US3845335A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electromagnetic stepping micromotor
Assignee: Centre Electronique Horloger SA
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Filing: 1973-08-06
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Granted: 1974-10-29
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Expires: 1993-08-06
Abstract
Abstract An electromagnetic stepping micromotor includes a rotor formed by a flat disc of high-coercivity ferromagnetic material having n radially projecting angularly separated teeth all magnetized in a like axial direction. A stator includes two coplanar parts of soft ferromagnetic material, an inner part having n outwardly projecting teeth and an outer part having n inwardly projecting teeth, imbricated in one another and separated by a relatively narrow air-gap having 2n radially extending portions. The rotor is mounted between said coplanar parts of the stator and a cover having 2n selectively disposed apertures providing variations in reluctance defining 2n angularly stable positions of the rotor. The stator also includes a core with a second cover completing the magnetic circuit between the coplanar parts, and a coil supplied with bipolar clock pulses for driving the rotor.
Inventors
- 👤 H Oguey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:36
CPC Classifications
G; G04; G04C; G04C13/00; G04C13/08; G04C13/10; G04C13/11; H; H02; H02K; H02K37/00; H02K37/02; H02K37/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
115 words
Electromagnetic stepping micromotor for timepieces comprising a rotor in the form of at least one disc having magnetized parts and a stator of soft ferromagnetic material having two parts presenting a coplanar surface towards the rotor, the parts being separated from each other by a sinuous air-gap, wherein the rotor is flat and includes at least one wheel having a plurality of teeth equidistant from each other, said teeth being axially magnetized in the same direction, the air-gap of the stator being narrow in relation to the width of the teeth of the rotor and presenting a number of radial segments equiangularly equidistant from each other and equal to twice the number of rotor teeth.
Claim 2
Dependent Claim
115 words
Electromagnetic stepping micromotor for timepieces comprising a rotor in the form of at least one disc having magnetized parts and a stator of soft ferromagnetic material having two parts presenting a coplanar surface towards the rotor, the parts being separated from each other by a sinuous air-gap, wherein the rotor is flat and includes at least one wheel having a plurality of teeth equidistant from each other, said teeth being axially magnetized in the same direction, the air-gap of the stator being narrow in relation to the width of the teeth of the rotor and presenting a number of radial segments equiangularly equidistant from each other and equal to twice the number of rotor teeth.
Claim 3
Dependent Claim
26 words
Micromotor according to claim 1, comprising means for defining a number of angularly stable positions of the rotor equal to twice the number of rotor teeth.
Claim 4
Dependent Claim
47 words
Micromotor according to claim 2, in which said means comprises an auxiliary plate of soft ferromagnetic material fixed to the stator parallel to the plane of said coplanar parts of the stator, said plate being provided periodic variations of reluctance corresponding to said number of stable positions.
Claim 5
Dependent Claim
25 words
Micromotor according to claim 1, in which said two coplanar parts of the stator are held together in the same plane by non-magnetic joining elements.
Claim 6
Dependent Claim
50 words
Micromotor according to claim 1, in which the stator exerts on the rotor an axial force greater than the weight of the rotor, and in which the rotor is pivotally mounted about a pin fixed to said stator, said pin including means for limiting the axial position of the rotor.
Claim 7
Dependent Claim
30 words
Micromotor according to claim 5, in which the stator includes at its outer periphery arcuate edges defining means for centering the stator, said arcuate edges being coaxial with said pin.
Claim 8
Dependent Claim
38 words
Micromotor according to claim 1, in which the rotor comprises first and second toothed wheels the teeth of which are imbricated in one another, the teeth of the first and second wheels being axially magnetized in opposite directions.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |