Position sensor for generating a voltage changing proportionally to the position of a magnet
First Claim
1. A magnetic position sensor for generating a signal corresponding to the position of a moveable test object, said test object generating a magnetic field, said sensor being for use with an alternating voltage source and comprising in combination with said test object:
- a strip-shaped core consisting of material having low magnetic coercivity disposed out of contact with said test object but within the magnetic field of said test object so as to be saturated thereby at a location along said core corresponding to the position of said test object;
two excitation coils spaced from each other with at least a portion of said core therebetween, said excitation coils respectively connectable to said alternating current source for oppositely magnetizing said core; and
a secondary coil wound around said core between said excitation coils, said secondary coil having terminals across which a position signal is measured,whereby upon magnetization of said core by said excitation coils, a simulated air gap is generated at a location along said core by said test object, thereby changing the voltage across said terminals of said secondary coil corresponding to said position signal.
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Accused Products
Abstract
A sensor for identifying the position of a test object has a strip-shaped core of low magnetic coercivity which is magnetized with opposite polarities by two excitation coils disposed at opposite ends of the core, and a secondary coil wrapped around the core between the two excitation coils. The test object generates a magnetic field which saturates the core at a location corresponding to the position of the test object between the two excitation coils, thereby simulating an air gap in the core at this location. The voltage across the terminals of the secondary coil changes in accordance with the position of the simulated air gap, thus providing a signal indicating the position of the test object.
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Citations
12 Claims
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1. A magnetic position sensor for generating a signal corresponding to the position of a moveable test object, said test object generating a magnetic field, said sensor being for use with an alternating voltage source and comprising in combination with said test object:
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a strip-shaped core consisting of material having low magnetic coercivity disposed out of contact with said test object but within the magnetic field of said test object so as to be saturated thereby at a location along said core corresponding to the position of said test object; two excitation coils spaced from each other with at least a portion of said core therebetween, said excitation coils respectively connectable to said alternating current source for oppositely magnetizing said core; and a secondary coil wound around said core between said excitation coils, said secondary coil having terminals across which a position signal is measured, whereby upon magnetization of said core by said excitation coils, a simulated air gap is generated at a location along said core by said test object, thereby changing the voltage across said terminals of said secondary coil corresponding to said position signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A magnetic position sensor for use with an alternating current source comprising:
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a strip-shaped core of low magnetic coercivity material; two excitation coils spaced from each other along said core, said coils connectable to said alternating current source for respectively generating oppositely directed magnetic flux in said core; at least one permanent magnet disposed a distance from said core between said excitation coils and generating a magnetic field which saturates said core at a location corresponding to the position of said magnetic between said excitation coils; and a secondary coil wound around said core between said excitation coils and having terminals across which a voltage is present when said excitation coils are connected to said alternating current source, said voltage varying in accordance with a change in the position of said magnet along said core between said excitation coils.
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Specification