System for concentrating magnetic flux of a multi-pole magnetic structure
An improved system for concentrating magnetic flux of a multi-pole magnetic structure at the surface of a ferromagnetic target uses pole pieces having a magnet-to-pole piece interface with a first area and a pole piece-to-target interface with a second area substantially smaller than the first area, where the target can be a ferromagnetic material or a complementary pole pieces. The multi-pole magnetic structure can be a coded magnetic structure or an alternating polarity structure comprising two polarity directions, or can be a hybrid structure comprising more than two polarity directions. A magnetic structure can be made up of discrete magnets or can be a printed magnetic structure.
1. A system for concentrating magnetic flux, comprising:
a multi-pole magnetic structure comprising one or more pieces of a magnetizable material having a plurality of polarity regions for providing a magnetic flux, said magnetizable material having a first saturation flux density, said plurality of polarity regions being magnetized in a plurality of magnetization directions; and
a plurality of pole pieces of a ferromagnetic material for integrating said magnetic flux across said plurality of polarity regions and directing said magnetic flux at right angles to at least one target, said ferromagnetic material having a second saturation flux density, each pole piece of said plurality of pole pieces having a magnet-to-pole piece interface with a corresponding polarity region and a pole piece-to-target interface with said at least one target, and having an amount of said ferromagnetic material sufficient to achieve said second saturation flux density at the pole piece-to-target interface when in a closed magnetic circuit, said magnet-to-pole piece interface having a first area, said pole piece-to-target interface having a second area, said magnetic flux being routed into said pole piece via said magnet-to-pole interface and out of said pole piece via said pole piece-to-target interface, said routing of said magnetic flux through said pole piece resulting in an amount of concentration of said magnetic flux at said pole piece-to-target interface corresponding to the ratio of the first area divided by the second area, said amount of concentration of said magnetic flux corresponding to a maximum force density.
2. The system of claim 1 , wherein said polarity regions are separate magnets.
3. The system of claim 1 , wherein said polarity regions have a substantially uniformly alternating polarity pattern.
4. The system of claim 1 , wherein said polarity regions have a polarity pattern in accordance with a code having a code length greater than 2.
5. The system of claim 4 , wherein said code is a Barker code.
6. The system of claim 1 , wherein said polarity regions are printed magnetic regions on a single piece of magnetizable material.
7. The system of claim 6 , wherein said printed magnetic regions are separated by non-magnetized regions.
8. The system of claim 6 , wherein said printed magnetic regions are stripes.
9. The system of claim 8 , wherein said stripes are groups of printed maxels.
10. The system of claim 1 , wherein said target is a ferromagnetic material.
11. The system of claim 1 , wherein said target is a complementary pole piece.
12. The system of claim 1 , further comprising:
a shunt plate for producing a magnetic flux circuit between at least two polarity regions of said plurality of polarity regions.
13. The system of claim 1 , wherein each of said plurality of polarity regions has one of a first magnetization direction or a second magnetization direction that is opposite to said first magnetization direction.
14. The system of claim 1 , wherein each of said plurality of polarity regions has one of a first magnetization direction, a second magnetization direction that is opposite to said first magnetization direction, a third magnetization direction that is perpendicular to said first magnetization direction, or a fourth magnetization direction that is opposite to said third magnetization direction.
15. The system of claim 1 , wherein a thickness of said one or more pieces of magnetizable material is sufficient to just provide said magnetic flux having said first flux density at said magnet-to-pole interface as required to achieve said maximum force density at said pole piece-to-target interface.
16. The system of claim 1 , wherein a length of at least one pole piece of said plurality of pole pieces is substantially equal to a length of at least one polarity region of said plurality of polarity regions.
17. The system of claim 1 , wherein a length of at least one pole piece of said plurality of pole pieces is less than a length of at least one polarity region of said plurality of polarity regions.
18. The system of claim 1 , wherein a length of at least one pole piece of said plurality of pole pieces is greater than a length of at least one polarity region of said plurality of polarity regions.
19. The system of claim 1 , wherein at least one pole piece of said plurality of pole pieces and said at least one target have a male-female type interface.
20. The system of claim 1 , wherein at least one pole piece of said plurality of pole pieces is tapered.