GB2273568A - Position transducer - Google Patents
Position transducer Download PDFInfo
- Publication number
- GB2273568A GB2273568A GB9226480A GB9226480A GB2273568A GB 2273568 A GB2273568 A GB 2273568A GB 9226480 A GB9226480 A GB 9226480A GB 9226480 A GB9226480 A GB 9226480A GB 2273568 A GB2273568 A GB 2273568A
- Authority
- GB
- United Kingdom
- Prior art keywords
- core
- magnetic field
- position transducer
- external magnetic
- transducer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
- G01D5/2006—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils
- G01D5/2033—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils controlling the saturation of a magnetic circuit by means of a movable element, e.g. a magnet
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
- G01D5/2006—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils
- G01D5/2013—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils by a movable ferromagnetic element, e.g. a core
Abstract
A position transducer comprises a core 10 preferably of a ferromagnetic amorphous alloy, a permanent magnet 20 or electromagnet subjecting the core 10 to an external magnetic field, and a tapered shield 30 movable in the gap between the magnet 20 and core 10 to modify the strength of the field to which the core is subjected depending on the (e.g. rotary) position of a movable element. The core 10 is wound with primary and secondary windings: the current induced in the secondary, by a.c. in the primary, depends on the strength of the magnetic field acting on the core and therefore on the position of the movable element. The shield 30 is of soft magnetic material. Alternatively the movable element may be coupled to the magnet 20 or other field producing device. The core 10 is preferably of tubular form with toroidal windings. <IMAGE>
Description
Position Transducer
This invention relates to a transducer for determining the position of an element relative to the transducer, and particularly, but not solely, relates to a transducer for determining the angular position of an element which is rotatable relative to the transducer.
A wide variety of position detecting transducers are known but many of these, particularly transducers for determining the angular position of a rotatable element, involve physical contact and therefore exhibit the drawbacks of friction and wear. We have now devised a non-contact position detecting transducer which is of relatively simple but robust construction and which is accurate and reliable in use.
In accordance with this invention, there is provided a position transducer which comprises a core, primary and secondary windings wound on the core, and means for generating an external magnetic field, the core being disposed within said magnetic field, the transducer being arranged such that movement of an element, the position of which is to be determined, modifies the effect of the external magnetic field on the core and the voltage across the secondary coil represents the position of that element.
The external magnetic field is preferably unidirectional and may be provided by a permanent magnet or by an electromagnetic coil. Preferably the magnetic field subjects the core to a biassing but non-saturating field, preferably providing an operating point on a linear part of the hysteresis curve of the core.
Movement of the element, the position of which is to be determined, may effect movement of the magnetic field generating means relative to the core, thus modifying the strength of the field to which the core is subjected.
Alternatively, movement of the element, the position of which is to be determined, may effect movement of a shield in a space between the magnetic field generating means and the core, so that the core is shielded from the magnetic field to a greater or lesser extent depending upon the position of the moveable element. For example, the shield may have a tapered shape.
Preferably the core is formed of a ferromagnetic amorphous alloy. Typical such alloys follow the atomic composition formula Tx M1 xt where T represents one or more of the transition elements iron (Fe), nickel (Ni) or cobalt (Co) and M represents one or more of the metalloid or glass-formerelements phosphorus (P), boron (B), carbon (C) or silicon (Si).
The transition metal content x is usually in the range 75 to 86%. Such ferromagnetic amorphous alloys exhibit particularly high magnetic permeability.
The transducer in accordance with this invention may be arranged to respond to linear or to rotary displacement of the movable element relative to the core.
The transducer in accordance with this invention may be used, for example, in a variety of applications in automobiles.
An embodiment of this invention will now be described by way of example only and with reference to the accompanying drawing, the single figure of which is a schematic view of a rotary position transducer in accordance with the invention.
Referring to the drawing, there is shown a rotary position transducer which comprises a core 10 in the form of a tube of ferromagnetic material. The core may be made by wrapping a ribbon of ferromagnetic amorphous alloy into tubular shape. The core has primary and secondary coils (not shown) wound onto it to form a toroid-like structure. The core is subjected to a non-saturating, unidirectional magnetic field, extending radially of the core, by an external ferrite permanent magnet 20.
A shield 30 of soft magnetic material is movable in the gap between the permanent magnet 20 and the core 10. The shield 30 tapers in height from one end to the other, and is bent into arcuate form: it is positioned in the gap between the core 10 and the magnet 20, to lie on the surface of an imaginary cylinder encircling the tubular core 10. The shield is rotatable around its axis and is mechanically coupled to an angularly-displaceable element, the angular position of which is to be determined.
It will be appreciated that the strength of the external magnetic field, to which the core 10 is subjected, will depend upon the angular position of the shield 30 and hence upon the width of the shield intersecting the plane containing the axis of the core and parallel to the magnetic field. An alternating current is passed through the primary winding on the core and a voltage is therefore induced in the secondary coil: however, the magnitude of the voltage across the secondary coil varies depending on the strength of the magnetic field acting on the core and hence upon the angular position of the shield.
The external magnetic field subjects the core to a biassing but non-saturating field, preferably providing an operating point on a linear part of the hysteresis curve of the core.
In an alternative arrangement, the shield 30 remains stationary and the permanent magnet 20 is mechanically connected to the element, the position of which is to be determined, so as to move along a circular path coaxial with the core 10.
It will be appreciated that whilst a rotary displacement transducer has been described, the device can be modified to determine linear displacement. For example, a linearly-displaceable element, the linear position of which is to be determined, is mechanically connected to the shield 30 to produce rotary movement of the latter, or the tapered shield may be in flat form and arranged to displace linearly in the gap between the external magnetic and the core. Further, instead of providing the shield, the permanent magnet may be arranged to move e.g. towards or away from the core according to a linear or rotary displacement of the movable element to be monitored, thus similarly modifying the magnetic field to which the core is subjected.
The transducer may be provided with an outer shield to prevent it being affected by stray or unwanted external magnetic fields, e.g. if the transducer is to be used in hostile environments.
Claims (13)
1) A position transducer which comprises a core, primary and secondary windings wound on the core, and means for generating an external magnetic field, the core being disposed within said magnetic field, the transducer being arranged such that movement of an element, the position of which is to be determined, modifies the effect of the external magnetic field on the core and the voltage across the secondary coil represents the position of that element.
2) A position transducer as claimed in claim 1, in which the means for generating the external magnetic field comprises a permanent magnet.
3) A position transducer as claimed in claim 1, in which the means for generating the external magnetic field comprises an electromagnetic coil.
4) A position transducer as claimed in any preceding claim, in which the external magnetic field subjects the core to a biassing but non-saturating field.
5) A position transducer as claimed in any preceding claim, in which the core has a tubular shape and the primary and secondary coils are wound onto the core to--form a toroidal arrangement.
6) A position transducer as claimed in claim 5, in which the external magnetic field extends in a generally radial direction relative to said core.
7) A position transducer as claimed in claim 5 or 6, in which the core comprises a ferromagnetic amorphous alloy.
8) A position transducer as claimed in any preceding claim, comprising a shield of magnetically permeable material movable in a gap between the core and external magnetic field, to shield the core to a greater or lesser degree depending upon its position.
9) A position transducer as claimed in claim 8, in which the shield has a tapered shape.
10) A position transducer as claimed in any one of claims 1 to 7, in which the external magnetic field generating means is movable towards or away from the core with movement of the movable element.
11) A position transducer as claimed in any preceding claim, arranged to determine the angular position of said movable element.
12) A position transducer as claimed in any one of claims 1 to 10, arranged to determine the linear position of said movable element.
13) A position transducer substantially as herein described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9226480A GB2273568A (en) | 1992-12-18 | 1992-12-18 | Position transducer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9226480A GB2273568A (en) | 1992-12-18 | 1992-12-18 | Position transducer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9226480D0 GB9226480D0 (en) | 1993-02-10 |
| GB2273568A true GB2273568A (en) | 1994-06-22 |
Family
ID=10726860
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9226480A Withdrawn GB2273568A (en) | 1992-12-18 | 1992-12-18 | Position transducer |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2273568A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2541259A1 (en) * | 2011-06-27 | 2013-01-02 | AmSafe, Inc. | Sensors for detecting rapid deceleration/acceleration events |
| US8818759B2 (en) | 2011-04-05 | 2014-08-26 | Amsafe, Inc. | Computer system for remote testing of inflatable personal restraint systems |
| US8914188B2 (en) | 2011-04-05 | 2014-12-16 | Amsafe, Inc. | Computer system and graphical user interface for testing of inflatable personal restraint systems |
| US9156558B2 (en) | 2011-04-05 | 2015-10-13 | Amsafe, Inc. | Inflatable personal restraint systems |
| US9176202B2 (en) | 2011-04-05 | 2015-11-03 | Amsafe, Inc. | Electronic module assembly for inflatable personal restraint systems and associated methods |
| US10391960B2 (en) | 2017-02-28 | 2019-08-27 | Amsafe, Inc. | Electronic module assembly for controlling aircraft restraint systems |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1157179A (en) * | 1967-06-19 | 1969-07-02 | Gl Upravlenie Energetiki I Ele | Transducer Device for Measuring Relative Motion of Objects |
| GB1496976A (en) * | 1974-10-29 | 1978-01-05 | Illinois Tool Works | Positional transducers utilizing magnetic means |
| GB2019582A (en) * | 1978-04-21 | 1979-10-31 | Illinois Tool Works | Positional transducer utilizing magnetic elements |
| GB1571751A (en) * | 1977-02-02 | 1980-07-16 | Illinois Tool Works | Angular position sensors |
| US4646011A (en) * | 1983-12-17 | 1987-02-24 | Vdo Adolf Schindling Ag | Electronic angular position transmitter with toroidal core and rotatable magnet |
| US4774465A (en) * | 1986-03-27 | 1988-09-27 | Vacuumschmelze Gmbh | Position sensor for generating a voltage changing proportionally to the position of a magnet |
-
1992
- 1992-12-18 GB GB9226480A patent/GB2273568A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1157179A (en) * | 1967-06-19 | 1969-07-02 | Gl Upravlenie Energetiki I Ele | Transducer Device for Measuring Relative Motion of Objects |
| GB1496976A (en) * | 1974-10-29 | 1978-01-05 | Illinois Tool Works | Positional transducers utilizing magnetic means |
| GB1571751A (en) * | 1977-02-02 | 1980-07-16 | Illinois Tool Works | Angular position sensors |
| GB2019582A (en) * | 1978-04-21 | 1979-10-31 | Illinois Tool Works | Positional transducer utilizing magnetic elements |
| US4646011A (en) * | 1983-12-17 | 1987-02-24 | Vdo Adolf Schindling Ag | Electronic angular position transmitter with toroidal core and rotatable magnet |
| US4774465A (en) * | 1986-03-27 | 1988-09-27 | Vacuumschmelze Gmbh | Position sensor for generating a voltage changing proportionally to the position of a magnet |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8818759B2 (en) | 2011-04-05 | 2014-08-26 | Amsafe, Inc. | Computer system for remote testing of inflatable personal restraint systems |
| US8914188B2 (en) | 2011-04-05 | 2014-12-16 | Amsafe, Inc. | Computer system and graphical user interface for testing of inflatable personal restraint systems |
| US9153080B2 (en) | 2011-04-05 | 2015-10-06 | Amsafe, Inc. | Computer system for remote testing of inflatable personal restraint systems |
| US9156558B2 (en) | 2011-04-05 | 2015-10-13 | Amsafe, Inc. | Inflatable personal restraint systems |
| US9176202B2 (en) | 2011-04-05 | 2015-11-03 | Amsafe, Inc. | Electronic module assembly for inflatable personal restraint systems and associated methods |
| US10364034B2 (en) | 2011-04-05 | 2019-07-30 | Amsafe, Inc. | Circuitry for testing inflatable personal restraint systems |
| US11628937B2 (en) | 2011-04-05 | 2023-04-18 | Amsafe, Inc. | Inflatable personal restraint systems |
| EP2541259A1 (en) * | 2011-06-27 | 2013-01-02 | AmSafe, Inc. | Sensors for detecting rapid deceleration/acceleration events |
| CN102853853A (en) * | 2011-06-27 | 2013-01-02 | Am-安全公司 | Sensors for detecting rapid deceleration/acceleration events |
| US10391960B2 (en) | 2017-02-28 | 2019-08-27 | Amsafe, Inc. | Electronic module assembly for controlling aircraft restraint systems |
| US11021123B2 (en) | 2017-02-28 | 2021-06-01 | Amsafe, Inc. | Electronic module assembly for controlling aircraft restraint systems |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9226480D0 (en) | 1993-02-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |