GB2279148A - Magnetic position transducer - Google Patents
Magnetic position transducer Download PDFInfo
- Publication number
- GB2279148A GB2279148A GB9312518A GB9312518A GB2279148A GB 2279148 A GB2279148 A GB 2279148A GB 9312518 A GB9312518 A GB 9312518A GB 9312518 A GB9312518 A GB 9312518A GB 2279148 A GB2279148 A GB 2279148A
- Authority
- GB
- United Kingdom
- Prior art keywords
- core
- position transducer
- transducer according
- transducer
- coil
- 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- Withdrawn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
- G01D5/204—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 mutual induction between two or more coils
- G01D5/2066—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 mutual induction between two or more coils by movement of a single coil with respect to a single other coil
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/003—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring position, not involving coordinate determination
-
- 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
- G01D2205/00—Indexing scheme relating to details of means for transferring or converting the output of a sensing member
- G01D2205/70—Position sensors comprising a moving target with particular shapes, e.g. of soft magnetic targets
- G01D2205/77—Specific profiles
- G01D2205/775—Tapered profiles
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
A position-sensing transducer comprises a magnetically permeable core 10 of varying cross-section and two coils 12, 14 disposed around the core, one coil 12 being fixed and other coil 14 being slidable relative to the core. The transducer may be a rotary position transducer comprising a circular or tubular core 10 which tapers around at least part of its circumference. Alternatively, the transducer may be a linear position transducer having a linear core forming an open magnetic circuit. Preferably the core 10 comprises a ferromagnetic amorphous alloy in the form of a wound ribbon. <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.
There is a need for an electrical transducer of simple construction and low cost, for use in a variety of applications in automobiles. We have now devised such a transducer.
In accordance with this invention, there is provided a position transducer which comprises a core of magnetically permeable material and varying cross-section, a coil disposed around the core at a fixed position thereof, and a coil disposed around the core and slidable relative to the core.
The magnetic coupling, which is provided between the two coils by the common core, varies according to the position of the movable coil, because of the varying cross-section of the core. Therefore if a constant current is fed through one coil, the voltage across the other coil will vary according to the position of the movable coil. In addition to the coupling via the core, there may be some mutual coupling between the two coils, which increases as the coils approach each other: the core may be shaped to take account of this so that the transducer provides an output voltage linearly related to the position of the movable coil.
Preferably the transducer is a rotary position transducer comprising a circular, annular or tubular core, forming a closed magnetic circuit, the core tapering around at least part of its circumference.
The transducer may instead comprise a linear position transducer, comprising a linear core forming an open magnetic circuit.
The core may comprise any ferromagnetic material. A preferred material is ferromagnetic amorphous alloy in the form of a ribbon, which is therefore easy to form to the required shape. Typical such alloys follow the atomic composition formula TXMlsx 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-formed elements 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.
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 magnetically permeable core 10 in the form of a tube. This core may be made by wrapping a ribbon of ferromagnetic amorphous alloy into tubular shape. The core shown tapers in the axial dimension over at least a portion of its circumference.
A coil 12 is disposed around the core 10 at a fixed position, and a coil 14 is disposed around the core 10 but is able to slide circumferentially around the core. The coils 10,12 are preferably wound on bobbins, through which the ribbon forming the core is threaded before the ends of the ribbon are joined together. The bobbin of the movable coil 14 is mounted to an element which moves angularly relative to the axis of the tubular core: the rotary or angular position of this element is to be determined by the transducer.
In use, a constant current is fed through one of the coils, as primary, e.g. the fixed coil 12. The voltage developed across the other or secondary coil varies according to the position of the movable coil 14, because the coupling between the coils via the core varies with the cross-section of the core at the position of the movable coil. There may also be some mutual coupling between the two coils, which increases as the coils approach each other. Preferably the taper of the core takes account of any such mutual coupling, so that the output from the secondary coil varies linearly with angular position of the movable coil.
It will be seen that the transducer which has been described is of simple construction and involves a minimum of components and is therefore of low cost. Furthermore, the coils 12,14 are easy to wind onto bobbins and then thread onto the core before the ends of the latter are joined together: the transducer is therefore simple to make. However, the transducer is reliable and effective in performance.
Claims (14)
1) A position transducer, comprising a core of magnetically permeable material and varying cross-section, a coil disposed around the core at a fixed position thereof, and a coil disposed around the core and slidable relative to the core.
2) A position transducer according to claim 1, wherein said core is shaped such that said transducer provides an output voltage which is linearly related to the position of said slidable coil.
3) A position transducer according to claims 1 or 2 wherein said transducer is a rotary position transducer.
4) A position transducer according to claims 1, 2 or 3 wherein said core forms a closed magnetic circuit.
5) A position transducer according to claim 4, wherein said core is circular.
6) A position transducer according to claim 4, wherein said core is annular.
7) A position transducer according to claim 4, wherein said core is tubular.
8) A position transducer according to any of claims 3 to 7, wherein said core tapers around at least part of its circumference.
9) A position transducer according to claims 1 or 2, wherein said transducer is a linear position transducer.
10) A position transducer according to claim 9, wherein said core is a linear core which forms an open magnetic circuit.
10) A position transducer according to any preceding claim, wherein said core comprises a ferromagnetic material.
11) A position transducer according to claim 10, wherein said ferromagnetic material is ferromagnetic amorphous alloy in the form of a ribbon.
12) A position transducer according to claim 11, wherein said ferromagnetic amorphous alloy follows the atomic composition formula TxMx, where T represents one or more of the transition elements iron (Fe), nickel (Ni) or cobalt (Co),
M represents one or more of the metalloid or glass-formed elements phosphorous (P), boron (B), carbon (C) or silicon (Si) and where X represents the transition metal content.
13) A position transducer according to claim 12, wherein X is in the range 75 to 86%.
14) A position transducer as hereinbefore described with reference to the accompanying drawing.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9312518A GB2279148A (en) | 1993-06-17 | 1993-06-17 | Magnetic position transducer |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9312518A GB2279148A (en) | 1993-06-17 | 1993-06-17 | Magnetic position transducer |
Publications (2)
Publication Number | Publication Date |
---|---|
GB9312518D0 GB9312518D0 (en) | 1993-08-04 |
GB2279148A true GB2279148A (en) | 1994-12-21 |
Family
ID=10737331
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9312518A Withdrawn GB2279148A (en) | 1993-06-17 | 1993-06-17 | Magnetic position transducer |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2279148A (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1502697A (en) * | 1975-03-18 | 1978-03-01 | Metrawatt Gmbh | Position transducer |
GB2131178A (en) * | 1982-11-30 | 1984-06-13 | Peutec Limited | Piston position transducer |
WO1991009277A2 (en) * | 1989-12-11 | 1991-06-27 | British Technology Group Ltd | Position sensor |
-
1993
- 1993-06-17 GB GB9312518A patent/GB2279148A/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1502697A (en) * | 1975-03-18 | 1978-03-01 | Metrawatt Gmbh | Position transducer |
GB2131178A (en) * | 1982-11-30 | 1984-06-13 | Peutec Limited | Piston position transducer |
WO1991009277A2 (en) * | 1989-12-11 | 1991-06-27 | British Technology Group Ltd | Position sensor |
Also Published As
Publication number | Publication date |
---|---|
GB9312518D0 (en) | 1993-08-04 |
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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) |