Fiber optic sensor system for detecting movement or position of a rotating wheel bearing
First Claim
1. A fiber optic sensor system for detecting movement or position of a rotating wheel bearing in a bearing assembly, said system comprising:
- a source of light;
a magneto-optical material for modulating said light, said magneto-optical material having discrete magnetic domains each domain having an anisotropic optical property;
means for detecting an intensity of said modulating light;
means for carrying said light between said source of light, said magneto-optical material and said means for detecting;
a multi-pole magnetic tone ring for creating a varying magnetic field in the vicinity of said magneto-optical material indicative of movement and position of said rotating wheel bearing wherein said magnetic field causes said domains to align themselves to said magnetic field thus causing the optical property of said domains to become continuous when viewed from a single direction, wherein the amount of alignment of said domains is proportional to the speed of said rotating wheel bearing and the amount of light transmitted is a function of the amount of alignment of said domains.
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Accused Products
Abstract
An improved fiber optic sensor system and integrated sensor bearing assembly for detecting movement or position of a rotating wheel bearing having a multi-pole tone ring which produces an alternating magnetic field indicative of movement and position of the rotating member. A magneto-optical material, such as a bismuth garnet iron (B.I.G.) crystal, having discrete magnetic domains is positioned in the vicinity of the tone ring so that the domains align themselves to the magnetic field generated by the tone ring. A single fiber optic cable, preferably single mode fiber, carries light generated by a source of light to the B.I.G. crystal. The light passes through the B.I.G. crystal and is refracted at domain boundaries in the crystal. The intensity of the refracted light is indicative of the amount of alignment of the domains and therefore the strength of the magnetic field. The refracted light is carried by the fiber optic cable to an optic receiver where the intensity is measured and an electrical signal is generated and sent to a controller indicating the frequency of the changes in light intensity and therefore the rotational speed of the rotating wheel bearing.
25 Citations
21 Claims
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1. A fiber optic sensor system for detecting movement or position of a rotating wheel bearing in a bearing assembly, said system comprising:
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a source of light; a magneto-optical material for modulating said light, said magneto-optical material having discrete magnetic domains each domain having an anisotropic optical property; means for detecting an intensity of said modulating light; means for carrying said light between said source of light, said magneto-optical material and said means for detecting; a multi-pole magnetic tone ring for creating a varying magnetic field in the vicinity of said magneto-optical material indicative of movement and position of said rotating wheel bearing wherein said magnetic field causes said domains to align themselves to said magnetic field thus causing the optical property of said domains to become continuous when viewed from a single direction, wherein the amount of alignment of said domains is proportional to the speed of said rotating wheel bearing and the amount of light transmitted is a function of the amount of alignment of said domains. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An integrated fiber optic sensor bearing assembly for detecting the movement or position of a rotating wheel bearing comprising:
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a stationary ring; an rotating ring configured to rotate with said wheel bearing and around said stationary ring; a tone ring operably connected to said rotating ring, said tone ring having multiple poles and being configured to rotate with said rotating ring producing an varying magnetic field indicative of said wheel bearing rotational speed and position; a magneto-optical material for modulating light generated by an external source of light, said magneto-optical material having discrete magnetic domains each domain having an anisotropic optical property wherein said magnetic field causes said domains to align themselves to said magnetic field thus causing the optical property of said domains to become continuous when viewed from a single direction, wherein the frequency of alignment of said domains is proportional to the rotational speed of said wheel bearing; a reflective surface operably connected to said magneto-optical material for reflecting said modulated light wherein the amount of light reflected is proportional to the amount of alignment of said domains; a fiber optic cable for carrying said light between said source of light and said magneto-optic material and for carrying said reflected light to an external means for detecting light. - View Dependent Claims (17, 18, 19, 20, 21)
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Specification