 232 and the magnet frame 214 parallel to the movement axis. These spaces may be greater than the thickness of the body of the air bushing 336 and the first side frame 310 and the second side frame 312 surrounding its vertical openings 334, 338. Thus, these vertical spaces between the air bushing shafts 230, 323 and the magnet frame 214 enable the armature 200 to remain connected to the suspension system 300 while still allowing vertical movement of the armature 200 relative to the suspension system 300.

[0144] Figure 10 Depicted is, according to one embodiment, before assembly with the first air bushing shaft 230 and the second air bushing shaft 232, and the top plate 220 and the bottom plate 222 Figure 9The magnet frame 214 of the armature 200. The magnet frame 214 includes a body extending between an L-shaped left side 236 and an L-shaped right side 238. The L-shaped left side 236 and the L-shaped right side 238 extend along the vertical length of the magnet frame 214. The magnet frame 214 includes an opening located in the middle, which is configured to receive the magnet array 212. Each magnet of the magnet array 212 can be attached to the magnet frame 214 by epoxy resin around the edge of the magnet array 212 and around the edge of each individual magnet to fix the magnets to each other. The epoxy resin can be a temperature-resistant epoxy resin that does not degrade at the elevated temperatures to which the magnets can rise during operation. In other embodiments, the magnets can be attached to the magnet frame 214 by mechanical means such as by slots in a sheet integrated with protrusions or slots of the magnet frame 214. Another alternative or additional method can include using set screws to tighten, compress, or otherwise clamp down on the magnets along the edges of the magnets through the magnet frame 214.

[0145] Also shown in this figure is a magnet array 380a attached to one of the side frames 310, 312, where the side frame has been removed to enable viewing of the close dimensional relationship between the magnet array 380a and the magnet frame 214. The gap between the array magnet 380a and the magnet frame 214 can be optimized to provide a desired damping force when the system is turned off. For example, gaps of 0.3 mm, 0.25 mm, 0.2 mm, 0.15 mm are envisioned. Any gap that achieves the desired damping amount by interacting with eddy currents is envisioned.

[0146] Figure 11 Depicted according to one embodiment Figure 10 A portion of the magnet array 212 of the magnet frame. Views of several individual magnets 212a, 212b, 212c, 212d, 212e, 212f, 212g are shown, which have been enlarged to show the skew and dimensions of each magnet in the magnet array 212. The magnets 212a, 212b, 212c, 212d, 212e, 212f, 212g in the magnet array 212 ( Figure 11Each of those magnets shown and those magnets extending below the shown view can be a permanent magnet, such as an NdFeB magnet. Each of the magnets 212a, 212b, 212c, 212d, 212e, 212f, 212g of the magnet array 212 is shown as being skewed by a small angle, such as one degree. Thus, the magnets 212a, 212b, 212c, 212d, 212e, 212f, 212g can include a parallelogram shape such that the bottom edge and the top edge of each flat sheet magnet are not orthogonal to the side edges of the flat sheet magnet. As shown, the upper left edge of each of the magnets 212a, 212c, 212e is at a higher position compared to the upper right edge. Similarly, the upper right edge of each of the magnets 212b, 212d, 212f, 212g is higher than the upper left edge. In other words, when the magnet approaches the middle of the magnet array 212, the magnet size is lower compared to at the edge of the magnet array 212. This skew can also be reversed such that when the magnet approaches the middle of the magnet array 212, the magnet size is higher compared to at the edge of the magnet array 212. The skew can be any suitable amount of one degree, two degrees, three degrees, and can be optimized to reduce the cogging force during interaction with the magnetic field generated by the stator assembly 400.

[0147] In an exemplary embodiment, the width of each magnet can be between 50 mm and 100 mm, while the height can be between 10 mm and 50 mm. The thickness of each magnet can be between 10 mm and 22 mm. In one exemplary embodiment, the magnet can include a width of 70 mm, a height of 28 mm, and a thickness of 18 mm. These dimensions can be changed according to the force output required by the magnet array 212.

[0148] Figure 12 Depicted in accordance with one embodiment Figure 1 and Figure 3Perspective view of the first coil subassembly 414 of the linear motor 100. Although not shown, the second coil subassembly 418 may share the same feature structure and dimensions with the first coil subassembly 414. The coil subassembly 414 is shown as including a first laminated core 422 having six separate magnetic poles 418a, 418b, 418c, 418d, 418e, 418f (generally referred to as 418), and six separate windings 420a, 420b, 420c, 420d, 420e, 420f (generally referred to as 420) are respectively wound around the six separate magnetic poles, thereby forming a first coil stack 410. The laminated core 422 may include a number of laminations held together by stack pressing bars on each side. The laminated core 422 may include 200 laminations (metal sheets) made of, for example, M19 electrical steel. The laminations may include fins 428, which may increase the surface area of the laminated core 422 to facilitate cooling. In an exemplary embodiment, the pole pitch between the six separate magnetic poles 418a, 418b, 418c, 418d, 418e, 418f may be between 20 mm and 60 mm. In one embodiment, the pole pitch may be 38 mm. In some embodiments, the pole pitch between each of the magnetic poles 418a, 418b, 418c, 418d, 418e, 418f may be equal. In other embodiments, different pole pitches may be beneficial for optimizing heat distribution, magnetic field output, etc. In an exemplary embodiment, the thickness of the magnetic poles 418a, 418b, 418c, 418d, 418e, 418f may be between 10 mm and 20 mm. In one embodiment, the pole thickness may be 15.8 mm. The six separate windings 420a, 420b, 420c, 420d, 420e, 420f may be made of, for example, 16 AWG round wire and may include 168 turns. The windings 420a, 420b, 420c, 420d, 420e, 420f may each include six layers, each layer having 28 turns. Coil forms 440a, 440b, 440c, 440d, 440e, 440f (generally referred to as coil form 440) may also be included on each of the magnetic poles 418a, 418b, 418c, 418d, 418e, 418f. The coil forms 440a, 440b, 440c, 440d, 440e, 440f are described below and shown in Figure 14 as shown in.

[0149] Figure 13 Depicts according to one embodiment Figure 12Side view of the coil subassembly 414. After being wound around the magnetic poles 418a, 418b, 418c, 418d, 418e, 418f, there may be a gap 430 between the windings 420a, 420b, 420c, 420d, 420e, 420f. The gap 430 may allow a cooling air flow to move therethrough. The thickness of the gap 430 may each be a number of millimeters. For example, it is contemplated that the gap thickness between each of the windings 420a, 420b, 420c, 420d, 420e, 420f is 4.5. The gap thickness may, for example, be between 3 mm and 10 mm. In other embodiments, the gap thickness may be filled with a potting material, as described below and Figure 15 as shown.

[0150] Figure 14 Perspective view of one of the coil forms 440 having integrated cooling fins 448a, 448b, 448c, 448d, 448e, 448f according to one embodiment. The coil form 440 includes a body 442 extending from a base 444. The body 442 includes a generally rectangular cross-section that surrounds and forms an opening 446 sized to fit around and receive one of the magnetic poles 418. The coil form 440 also includes a plurality of fins 448a, 448b, 448c, 448d, 448e, 448f extending from the body 442. Winding gaps 450a, 450b may be located between the plurality of fins 448a, 448b, 448c, 448d, 448e, 448f. The winding gaps may allow the wires of the winding 420 to be wound between each of the sections of the coil form 440. The fins 448a, 448b, 448c, 448d, 448e, 448f of the coil form 440 may be tall enough to extend through the winding 420 and out into the forced convection zone between the coils. The coil form 440 may thus help increase the conduction of heat away from the winding 420. The fins 448a, 448b, 448c, 448d, 448e, 448f may also increase the available surface area for forced convection.

[0151] Figure 15 Depicts, according to one embodiment, having heat pipes 475 and additional cooling fins 470 attached to these heat pipes Figure 12Perspective view of the coil subassembly 414. This embodiment can be applied as a supplement or alternative to the coil bobbin 440. In this embodiment, potting materials 460a, 460b, 460c, 460d, 460e can be included in each of the gaps between windings 420a, 420b, 420c, 420d, 420e, 420f. Four heat dissipation tubes 475 extending from the potting materials within each of the gaps are shown. For example, four heat dissipation tubes 475a extend from the left between the top gaps in the windings, four heat dissipation tubes 475b extend from the left between the second gaps, four heat dissipation tubes 475c extend from the left between the third gaps, four heat dissipation tubes 475d extend from the left between the fourth gaps, and four heat dissipation tubes 475e extend from the left between the fifth gaps. Similarly, four heat dissipation tubes 475f extend from the right between the top gaps in the windings, four heat dissipation tubes 475g extend from the right between the second gaps, four heat dissipation tubes 475h extend from the right between the third gaps, four heat dissipation tubes 475i extend from the right between the fourth gaps, and four heat dissipation tubes 475j extend from the right between the fifth gaps. In some embodiments, the heat dissipation tubes 475a and 475f extending from the left and right respectively can be the same component (i.e., a single heat dissipation tube extending in two directions). The heat dissipation tubes can be configured to transfer heat from the windings 420 to a plurality of cooling fins 470a, 470b located on each side. As shown, each of the left and right sides includes eight cooling fins 470. The cooling fins 470 can provide an increased surface area for cooling. In this embodiment, as an alternative or supplement to forcing air through the gaps between the windings 420, the cooling air is configured to blow over the cooling fins 470 and the fins 428 of the laminated core 422.

[0152] Figure 16 Depicts a Figure 1 and Figure 3 electrical schematic diagram of a three - phase motor of a linear motor 100 according to one embodiment, where e1, e2, e3 are voltages driven by an amplifier to control three corresponding currents i1, i2, i3, and thus control the force output of the motor. Inductors L 11 , L 22 , L 33 exist in series with the resistance R of each phase.

[0153] Using a three - phase motor of the linear motor 100, the acceleration of the armature can be defined as:

[0154] mx″(t) = -kx(t) - bx′(t)+NBL1i1(t)+NBL2i2(t)+NBL3i3(t)-mg

[0155] Where m is the mass of the armature, x”(t) is the acceleration of the armature, k is the spring constant of the system (which will be related to the spring constant of the test material to which the armature is connected, or if the armature is not connected to the test material, the spring constant is zero), b is the damping constant, x(t) is the position of the armature, x’(t) is the velocity of the armature, is an array of motor force / counter-EMF constants, each phase being separated from each other by 120°, and i is the current in each of phases a, b, and c.

[0156] The voltage in the first branch can be defined as:

[0157] e1(t) = L 11 i′1(t) + L 12 i′2(t) + L 13 i′3(t) + R1i1(t) + x′(t)NBL1

[0158] Where e1[t] is the voltage of the first phase, L 11 is the inductance in the first phase induced by the inductor of the first phase, L 12 is the inductance in the first phase induced by the inductor of the second phase, L 13 is the inductance in the first phase induced by the inductor of the third phase, i1’(t), i2(t), and i3(t) are the changes in the currents in phases a, b, c, and R is the resistance of each individual phase. Similarly, the voltages of the second and third branches can be defined as:

[0159] e 2(t) = L 21 i′1(t) + L 22 i′2(t) + L 23 i′3(t) + R2 i2(t) + x′(t)NBL2

[0160] e 3(t) = L 31 i′1(t) + L 32 i′2(t) + L 33 i′3(t) + R3 i3(t) + x′(t)NBL3

[0161] As long as there is movement in the armature, even when the voltages in the three branches (e1(t), e2(t), e3(t)) are cut off to zero, the x’(t)NBL term in each voltage equation will not be zero because the armature is moving. This indicates that the EMF is generated by these x’(t)NBL terms, which generates a change in current and thus a force that will resist this movement according to the acceleration formula. Therefore, the movement of the three-phase motor and the armature is configured to generate a damping force when the current in each phase is cut off or short-circuited, which slows down the movement of the armature in addition to the eddy current magnet system described above.

[0162] Accordingly, embodiments of the present invention may include a suspension system that supports the range of motion of an armature without physically contacting the armature and without sliding and / or rolling friction between the suspension system and the armature. For example, the suspension system may be configured to facilitate movement of the armature relative to the stator assembly in one dimension without physically contacting the armature. In one embodiment or implementation, an air bushing may provide, support, or otherwise facilitate the range of motion (stroke length) of the armature in one dimension (e.g., back and forth along a single axis of movement) without mechanically or structurally connecting, attaching, or contacting the armature during operation of the suspension system. The suspension system may be configured to limit movement of the armature in that one dimension or along that one axis of movement, or at least substantially limit that movement (in the case where the air bushing is compliant and allows very little compliance in another dimension).

[0163] In an exemplary embodiment, the absence of mechanical or structural connection prevents contact friction between the suspension system and the armature during operation or movement and may be provided by an air gap between the air bushing of the suspension system and the air bushing shaft of the armature. Thus, the suspension system envisioned herein produces a support system for maintaining precise movement of the armature without structural contact or connection in a single dimension or along a single axis of movement. Thus, the suspension system envisioned herein may be considered to be in indirect mechanical communication with the armature during its operation and movement (e.g., via an air gap).

[0164] Methods of operating a linear motor and / or a material testing device or system are also envisioned. For example, the methods envisioned include providing a linear motor having a polyphase stator assembly, an armature proximate the polyphase stator assembly, and a suspension system. The method includes: receiving power by the polyphase stator assembly; moving the armature back and forth along an axis of movement after receiving power by the polyphase stator assembly; and supporting the armature with the suspension system by controlling movement of the armature relative to the polyphase stator assembly such that no sliding or rolling contact occurs between the armature and the suspension system. The method includes: using a three-phase linear motor and stator assembly to generate a magnetic field that moves the magnetic armature. The method may include: moving the armature back and forth along the axis of movement with a stroke length greater than 70 mm, 80 mm, 90 mm, or 100 mm. The methods envisioned include: arranging magnetic poles in the stator such that the phases alternate in an A-B-C-A-B-C relationship.

[0165] In addition, the contemplated method includes providing a stator assembly, an armature having an array of flat magnets disposed thereon proximate to the stator assembly, and a suspension system. The contemplated method includes: receiving power by the stator assembly; exposing the array of flat magnets to a magnetic field generated by the stator assembly; generating a back-and-forth movement in the armature by the array of flat magnets; and supporting the armature with the suspension system by controlling the movement of the armature relative to the multiphase stator assembly such that no sliding or rolling contact occurs between the armature and the suspension system. The method may further include: skewing the flat magnets within the array of flat magnets at a skew angle between 0.5 degrees and 5 degrees.

[0166] Further still, the contemplated method includes providing a stator assembly, an armature proximate to the stator assembly, and a suspension system. The method includes: receiving power by the stator assembly; causing the armature to move back and forth along a movement axis after receiving power by the stator assembly; supporting the armature with the suspension system without physically contacting the armature through the suspension system during movement. The method includes: allowing the armature to move relative to the suspension system through the suspension system without sliding or rolling contact between the armature and the suspension system and without a structural connection between the armature and the stator assembly. The method may further include: providing at least one air bushing in the suspension system. The method may include: allowing the armature to move relative to the suspension system through the air bushing without sliding or rolling contact between the armature and the suspension system. The method employing an air bushing may include: using recirculated air from the air bushing to cool components of the linear motor, such as the stator assembly or its magnets.

[0167] The contemplated method further includes providing a stator assembly, an armature proximate to the stator assembly, a suspension system, and a magnetic damping system. The method includes: receiving power by the stator assembly; causing the armature to move back and forth along a movement axis after receiving power by the stator assembly; supporting the armature with the suspension system by controlling the movement of the armature relative to the multiphase stator assembly such that no sliding or rolling contact occurs between the armature and the suspension system; cutting off power to the stator assembly; and absorbing the kinetic energy of the armature movement by the magnetic damping system when power to the linear motor is cut off. In cases where the damping method employs a multiphase linear motor such as a three-phase linear motor, the method may include: simultaneously cutting off power to each phase in the phases and using the generated eddy currents to damp the movement of the armature. The method further includes: using the movement of the armature between the coils of the system to generate a current that resists the movement of the armature and thus generates a force that resists the movement of the armature.

[0168] While embodiments of the present invention have been described herein for purposes of illustration, many modifications and changes will become apparent to those skilled in the art. Accordingly, the appended claims are intended to cover all such modifications and changes that fall within the true spirit and scope of the present invention.

[0169] The description of the various embodiments of the present invention is for illustrative purposes and is not intended to be exhaustive or limited to the disclosed embodiments. For example, although lacking any mechanical connection, the attachment between the suspension system 300 and the armature 200 in the embodiments described herein is a key inventive concept of some of the embodiments of the present invention described herein and other inventive embodiments, and other aspects of the inventive concepts described herein can be incorporated into a suspension system with connections or attachments as taught in U.S. Patent No. 6,405,599. For example, embodiments of the present invention can utilize a multiphase or three-phase linear motor, a flat magnet array armature, and / or a damping system as described herein, where the attached flexure member suspension system is described in U.S. Patent No. 6,405,599. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein are chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable other ordinary skilled artisans in the art to understand the embodiments disclosed herein.

Claims

1. A testing device, comprising: A linear motor, the linear motor including a stator assembly, wherein the stator assembly includes a first coil sub-assembly and a second coil sub-assembly; An armature, the armature being mechanically coupled to a specimen and configured to move relative to the stator assembly by operation of the linear motor, wherein the armature is located between and extends between the first coil sub-assembly and the second coil sub-assembly; And A suspension system configured to facilitate movement of the armature relative to the stator assembly along a movement axis without physically contacting the armature during movement, Wherein the suspension system includes at least one air bushing configured to allow movement of the armature relative to the suspension system without sliding or rolling contact between the armature and the suspension system, Wherein the at least one air bushing includes an outer body and an inner body made of different materials, and the inner body is an air-permeable porous body, while the outer body is air-impermeable and receives air through a corresponding air connection port opening of the suspension system.

2. The testing device according to claim 1, wherein the suspension system includes a frame body having a first opening extending along a first axis parallel to the movement axis, wherein the at least one air bushing is located within the first opening, and wherein the armature includes a first air bushing shaft extending within the first opening.

3. The testing device according to claim 2, wherein the at least one air bushing includes a first air bushing and a second air bushing, the first air bushing being positioned near a first end of the first opening, and the second air bushing being positioned near a second end of the first opening.

4. The testing device according to claim 3, wherein the frame body includes a second opening extending along a second axis parallel to the movement axis, and wherein the armature includes a second air bushing shaft extending within the second opening, wherein the second opening includes a third air bushing and a fourth air bushing, the third air bushing being positioned near a first end of the second opening, and the fourth air bushing being positioned near a second end of the second opening.

5. The testing device according to claim 2, wherein the at least one air bushing is mounted in the first opening of the frame body in a compliant manner such that some movement between the air bushing and the frame body is allowed.

6. The testing device according to claim 2, wherein the at least one air bushing is removably attached in the first opening of the frame body by an interference fit.

7. The testing device according to claim 6, wherein the at least one air bushing has a hollow cylindrical shape, and wherein the first air bushing shaft is a cylindrical shaft having a radius that is 3 to 5 micrometers smaller than the inner radius of the at least one air bushing.

8. The testing device according to claim 4, wherein the armature includes a magnet frame having a plurality of permanent magnets disposed thereon, wherein the first air bushing shaft extends parallel to the magnet frame, and wherein a top end plate and a bottom end plate connect the first air bushing shaft and the second air bushing shaft to the magnet frame such that a first space extends parallel to the movement axis between the first air bushing shaft and the magnet frame, and such that a second space extends parallel to the movement axis between the second air bushing shaft and the magnet frame, the testing device further including a duct system configured to use an air flow passing through the at least one air bushing to cool at least one of the coils of the first coil subassembly and the second coil subassembly and the armature.

9. The testing device according to claim 8, wherein the armature includes a specimen shaft extending from at least one of the top end plate and the bottom end plate, and wherein a fifth air bushing surrounds the specimen shaft.

10. A linear motor, comprising: a stator assembly configured to receive power, wherein the stator assembly includes a first coil subassembly and a second coil subassembly; an armature disposed adjacent to the stator assembly and configured to move relative to the stator assembly when the stator assembly receives power, wherein the armature is located between and extends between the first coil subassembly and the second coil subassembly; and a suspension system configured to facilitate movement of the armature relative to the stator assembly along a movement axis without physically contacting the armature during movement, wherein the suspension system includes at least one air bushing configured to allow the armature to move relative to the suspension system without sliding or rolling contact between the armature and the suspension system, wherein the at least one air bushing includes an outer body and an inner body made of different materials, and the inner body is an air-permeable porous body, while the outer body is air-impermeable and receives air through corresponding air connection ports of the suspension system.

11. The linear motor according to claim 10, and wherein the suspension system includes a frame body having a first opening extending along a first axis parallel to the movement axis, wherein the at least one air bushing is located within the first opening, and wherein the armature includes a first air bushing shaft extending within the first opening.

12. The linear motor according to claim 11, wherein the at least one air bushing includes a first air bushing and a second air bushing, the first air bushing being positioned adjacent a first end of the first opening, and the second air bushing being positioned adjacent a second end of the first opening.

13. The linear motor according to claim 12, wherein the frame body includes a second opening extending along a second axis parallel to the moving axis, and wherein the armature includes a second air bushing shaft extending within the second opening, wherein the second opening includes a third air bushing and a fourth air bushing, the third air bushing being positioned near a first end of the second opening, and the fourth air bushing being positioned near a second end of the second opening.

14. The linear motor according to claim 11, wherein the at least one air bushing is mounted in the first opening of the frame body in a compliant manner such that some movement between the air bushing and the frame body is allowed.

15. The linear motor according to claim 11, wherein the at least one air bushing is removably attached in the first opening of the frame body by an interference fit.

16. The linear motor according to claim 15, wherein the at least one air bushing has a hollow cylindrical shape, and wherein the first air bushing shaft is a cylindrical shaft having a radius that is 3 to 5 micrometers smaller than the inner radius of the at least one air bushing.

17. The linear motor according to claim 13, wherein the armature includes a magnet frame having a plurality of permanent magnets disposed thereon, wherein the first air bushing shaft extends parallel to the magnet frame, and wherein a top end plate and a bottom end plate connect the first air bushing shaft and the second air bushing shaft to the magnet frame such that a first space extends parallel to the moving axis between the first air bushing shaft and the magnet frame, and such that a second space extends parallel to the moving axis between the second air bushing shaft and the magnet frame, the linear motor further including a duct system configured to use an air flow passing through the at least one air bushing to cool at least one of the coils of the first coil subassembly and the second coil subassembly and the armature.

18. A method for operating a linear motor, comprising: providing a stator assembly, an armature adjacent to the stator assembly, and a suspension system, wherein the suspension system includes at least one air bushing configured to allow the armature to move relative to the suspension system without sliding or rolling contact between the armature and the suspension system, wherein the stator assembly includes a first coil subassembly and a second coil subassembly, wherein the armature is located between and extends between the first coil subassembly and the second coil subassembly, wherein the at least one air bushing includes an outer body and an inner body made of different materials, and the inner body is an air-permeable porous body, while the outer body is air-impermeable and receives air through a corresponding air connection port opening of the suspension system; receiving power by the stator assembly; After receiving power from the stator assembly, move the armature back and forth relative to the stator assembly along a movement axis; Support the armature with the suspension system without physically contacting the armature during the movement.

Images