WO2002065615A2 - Linear stepper motor, magnetizing fixture, and methods - Google Patents
Linear stepper motor, magnetizing fixture, and methods Download PDFInfo
- Publication number
- WO2002065615A2 WO2002065615A2 PCT/US2002/005028 US0205028W WO02065615A2 WO 2002065615 A2 WO2002065615 A2 WO 2002065615A2 US 0205028 W US0205028 W US 0205028W WO 02065615 A2 WO02065615 A2 WO 02065615A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- stepper motor
- linear stepper
- cylindrical
- shaft
- conductive wire
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K41/00—Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path
- H02K41/02—Linear motors; Sectional motors
- H02K41/03—Synchronous motors; Motors moving step by step; Reluctance motors
- H02K41/031—Synchronous motors; Motors moving step by step; Reluctance motors of the permanent magnet type
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
- H02K15/02—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies
- H02K15/03—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies having permanent magnets
Definitions
- the present invention relates to stepper motors generally and, more particularly, but not by way of limitation, to a novel linear stepper motor, a fixture for the magnetization of the shaft thereof, and methods of use and manufacture.
- Some linear stepper motors convert rotary motion to linear motion by mechanical means such as through the use of a threaded nut and lead screw.
- Conventional linear motors that directly transfer electromagnetic energy in the stator poles to linear movement of a shaft typically employ toothed structures or have relatively complicated slide/stator arrangements. In either case, the manufacture of such motors is relatively expensive and the motors typically have high parts counts.
- One technique is to glue together cylindrical segments of N and S magnets. That technique, however, is time consuming and results in a somewhat weak structure.
- Another technique is to roll a cylinder of ferromagnetic material over a flat plate orthogonal to a series of alternating N and S magnetic strips. This technique is somewhat clumsy and suffers from the fact that the resulting magnetized shaft is of fairly weak magnetic strength.
- a linear stepper motor comprising; a stator structure; an axially extending, cylindrical, permanent magnet shaft magnetically interacting with said stator structure; and said axially extending, cylindrical, permanent magnet shaft having a smooth surface along a portion thereof with axially alternating radial N and S poles defined in said smooth surface.
- the present invention also provides a method of magnetizing the shaft of such a motor and a fixture and method of manufacturing the fixture therefor.
- a shaft for a linear stepper motor that can permit rotational motion.
- an "inside-out" motor is provided in which the linearly moving member is external to the stator structure.
- Figure 1 is a fragmentary, side elevational view, partially in cross- section, of a linear stepper motor constructed according to a first embodiment of the present invention.
- Figure 2 is a rear elevational view of the motor of Figure 1.
- Figure 3 is an isometric view of a grooved mandrel for use in fabricating a fixture for magnetizing the shaft of the motor of Figure 1.
- Figure 4 is an isometric view of the mandrel of Figure 3 with a conductive wire inserted in the grooves of the mandrel.
- Figure 5 is an fragmentary, schematic, isometric view of the conductive wire showing the path of a direct current flowing therein.
- Figure 6 is an isometric view, partially cut-away, showing the mandrel of Figure 3 inserted in a potting fixture.
- Figure 7 is an isometric view showing a magnetizing fixture for magnetizing the shaft of the motor of Figure 1.
- Figure 8 is an isometric view showing a shaft according to a second embodiment of the present invention.
- Figure 9 is a top plan view of a linear motor constructed according to a third embodiment of the present invention.
- Figure 10 is a cutaway side elevational view of the motor of Figure 9.
- Figure 11 is a side elevational view of the moving member of the motor of Figure 9.
- Figure 12 is a side elevational view of a mandrel for magnetizing the cylindrical moving member of the motor of Figure 9.
- Figure 13 is an end elevational view of the mandrel of Figure 12.
- Figure 14 is a fragmentary, schematic, isometric view of a conductive wire for use with the mandrel of Figure 12.
- Figure 15 is an end elevational view of the conductive wire of Figure 14.
- Figure 1 illustrates a linear stepper motor, constructed according to a first embodiment of the present invention, and generally indicated by the reference numeral 20.
- Motor 20 includes a shaft, or slider, 30 having a smooth outer peripheral surface (at least the portion thereof illustrated) and inserted in a stator structure, generally indicated by the reference numeral 32, for axial back and forth motion of the shaft with respect to the stator structure.
- Shaft 30 includes a plurality of alternating N and S nonsalient poles, as at 34 and 36, respectively, formed around the periphery thereof, which poles may be formed as described below.
- Shaft 30 is preferably a hollow cylinder of ceramic or rare earth magnetic material, although the shaft may be solid or may have a core of ferromagnetic or other material with a hollow cylinder of the magnetic material disposed around the core.
- Shaft 30 can be economically constructed, for example, by conventional extrusion techniques that can produce a shaft of any given length or the shaft can be cut to a suitable length from extruded stock. At least the portion of shaft 30 containing the N and S poles is non-segmented and is constructed of a single piece of material.
- Stator structure 32 includes first and second, cylindrical, coils 40 and 42, respectively, encircling shaft 30, and conventionally wound on first and second annular bobbins 44 and 46.
- Bobbins 44 and 46 are formed of an electrically insulating material such as Delrin®.
- First and second bobbins 44 and 46 are spaced apart by a first spacer 50 and the second bobbin may be spaced apart from an end plate 52 of motor 20 by a second spacer 54.
- First and second spacers 50 and 54 may also provide bearing surfaces for shaft 30, in which case the first and second spacers are preferably of a material having a high degree of lubricity such as Delrin®.
- First bobbin 44 spaces apart annular pole plates 60 and 62, while second bobbin 46 spaces apart annular pole plates 64 and 66.
- a steel band 68 surrounds and is in good electrical contact with annular pole plates 60, 62, 64, and 66, thus completing the circular electromagnetic circuit.
- Annular pole plates 60, 62, 64, and 66 have nonsalient poles.
- shaft 30 may be made to incrementally "step" to the left or right on figure 1. It will be further understood that one or both ends of shaft 30 may be attached to, or bear against, one or more elements of another device (not shown).
- motor 20 is shown as having one set of two-phase stator sections, that is, the motor has two coils, it will be understood that other arrangements are possible as well.
- two or more sets of two-phase stator sections may be provided for greater power, the additional sets of stator sections being added serially in a modular manner.
- Figure 2 illustrates some of the elements of motor 20 ( Figure 1) and illustrates conductors 70 that are used to energize stator structure 32 and mounting holes 72 defined in end plate 52.
- motor 20 as shown ( Figure 1) in its minimum configuration is constructed of only 11 individual elements that may be held together principally with a suitable adhesive or other conventional means may be provided to secure together the elements of motor 20.
- Figure 3 illustrates a mandrel 100 that can be used in constructing a fixture for use in magnetizing shaft 30 ( Figure 1).
- a cylindrical mandrel 100 has a plurality of parallel, cylindrical grooves, as at 110, cut in the outer periphery thereof, the groove having a width approximating the diameter of a wire conductor to be used in magnetizing shaft 30.
- Mandrel 100 is constructed of a non-magnetic, non-electrically-conducting material, with the spacing of grooves 110 being determined by the final magnetic widths of poles 34 and 36 on shaft 30.
- Figure 4 illustrates a conductive wire 150 serially disposed in grooves 110 in mandrel 100.
- Figure 5 illustrates the current path in conductive wire 150, each nearly complete circle shown on Figure 5 representing a turn of conductive wire 150 in one of grooves 110. It will be noticed that the current flow represented by the arrows in conductive wire 150 in adjacent turns of the conductive wire are in opposite directions.
- Figure 6 illustrates mandrel 100, with conductive wire 150 placed in grooves 110, disposed in a cylindrical, hollow potting fixture 200.
- a suitable potting compound such as an epoxy material, is poured into an annulus 210 defined between the outer surface of mandrel 100 and the inner surface of potting fixture 200. After hardening, the potting compound holds conductive wire 150 in place in grooves 110.
- Figure 7 illustrates a finished magnetizing fixture, generally indicated by the reference numeral 300.
- Fixture 300 comprises mandrel 100 with an outer coating of potting compound 310 and ends of conductive wire 150 extending therefrom .
- a central axial bore 320 has been created, or enlarged, through mandrel 100 to bring conductive wire 150 near to the inner surface of the mandrel or even to be partially exposed, as shown on Figure 7, if desired.
- Shaft 30 of motor 20 ( Figure 1) can now be inserted into fixture 300 and a high level of direct current passed through conductive wire 150 to magnetize alternating N and S poles 34 and 36 along a selected length thereof.
- Such an arrangement provides an economical and rapid method of magnetizing shaft 30 and nearly any strength of magnetization can be provided, depending on the magnet material, since only one quick burst of direct current is necessary and that can be in a wide range of voltages.
- Motor 20 ( Figure 1) has a number of important features.
- motor 20 is of a brushless, magnetically coupled, bi-directional, non-arcing design, having long operational life, with permanently magnetized output shaft 30.
- Motor 20 runs on conventional stepper motor drives and can be microstepped for increased resolution and accuracy.
- Shaft 30 is the only moving part and it can be rotated 360° continuously or intermittently in either direction, at any time and at any linear position, including when motor 20 is not energized. There is no conversion of rotary motion to linear motion with the concomitant efficiency losses. There are no lead screws, ball screws, or ball bearings to wear out and no lubrication is required.
- Motor 20 can operate in any orientation and is back-driveable (especially at low or zero power input), that is, shaft 30 can be moved by overcoming the magnetic force between the shaft and annular pole plates 64 and 66. Performance of motor 20 can be increased with shorter duty cycles and can be easily constructed for vacuum environments, that is, it can be constructed of materials that do not out gas in a vacuum, the lack of lubrication contributing to this feature. Shaft 30 when hollow allows the pass- through of electrical, optical, and/or fluid lines, and/or the like.
- FIG 8 illustrates a shaft for a linear stepper motor, according to a second embodiment of the present invention, and generally indicated by the reference numeral 200.
- Shaft 200 has impressed thereon a magnetic pattern to permit both linear and rotary motion of the shaft.
- This pattern consists of alternating N and S poles, as at 210 and 212, for linear stepping similar to N and S poles of shaft 30 ( Figure 1).
- stator structure 32 ( Figure 1) in a modular fashion. This permits rotation of shaft 200 or gives additional force to lock shaft 200 in place while linear motion is taking place. Of course, both linear and rotary motion of shaft 200 may be simultaneously realized.
- Figure 9 illustrates a linear motor constructed according to a third embodiment of the present invention, the motor being generally indicated by the reference numeral 300.
- Motor 300 has a metallic base member 310 on which is fixedly disposed an internal stator structure 312 and has a cylindrical, hollow shaft 314 disposed around the stator structure.
- a threaded shaft 320 extends from the upper end of hollow shaft 314 for engagement with other components (not shown).
- Motor 300 is similar to motor 20 ( Figure 1), except that the relative positions of shaft 30 and stator structure 32 are reversed.
- FIG 10 illustrates more clearly the construction of motor 300. It can be seen that hollow shaft 314 moves linearly on the outside of stator structure 312. Additional two-phase stator sections can be axially stacked to increase force.
- motor 300 includes two sleeve bearings 330 and 332.
- Metallic base member 310 provides not only support, but also serves to remove heat from motor 300.
- Figure 11 illustrates hollow shaft 314 and illustrates that it is axially magnetized with alternating N and S poles, as at 340 and 342.
- Figures 12-15 illustrate the components for magnetizing hollow shaft 314, the components being similar to those for magnetizing shaft 30 ( Figures 1 and 3- 5).
- a solid-core copper wire 350 (Figures 14 and 15) is wound in a special pattern on a cylindrical nonconductive mandrel 352 ( Figures 12 and 13) which has grooves, as at 354, machined on its circumference to provide proper spacing and parallelism.
- a larger groove 360 ( Figures 12 and 13) is machined along the length of mandrel 352 and is deeper than grooves 354 to accommodate loop- back sections of wire conductor 350.
- Mandrel 352 is then coated with a non- conductive epoxy, or similar material, and then the outside diameter of the mandrel is final machined to allow hollow shaft (Figure 11) to slide over the mandrel.
- Arrows on Figure 12 indicate the direction of electrical current flow in conductor 350 which creates alternating N and S poles, as at 340 and 342 ( Figure 11) in hollow shaft 314.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2002564817A JP2004521589A (en) | 2001-02-12 | 2002-02-11 | Linear stepper motor, magnetizing device and method |
CA002438229A CA2438229A1 (en) | 2001-02-12 | 2002-02-11 | Linear stepper motor, magnetizing fixture, and methods |
AU2002247171A AU2002247171A1 (en) | 2001-02-12 | 2002-02-11 | Linear stepper motor, magnetizing fixture, and methods |
EP02714940A EP1366555A4 (en) | 2001-02-12 | 2002-02-11 | Linear stepper motor, magnetizing fixture, and methods |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/783,179 | 2001-02-12 | ||
US09/783,179 US6756705B2 (en) | 2000-02-10 | 2001-02-12 | Linear stepper motor |
US28461001P | 2001-04-19 | 2001-04-19 | |
US60/284,610 | 2001-04-19 | ||
US35157302P | 2002-01-28 | 2002-01-28 | |
US60/351,573 | 2002-01-28 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2002065615A2 true WO2002065615A2 (en) | 2002-08-22 |
WO2002065615A3 WO2002065615A3 (en) | 2003-04-17 |
Family
ID=27403473
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2002/005028 WO2002065615A2 (en) | 2001-02-12 | 2002-02-11 | Linear stepper motor, magnetizing fixture, and methods |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP1366555A4 (en) |
JP (1) | JP2004521589A (en) |
AU (1) | AU2002247171A1 (en) |
CA (1) | CA2438229A1 (en) |
TW (1) | TW552766B (en) |
WO (1) | WO2002065615A2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006076900A1 (en) * | 2005-01-22 | 2006-07-27 | Stefan Soter | Linear actuator |
ITBS20090110A1 (en) * | 2009-06-18 | 2010-12-19 | Gimatic Spa | LINEAR ELECTRIC MOTOR |
WO2011127939A1 (en) * | 2010-04-13 | 2011-10-20 | Festo Ag & Co. Kg | Electromagnetic linear direct drive |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4712747B2 (en) * | 2007-03-14 | 2011-06-29 | 三菱電機株式会社 | Magnet magnetizing method for rotor of rotating electrical machine |
WO2009025162A1 (en) * | 2007-08-21 | 2009-02-26 | Kabushiki Kaisha Yaskawa Denki | Cylindrical linear motor armature and cylindrical linear motor |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4504750A (en) * | 1982-04-21 | 1985-03-12 | Matsushita Electric Industrial Co., Ltd. | Linear motor |
US4607197A (en) * | 1978-04-17 | 1986-08-19 | Imc Magnetics Corporation | Linear and rotary actuator |
US5179304A (en) * | 1990-07-26 | 1993-01-12 | Nsk Ltd. | Linear motor system |
US5659280A (en) * | 1996-06-05 | 1997-08-19 | Eastman Kodak Company | Apparatus and system for magnetization of permanent magnet cylinder elements |
US5955798A (en) * | 1995-03-31 | 1999-09-21 | Minolta Co., Ltd. | Linear motor |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4169998A (en) * | 1977-10-03 | 1979-10-02 | Hitachi Metals, Ltd. | Iron core assembly for magnetizing columnar permanent magnets for use in electrostatic developing apparatus |
US4167718A (en) * | 1977-10-03 | 1979-09-11 | Hitachi Metals, Ltd. | Dies set for magnetizing outer surface of magnetic column |
US4168481A (en) * | 1977-10-05 | 1979-09-18 | Hitachi Metals, Ltd. | Core assembly for magnetizing columnar permanent magnet for use in an electrostatic developing apparatus |
JPS62193553A (en) * | 1986-02-18 | 1987-08-25 | Yaskawa Electric Mfg Co Ltd | Linear electromagnetic actuator of permanent magnet type |
JPS63249459A (en) * | 1987-04-02 | 1988-10-17 | Yasushi Okamura | Linear pulse motor |
US4837467A (en) * | 1987-12-02 | 1989-06-06 | North American Philips Corporation | Linear motor with angularly indexed magnetic poles |
JPH05243047A (en) * | 1992-02-28 | 1993-09-21 | Kanegafuchi Chem Ind Co Ltd | Magnetizing mehtod for magnet roll |
JPH06225513A (en) * | 1993-01-20 | 1994-08-12 | Toyota Autom Loom Works Ltd | Linear motor |
-
2002
- 2002-02-11 EP EP02714940A patent/EP1366555A4/en not_active Withdrawn
- 2002-02-11 CA CA002438229A patent/CA2438229A1/en not_active Abandoned
- 2002-02-11 WO PCT/US2002/005028 patent/WO2002065615A2/en not_active Application Discontinuation
- 2002-02-11 JP JP2002564817A patent/JP2004521589A/en not_active Abandoned
- 2002-02-11 AU AU2002247171A patent/AU2002247171A1/en not_active Abandoned
- 2002-02-15 TW TW91102623A patent/TW552766B/en not_active IP Right Cessation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4607197A (en) * | 1978-04-17 | 1986-08-19 | Imc Magnetics Corporation | Linear and rotary actuator |
US4504750A (en) * | 1982-04-21 | 1985-03-12 | Matsushita Electric Industrial Co., Ltd. | Linear motor |
US5179304A (en) * | 1990-07-26 | 1993-01-12 | Nsk Ltd. | Linear motor system |
US5955798A (en) * | 1995-03-31 | 1999-09-21 | Minolta Co., Ltd. | Linear motor |
US5659280A (en) * | 1996-06-05 | 1997-08-19 | Eastman Kodak Company | Apparatus and system for magnetization of permanent magnet cylinder elements |
Non-Patent Citations (1)
Title |
---|
See also references of EP1366555A2 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006076900A1 (en) * | 2005-01-22 | 2006-07-27 | Stefan Soter | Linear actuator |
ITBS20090110A1 (en) * | 2009-06-18 | 2010-12-19 | Gimatic Spa | LINEAR ELECTRIC MOTOR |
WO2011127939A1 (en) * | 2010-04-13 | 2011-10-20 | Festo Ag & Co. Kg | Electromagnetic linear direct drive |
Also Published As
Publication number | Publication date |
---|---|
TW552766B (en) | 2003-09-11 |
WO2002065615A3 (en) | 2003-04-17 |
EP1366555A2 (en) | 2003-12-03 |
JP2004521589A (en) | 2004-07-15 |
CA2438229A1 (en) | 2002-08-22 |
AU2002247171A1 (en) | 2002-08-28 |
EP1366555A4 (en) | 2004-11-03 |
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