US3980913A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic speed sensor
Assignee: Bendix Corp
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Filing: 1975-03-20
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Granted: 1976-09-14
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Expires: 1995-03-20
Abstract
Abstract A device for providing signals corresponding to rotation of a body having a magnetic sensor with a sensing pole positioned proximate to a tone wheel rotated by the rotating body. A permanent magnet is attached to the sensing pole and a signal voltage having a frequency proportional to the speed of the rotating body is induced in a coil surrounding the sensing pole. The sensing pole is made of square loop magnetic material and is shaped and arranged to cause the magnetomotive force difference between its pole face and the tone wheel to decrease as the air gap length between them decreases, thus causing the normally large change in sensor output with air gap length variation to be substantially reduced.
Inventors
- 👤 Arnold Duane Peterson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:24
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/48; G01P3/481; G01P3/488
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
104 words
A device for providing signals corresponding to rotation of a rotating body, comprising a tone wheel rotated by the rotating body, a magnetic sensor having a sensing pole proximate the tone wheel, coil means surrounding the sensing pole, means for magnetizing the sensing pole to induce a signal voltage in the coil means corresponding to the rotation of the rotating body, and means for automatically controlling the magnetomotive force gradient between the sensing pole and the tone wheel to minimize variations in signal voltage amplitude normally caused by variations in the length of the air gap between the sensing pole and the tone wheel.
Claim 2
Independent Claim
104 words
A device for providing signals corresponding to rotation of a rotating body, comprising a tone wheel rotated by the rotating body, a magnetic sensor having a sensing pole proximate the tone wheel, coil means surrounding the sensing pole, means for magnetizing the sensing pole to induce a signal voltage in the coil means corresponding to the rotation of the rotating body, and means for automatically controlling the magnetomotive force gradient between the sensing pole and the tone wheel to minimize variations in signal voltage amplitude normally caused by variations in the length of the air gap between the sensing pole and the tone wheel.
Claim 3
Dependent Claim
54 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 1 in which the means for controlling the magnetomotive force gradient between the sensing pole and the tone wheel includes means for providing a magnetomotive force drop across the sensing pole which varies inversely with the air gap.
Claim 4
Dependent Claim
83 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 2 in which the means for controlling the magnetomotive force gradient between the sensing pole and tone wheel includes shaping and sizing the cross-section of the sensing pole to provide substantially constant flux density just below the "knee" of its d.c. magnetization curve throughout substantially the entire length of the sensing pole when the tone wheel is in the inregister position and the air gap is maximum.
Claim 5
Dependent Claim
38 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 3, in which the sensing pole is made of material having a direct current magnetization curve with a sharp "knee" at saturation.
Claim 6
Dependent Claim
29 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 4, in which the sensing pole is made of square loop magnetic material
Claim 7
Dependent Claim
30 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 5, in which the means for magnetizing the sensing pole is a permanent magnet.
Claim 8
Dependent Claim
42 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 6, having a Ferromagnetic flux return member to provide a high permeance flux path from the magnetic pole opposite the sensing pole to the tone wheel.
Claim 9
Dependent Claim
27 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 7, in which the flux return member has a U-shaped configuration.
Claim 10
Dependent Claim
47 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 7, in which the sensing pole is connected to one pole of the permanent magnet and the ferromagnetic flux return member is attached to the other pole of the permanent magnet.
Claim 11
Dependent Claim
38 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 5, in which the sensing pole has a tapered body profile and a tip of substantially constant dimensions attached to the body.
Claim 12
Dependent Claim
54 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 10, in which the sensing pole cross-section is of a size and profile to provide a uniform D.C. pole flux density which is just below the "knee" of its D.C. magnetization under the maximum operating air gap condition.
Claim 13
Dependent Claim
36 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 11, having means connected in series with the magnetic circuit to minimize changes in signal amplitude with changes in temperature.
Claim 14
Dependent Claim
45 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 12, in which the means for minimizing changes in signal amplitude with changes in temperature is a Curie metal element connected in series with the working gap magnetic circuit.
Claim 15
Dependent Claim
33 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 13, in which the Curie metal element is positioned between the sensing pole and the permanent magnet.
Claim 16
Dependent Claim
34 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 9, having an element of Curie metal positioned between the permanent magnet and the ferromagnetic flux return member.
Claim 17
Dependent Claim
40 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 13, in which the tip of the sensing pole is formed of Curie metal to minimize changes in signal amplitude with changes in temperature.
Claim 18
Dependent Claim
32 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 13, in which at least a portion of the tone wheel is made of Curie metal.
Claim 19
Dependent Claim
34 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 9, in which at least a portion of the ferromagnetic flux return member is made of Curie metal.
Claim 20
Dependent Claim
45 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 11, in which the permanent magnet is of magnetic material having a large reversible temperature coefficient of induction to provide decreasing air gap magnetomotive force with increasing operating temperature.
Claim 21
Dependent Claim
45 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 6, in which the permanent magnet is of magnetic material having a large reversible temperature coefficient of induction to provide decreasing air gap magnetomotive force with increasing operating temperature.
Claim 22
Dependent Claim
36 words
A device for providing signals corresponding to rotation of a rotating body as described in claim 5, having means connected in series with the magnetic circuit to minimize changes in signal amplitude with changes in temperature.
References Cited (Backward Citations)
US1977600A
Cited
US2718603A
Cited
US3158033A
Cited
US3230407A
Cited
US3252024A
Cited
US3793545A
Cited
US3738175A
Cited
US3876927A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-14 | 1980-03-15 | 1980-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-14 | 1984-03-15 | 1984-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-14 | 1988-03-15 | 1988-09-14 | $7700.00 | Window Closed / Lapsed |