Position sensor system with magnetically anisotropic flux guide

1. A position sensor system comprising:

a magnet;

a magnetic flux sensor positioned a distance away from said magnet, said magnetic flux sensor and said magnet defining a flux path therebetween; and

a flux guide positioned in said flux path to guide magnetic flux to said magnetic flux sensor, said flux guide being a layered structure having a plurality of ferro-magnetic layers formed from a ferro-magnetic material and a plurality of non-magnetic separating layers formed from a non-magnetic material, said non-magnetic separating layers of said plurality of non-magnetic separating layers being positioned between adjacent layers of said plurality of ferro-magnetic layers.

2. The system of claim 1 wherein said magnet is a permanent magnet.

3. The system of claim 1 wherein said magnet is mounted to a rotatable shaft.

4. The system of claim 3 further comprising a second magnet mounted to said rotatable shaft, said second magnet having an opposite polarity than said magnet.

5. The system of claim 1 wherein said magnetic flux sensor is a Hall effect sensor.

6. The system of claim 1 wherein said distance is at least about 2 millimeters.

7. The system of claim 1 wherein said ferro-magnetic material is steel.

8. The system of claim 1 wherein said non-magnetic material is air.

9. A position sensor system comprising:

a rotatable shaft;

a first magnet connected to said shaft;

a second magnet connected to said shaft, said second magnet having a opposite polarity than said first magnet;

a Hall effect sensor positioned a distance away from said first and second magnets; and

a flux guide positioned at least partially between said first and second magnets and said Hall effect sensor, said flux guide being a layered structure having a plurality of planar and parallel layers.

10. The system of claim 9 wherein said first and second magnets are permanent magnets.

11. The system of claim 9 wherein said distance is at least about 2 millimeters.

12. The system of claim 9 wherein said flux guide includes at least two layers of a ferro-magnetic material separated by a layer of non-magnetic material.

13. The system of claim 12 wherein said ferro-magnetic material is steel.

14. The system of claim 12 wherein said non-magnetic material is air.

15. The system of claim 9 wherein said flux guide includes at least three alternating layers of a ferro-magnetic material and a non-magnetic material.

16. A position sensor system comprising:

a shaft defining a rotation axis;

a plurality of magnets circumferentially connected to said shaft, each of said plurality of magnets having an opposite polarity than adjacent ones of said plurality of magnets;

at least one magnetic flux sensor positioned a distance away from said plurality of magnets, said magnetic flux sensor and said plurality of magnets defining a flux path therebetween; and

a flux guide positioned in said flux path, said flux guide being a layered structure having a plurality of ferro-magnetic layers formed from a ferro-magnetic material and a plurality of non-magnetic separating layers formed from a non-magnetic material, said non-magnetic separating layers of said plurality of non-magnetic separating layers being positioned between adjacent layers of said plurality of ferro-magnetic layers, wherein each of said plurality of ferro-magnetic layers and said plurality of non-magnetic separating layers are planar and parallel with respect to other layers of said plurality of ferro-magnetic layers and said plurality of non-magnetic separating layers.

17. The position sensor of claim 1 wherein each layer of said plurality of ferro-magnetic layers and each layer of said plurality of non-magnetic separating layers is formed as a planar strip.

18. The position sensor of claim 1 wherein said non-magnetic material is polystyrene foam.