US3922590A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical systems and apparatus
Assignee: Mettoy Co Ltd
•
Filing: 1973-04-20
•
Granted: 1975-11-25
•
Expires: 1993-04-20
Abstract
Abstract An electric motor comprises a permanent magnet rotor having a ring of material containing permanent magnetic material bonded by a plastic material magnetised to provide a number of magnetic poles of alternately opposite polarity and a stator with associated winding arranged to produce magnetic stator poles which co-operate with the magnetic poles of the rotor to drive said rotor. A reed switch is provided for sensing the speed of rotation of the rotor to provide a signal which is used to control the speed of the motor. Preferably, the stator is situated opposite a portion only of the circumference of the ring of material containing permanent magnetic material.
Inventors
- 👤 Anthony Charles Warren
- 👤 Bryan Frederick Nicholls
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:45
CPC Classifications
H; H02; H02K; H02K21/00; H02K21/12; H02K21/22; H02K29/00; H02K29/06; H02K2201/00; H02K2201/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
200 words
An electric motor comprising a rotor mounted for rotation about an axis and including a ring of material containing permanent magnetic material bonded by a plastics material to provide a number of magnetic poles of alternately opposite polarity disposed annularly about the axis of rotation of the rotor; a stator assembly comprising a coil and two plates of magnetic material containing therebetween said coil, each plate having one edge provided with fingers forming stator pole faces, and the fingers of the plate being interdigitated whereby, when the coil is energised, stator poles of alternately opposite polarity are produced which co-operate with the magnetic poles of the rotor to drive the motor, said edge being situated opposite a portion only of the circumference of the ring of permanent magnetic material; rotor position sensor means disposed adjacent the ring of permanent magnetic material in a position displaced from the stator assembly in a direction peripheral of said rotor and arranged to respond to the poles of the rotor during rotation to derive an electrical signal in accordance with the rotation of the rotor; and control means responsive to said signal for controlling energisation of said coil and the rotation of the rotor.
Claim 2
Dependent Claim
200 words
An electric motor comprising a rotor mounted for rotation about an axis and including a ring of material containing permanent magnetic material bonded by a plastics material to provide a number of magnetic poles of alternately opposite polarity disposed annularly about the axis of rotation of the rotor; a stator assembly comprising a coil and two plates of magnetic material containing therebetween said coil, each plate having one edge provided with fingers forming stator pole faces, and the fingers of the plate being interdigitated whereby, when the coil is energised, stator poles of alternately opposite polarity are produced which co-operate with the magnetic poles of the rotor to drive the motor, said edge being situated opposite a portion only of the circumference of the ring of permanent magnetic material; rotor position sensor means disposed adjacent the ring of permanent magnetic material in a position displaced from the stator assembly in a direction peripheral of said rotor and arranged to respond to the poles of the rotor during rotation to derive an electrical signal in accordance with the rotation of the rotor; and control means responsive to said signal for controlling energisation of said coil and the rotation of the rotor.
Claim 3
Dependent Claim
29 words
An electric motor according to claim 1, wherein the rotor is moulded from plastics material, the ring of permanent magnetic material being moulded in or integral with the rotor.
Claim 4
Dependent Claim
17 words
An electric motor according to claim 1, wherein the rotor position sensor means is a reed switch.
Claim 5
Dependent Claim
16 words
An electric motor according to claim 3, and comprising magnetic biasing means for said reed switch.
Claim 6
Dependent Claim
67 words
An electric motor according to claim 1 wherein said control means comprises a comparator to which said electrical signal is applied, reference signal source means for applying said reference signal to said comparator, said comparator being arranged to produce a difference signal, corresponding to the difference between the said signals applied thereto, and means for controlling the energisation of said winding in accordance with said difference signal.
Claim 7
Dependent Claim
16 words
An electric motor according to claim 5, wherein said reference signal source is an oscillator circuit.
Claim 8
Dependent Claim
44 words
An electric motor according to claim 6, wherein said winding has two sections, said motor including a d.c. supply two semiconductor switch means arranged to connect said winding sections alternately across said supply, and means controlled by said oscillator for controlling said switches alternately.
Claim 9
Dependent Claim
25 words
An electric motor according to claim 1 and comprising a plurality of stator sections, said stators being displaced in a direction peripheral of said rotor.
References Cited (Backward Citations)
US3230434A
Cited
US3331005A
Cited
US3683248A
Cited
US3586942A
Cited
US3634873A
Cited
US3678359A
Cited
US3706923A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |