US4581553A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brushless DC motor, especially linear motor, having an increased force-to-velocity ratio
Assignee: Individual
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Filing: 1984-04-16
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Granted: 1986-04-08
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Expires: 2004-04-16
Abstract
Abstract A brushless DC motor, most especially a linear motor, has a wound and an unwound part, one part forming the stator and the other the armature, and includes a permanent field magnet arrangement to generate flux and windings linked by the flux. One motor part is provided with a series of flux-conducting portions and the other part is provided with a plurality of flux-carrying portions forming an air gap with the flux-conducting portions. By making the distance from one flux-conducting portion to the next small, and the distance from one flux-carrying portion to the next small, it becomes possible to minimize the distance through which the armature need move to go from a position linking maximum first-polarity flux with a respective winding to a position linking maximum second-polarity flux with that winding. By then providing the flux-carrying portions in an appropriately increased number, to thereby increase the values of the maximum first- and second-polarity linked flux, the force-to-velocity ratio of the motor can be almost arbitrarily increased, this being the equivalent of providing in a rotary motor speed-reducing gearing of high mechanical advantage.
Inventors
- 👤 Helmut Moczala
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:35
CPC Classifications
H; H02; H02K; H02K41/00; H02K41/02; H02K41/03; H02K41/031; H02K41/033; B; B41; B41J; B41J19/00; B41J19/18; B41J19/20; B41J19/30; B41J19/305; H02K2213/00; H02K2213/03
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
393 words
A linear motor, comprising an elongated unwound structural unit of magnetically conductive material, and a wound structural unit, one of said structural units being a stator and the other being an armature that can travel relative to the stator in a travel direction that is the same as the direction of elongation of said elongated unwound structural unit, the wound structural unit comprising permanent-magnet means polarized in direction transverse to the armature travel direction, and the wound structural unit furthermore comprising first and second flux-conducting means made of magnetically conductive material spaced from each other in direction transverse to the armature travel direction, said permanent-magnet means being sandwiched between said first and second flux-conducting means for transmission of the flux of said permanent-magnet means through said first and second flux-conducting means, said first and second flux-conducting means being each formed with respective tooth-groups that are located one after the next in said armature travel direction, with each tooth-group comprising a series of tooth portions that are spaced one from the next in the armature travel direction, said unwound structural unit being formed with a first series of tooth portions spaced one from the next in said armature travel direction and a second series of tooth portions spaced one from the next in said armature travel direction, the first series of tooth portions being spaced from the second series of tooth portions in direction transverse to the armature travel direction, the wound structural unit being so located relative to the unwound structural unit that the tooth-groups of the first flux-conducting means form a first air gap with said first series of tooth portions, and the tooth-groups of the second flux-conducting means form a second air gap with said second series of tooth portions, whereby flux emanating from said permanent-magnet means is constrained to cross both the first and the second air gap in order to return to said permanent-magnet means, the tooth-groups of the first flux-conducting means including tooth-groups that are differently phased relative to each other, and the tooth-groups of the second flux-conducting means including tooth-groups that are differently phased relative to each other, the wound structural unit furthermore comprising first coil means wound around said first flux-conducting means but not around said second flux-conducting means, and second coil means wound around said second flux-conducting means but not around said first flux-conducting means.
Claim 2
Dependent Claim
393 words
A linear motor, comprising an elongated unwound structural unit of magnetically conductive material, and a wound structural unit, one of said structural units being a stator and the other being an armature that can travel relative to the stator in a travel direction that is the same as the direction of elongation of said elongated unwound structural unit, the wound structural unit comprising permanent-magnet means polarized in direction transverse to the armature travel direction, and the wound structural unit furthermore comprising first and second flux-conducting means made of magnetically conductive material spaced from each other in direction transverse to the armature travel direction, said permanent-magnet means being sandwiched between said first and second flux-conducting means for transmission of the flux of said permanent-magnet means through said first and second flux-conducting means, said first and second flux-conducting means being each formed with respective tooth-groups that are located one after the next in said armature travel direction, with each tooth-group comprising a series of tooth portions that are spaced one from the next in the armature travel direction, said unwound structural unit being formed with a first series of tooth portions spaced one from the next in said armature travel direction and a second series of tooth portions spaced one from the next in said armature travel direction, the first series of tooth portions being spaced from the second series of tooth portions in direction transverse to the armature travel direction, the wound structural unit being so located relative to the unwound structural unit that the tooth-groups of the first flux-conducting means form a first air gap with said first series of tooth portions, and the tooth-groups of the second flux-conducting means form a second air gap with said second series of tooth portions, whereby flux emanating from said permanent-magnet means is constrained to cross both the first and the second air gap in order to return to said permanent-magnet means, the tooth-groups of the first flux-conducting means including tooth-groups that are differently phased relative to each other, and the tooth-groups of the second flux-conducting means including tooth-groups that are differently phased relative to each other, the wound structural unit furthermore comprising first coil means wound around said first flux-conducting means but not around said second flux-conducting means, and second coil means wound around said second flux-conducting means but not around said first flux-conducting means.
Claim 3
Dependent Claim
26 words
A motor as defined in claim 1, said first and second coil means comprising coils having longitudinal axes that extend parallel to the armature travel direction.
Claim 4
Dependent Claim
42 words
A motor as defined in claim 2, the first and second flux-conducting means each having a total of two tooth-groups, the first and second coil means each consisting of a single coil located intermediate the two tooth-groups of the respective flux-conducting means.
Claim 5
Dependent Claim
50 words
A motor as defined in claim 3, the tooth portions of said first and second series of tooth portions all having end faces located in a single plane, the tooth portions of the tooth-groups of said first and second flux-conducting means all having end faces located in a single plane.
Claim 6
Dependent Claim
97 words
A motor as defined in claim 3, said permanent-magnet means comprising two permanent-magnet units of which both are polarized transverse to the armature travel direction, the two permanent-magnet units being spaced one from the other in the armature travel direction, with each permanent-magnet unit having in the armature travel direction a length substantially corresponding to the length of a tooth-group, the two permanent-magnet units being spatially separated from each other in the armature travel direction to leave therebetween a space that accommodates a portion of the first coil means and a portion of the second coil means.
Claim 7
Dependent Claim
42 words
A motor as defined in claim 5, the motor furthermore comprising position-detecting means for detecting the position of the wound and unwound structural units relative to each other and for generating signals indicative of such relative position useful for commutating the motor.
Claim 8
Dependent Claim
26 words
A motor as defined in claim 6, the position-detecting means comprising means located to sense the magnetic flux in at least one of said air gaps.
Claim 9
Dependent Claim
24 words
A motor as defined in claim 5, wherein the tooth-length of the tooth portions is about 1 mm measured in the armature travel direction.
References Cited (Backward Citations)
US4370577A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-07 | 1989-10-07 | 1990-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-07 | 1993-10-07 | 1994-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-07 | 1997-10-07 | 1998-04-08 | $7700.00 | Window Closed / Lapsed |