Patent US4783768A successfully refreshed from Google Patents.
Patent US4319153A successfully refreshed from Google Patents.
US4319153A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric motor with controllable mechanical wear and spark generation
Assignee: Mabuchi Motor Co Ltd
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Filing: 1979-04-04
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Granted: 1982-03-09
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Expires: 1999-04-04
Abstract
Abstract A small electric motor having a plurality of commutator arcuate segments equally spaced in the direction of angular position on the rotating shaft of motor rotor, wherein conductive grease is coated on the commutator arcuate segments and the equally spaced gaps, and edges provided on the sliding portions of brushes are caused to press and contact the commutator by cutting the conductive grease film.
Inventors
- 👤 Takaichi Mabuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:58
CPC Classifications
H; H01; H01R; H01R39/00; H01R39/02; H01R39/56
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
117 words
In electric motor with controllable mechanical and electrical wear and comprising a central rotor shaft, an insulating cylinder surrounding said shaft, a commutator surrounding said cylinder and having a plurality of conductive arcuate segments, each of said segments being equally spaced from the adjoining ones by a gap, and a plurality of metal brushes having sliding edges in tangential pressure contact with said arcuate segments, the improvement characterized by an electrically conductive spark-quenching grease coating the outer surface of said arcuate segments and filling said gaps whereby mechanical wear caused by excessive pressure of said brushes on said commutator and spark generation caused by insufficient pressure of said brushes are concurrently and controllably reduced by said grease.
Claim 2
Dependent Claim
117 words
In electric motor with controllable mechanical and electrical wear and comprising a central rotor shaft, an insulating cylinder surrounding said shaft, a commutator surrounding said cylinder and having a plurality of conductive arcuate segments, each of said segments being equally spaced from the adjoining ones by a gap, and a plurality of metal brushes having sliding edges in tangential pressure contact with said arcuate segments, the improvement characterized by an electrically conductive spark-quenching grease coating the outer surface of said arcuate segments and filling said gaps whereby mechanical wear caused by excessive pressure of said brushes on said commutator and spark generation caused by insufficient pressure of said brushes are concurrently and controllably reduced by said grease.
Claim 3
Dependent Claim
90 words
The electric motor as set forth in claim 1 wherein the conductive grease is free of metallic powders, carbon, graphite and other conductive fine particles and can be characterized by the following properties: an electrical resistance value of about 35 kΩ-Cm, a visual appearance of milky brown butter, a consistency of 350 at 25° C., the absence of dripping at any temperature, the absence of oil-separation, a resistance to the copper corrosion test at 100° C. for 24 hours, an operating temperature range of from -20° C. to 180° C.
Claim 4
Dependent Claim
21 words
The electric motor as set forth in claim 1 wherein the conductive grease contains carbon, graphite and other conductive fine particles.
Claim 5
Dependent Claim
23 words
The electric motor as set forth in claim 3, wherein the conductive grease has an electrical resistance of not more than 4 kΩ/cm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-03-08 | 1985-09-07 | 1986-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-03-08 | 1989-09-07 | 1990-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-03-08 | 1993-09-07 | 1994-03-09 | $7700.00 | Window Closed / Lapsed |