Patent US3284241A successfully refreshed from Google Patents.
Patent US3924148A successfully refreshed from Google Patents.
US3924148A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Small size DC motors
Assignee: Mitsubishi Mining and Cement Co Ltd
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Filing: 1973-11-01
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Granted: 1975-12-02
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Expires: 1993-11-01
Abstract
Abstract New small size DC motors comprising as a spark suppressing element a commutator composed of a cylinder-shaped oxide sintered body having a remarkably stable volt-ampere characteristic as a parent body of the commutator and a plurality of metal or alloy pieces as the commutator segments are provided. The spark suppressing element utilizes an electric barrier existing at the contact surface between the oxide sintered body and the metal or alloy pieces, and can suppress the generation of spark between the commutator and the brush completely, thereby making the motor long-lived and also noiseless. Further, this element is easily to be attached and inexpensive in manufacturing cost.
Inventors
- 👤 Kan-Ichi Tachibana
- 👤 Michihiro Nishioka
- 👤 Mikiya Ono
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:23
CPC Classifications
H; H02; H02K; H02K13/00; H02K13/006; H02K13/10; H02K13/105
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
92 words
A small size DC motor comprising a commutator composed of a cylinder-shaped oxide sintered body having a barrier resistance at its surface, said oxide sintered body having negative resistance and also possessing the resistivity R0K Omega cm at 273*K and the thermistor constant B*K that satisfy the relation R0 X B < OR = 10,000 K Omega cm.*K, and metal or alloy pieces attached to the plural points of the surface of said cylindershaped oxide sintered body respectively, said metal or alloy pieces being highly anticorrosive and having a high electric conductivity.
Claim 2
Dependent Claim
92 words
A small size DC motor comprising a commutator composed of a cylinder-shaped oxide sintered body having a barrier resistance at its surface, said oxide sintered body having negative resistance and also possessing the resistivity R0K Omega cm at 273*K and the thermistor constant B*K that satisfy the relation R0 X B < OR = 10,000 K Omega cm.*K, and metal or alloy pieces attached to the plural points of the surface of said cylindershaped oxide sintered body respectively, said metal or alloy pieces being highly anticorrosive and having a high electric conductivity.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |