Hall Effect position sensor with flux limiter and magnetic dispersion means

A position sensor for sensing position of a metallic tone wheel, said sensor having a loaded state which occurs when said sensor senses a metallic object and an unloaded state which occurs when said sensor senses a void, said sensor comprising:

• a Hall effect device which produces an output signal in response to magnetic flux-levels in excess of a predetermined limit;
• magnetic means for producing a first level of magnetic flux in excess of said predetermined limit;
• means for conducting magnetic flux produced by said magnetic means to said Hall effect device, said conducting means including means for limiting magnetic flux and means for dispersing magnetic flux;
• said dispersing means including a surface across which magnetic flux is dispersed, said surface including a slot sized to receive said Hall effect device therein below said surface, said Hall effect device being attached in said slot;
• wherein said limiting means, is situated adjacent said magnetic means and, receives said first level of magnetic flux from said magnetic means and supplies a reduced second level of magnetic flux to said dispersing means, and said dispersing means disperses said second level of magnetic flux below said predetermined limit at said Hall effect device when said sensor is in an unloaded state, said Hall effect device producing an output signal when said sensor is in its loaded state in response to magnetic flux levels in excess of said predetermined limit.

A position sensor, comprising:

• a Hall effect device;
• a hollow cylindrical magnet having a first base and a second base, said magnet producing axial magnetic flux;
• a first annular ring-shaped pole piece attached to said first base;
• a second annular ring-shaped pole piece attached to said second base;
• flux return means for magnetically shunting a portion of the flux from said first ring-shaped pole piece to said second ring-shaped pole piece, said flux return means inserted through said first pole piece and disposed within the hollow portion of said magnet;
• and
• wherein said Hall effect device is attached to said second pole piece over the center of said second pole piece and produces an output signal in response to magnetic flux levels at said Hall effect device in excess of a predetermined limit.