US4823620A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetostrictive device for measuring torsional torque
Assignee: Nissan Motor Co Ltd
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Filing: 1987-02-05
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Granted: 1989-04-25
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Expires: 2007-02-05
Abstract
Abstract In a device for measuring torsional torque applied to a fixed or revolving shaft made of a magnetic material by producing a magnetic circuit in which the flux path includes a section of the shaft and detecting a magnetostrictive change induced by the torque, the surface of said section of the shaft is formed with a series of parallel grooves and/or lands or protuberances inclining at a suitable angle with the longitudinal axis of the shaft to thereby cause magnetic flux in the surface layer of the shaft to extend approximately in the direction of tensile or compressive stress produced by the torque. It is preferred to form a first series of parallel grooves extending spirally and inclining 45° with said axis in one section of the shaft and a second series of parallel and spiral grooves inclining 45° with said axis and reverse to the first series of grooves in another section of the shaft to detect a difference between magnetostrictive changes in the respective sections.
Inventors
- 👤 Shouichi Edo
- 👤 Hiroyuki Aoki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:34
CPC Classifications
G; G01; G01L; G01L3/00; G01L3/02; G01L3/04; G01L3/10; G01L3/101; G01L3/102; G01L3/105
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
174 words
A device for measuring torsional torque applied to a shaft made of a magnetic material at least in a surface region thereof, the device comprising: an exciting coil positioned close to the shaft so as to produce a magnetic circuit in which the magnetic flux path includes a selected section of the shaft; detection means for detecting a magnetostrictive change induced in said section of the shaft by torsional torque applied to the shaft; and flux directioning means for differentiating the level of the surface of the shaft in a series of elongate and parallel regions of said section, said flux directioning means being integral with the shaft, said elongate and parallel regions being inclined at a predetermined angle with the longitudinal axis of the shaft, wherein said flux directioning means comprises a series of elongate and parallel grooves formed in the surface of said section of the shaft and inclined at said predetermined angle, wherein the surface region of the shaft is carburized at least in said selected section after forming said grooves.
Claim 2
Independent Claim
174 words
A device for measuring torsional torque applied to a shaft made of a magnetic material at least in a surface region thereof, the device comprising: an exciting coil positioned close to the shaft so as to produce a magnetic circuit in which the magnetic flux path includes a selected section of the shaft; detection means for detecting a magnetostrictive change induced in said section of the shaft by torsional torque applied to the shaft; and flux directioning means for differentiating the level of the surface of the shaft in a series of elongate and parallel regions of said section, said flux directioning means being integral with the shaft, said elongate and parallel regions being inclined at a predetermined angle with the longitudinal axis of the shaft, wherein said flux directioning means comprises a series of elongate and parallel grooves formed in the surface of said section of the shaft and inclined at said predetermined angle, wherein the surface region of the shaft is carburized at least in said selected section after forming said grooves.
Claim 3
Dependent Claim
12 words
A device according to claim 1, wherein said angle is approximately 45°.
Claim 4
Dependent Claim
42 words
A device according to claim 1, wherein said elongate and parallel regions are distributed such that any line segment drawn parallel to the longitudinal axis of the shaft on the surface of said section of the shaft intersects said flux directioning means.
Claim 5
Dependent Claim
30 words
A device according to claim 1, wherein said flux directioning means further comprises a series of parallel lands, each of which is bordered by any adjacent two of said grooves.
Claim 6
Dependent Claim
43 words
A device according to claim 1, wherein said grooves are shaped and distributed such that any line segment drawn parallel to the longitudinal axis of the shaft on the surface of said section of the shaft intersects at least one of said grooves.
Claim 7
Dependent Claim
93 words
A device according to claim 1, further comprising another exciting coil positioned close to the shaft so as to produce a magnetic circuit in which the magnetic flux path includes another section of the shaft, and another series of elongate and parallel grooves formed in said another section and inclined in reverse to said series of grooves in said selected section at said predetermined angle with the longitudinal axis of the shaft, said detection means comprising means for detecting a magnetostrictive change induced in said another section of the sahft by said torque.
Claim 8
Dependent Claim
50 words
A device according to claim 6, wherein said detection means further comprises an electric circuit which comprises an AC bridge circuit wherein said exciting coil and said another exciting coil constitute two adjacent arms thereof for detecting magnetostrictive changes induced in said section and said another section of the shaft.
Claim 9
Dependent Claim
36 words
A device according to claim 1, wherein said series of grooves in said selected section and said another series of elongate and parallel grooves are substantially symmetrical with respect to a plane cross-sectional of the shaft.
Claim 10
Independent Claim
174 words
A device for measuring torsional torque applied to a shaft made of a magnetic material at least in a surface region thereof, the device comprising: an exciting coil positioned close to the shaft so as to produce a magnetic circuit in which the magnetic flux path includes a selected section of the shaft; detection means for detecting a magnetostrictive change induced in said section of the shaft by torsional torque applied to the shaft; and flux directioning means for differentiating the level of the surface of the shaft in a series of elongate and parallel regions of said section, said flux directioning means being integral with the shaft, said elongate and parallel regions being inclined at a predetermined angle with the longitudinal axis of the shaft, wherein said flux directioning means comprises a series of elongate and parallel grooves formed in the surface of said section of the shaft and inclined at said predetermined angle, wherein the surface region of the shaft is hardened at least in said selected section after forming said grooves.
Claim 11
Independent Claim
174 words
A device for measuring torsional torque applied to a shaft made of a magnetic material at least in a surface region thereof, the device comprising: an exciting coil positioned close to the shaft so as to produce a magnetic circuit in which the magnetic flux path includes a selected section of the shaft; detection means for detecting a magnetostrictive change induced in said section of the shaft by torsional torque applied to the shaft; and flux directioning means for differentiating the level of the surface of the shaft in a series of elongate and parallel regions of said section, said flux directioning means being integral with the shaft, said elongate and parallel regions being inclined at a predetermined angle with the longitudinal axis of the shaft, wherein said flux directioning means comprises a series of elongate and parallel grooves formed in the surface of said section of the shaft and inclined at said predetermined angle, wherein the surface region of the shaft is hardened at least in said selected section after forming said grooves.
Claim 12
Dependent Claim
12 words
A device according to claim 9, wherein said angle is approximately 45°.
Claim 13
Dependent Claim
30 words
A device according to claim 9, wherein said flux directioning means further comprises a series of parallel lands each of which is bordered by any adjacent two of said grooves.
Claim 14
Dependent Claim
46 words
A device according to claim 9, wherein said grooves are shaped and distributed such that any line segment drawn parallel to the longitudinal axis of the shaft on the surface of said section of the shaft intersects at least one of said elongate and parallel grooves.
Claim 15
Dependent Claim
93 words
A device according to claim 9, further comprising another exciting coil positioned close to the shaft so as to produce a magnetic circuit in which the magnetic flux path includes another section of the shaft, and another series of elongate and parallel grooves formed in said another section and inclined in reverse to said series of grooves in said selected section at said predetermined angle with the longitudinal axis of the shaft, said detection means comprising means for detecting a magnetostrictive change induced in said another section of the shaft by said torque.
Claim 16
Dependent Claim
38 words
A device according to claim 13, wherein said series of elongate and parallel grooves in said selected section and another series of elongate and parallel grooves are substantially symmetrical with respect to a plane cross-sectional of the shaft.
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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) | 1992-04-24 | 1992-10-24 | 1993-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-24 | 1996-10-24 | 1997-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-24 | 2000-10-24 | 2001-04-25 | $7700.00 | Window Closed / Lapsed |