Patent ID: 6559637
Filing Date: 2003-05-06
Classification: G01D

Abstract:
A non-contact rotational position sensor comprising:a permanent magnet having a circular or arc-shaped outer circumference; a shaft for supporting and fixing said permanent magnet; upper and lower magnetic plates sandwiching said permanent magnet from above and below, at least one of said upper and lower magnetic plates being horizontally separated from each other with an air gap formed therebetween; at least one protruded magnetic substance portion disposed between said upper and lower magnetic plates; and a magnetic sensitive device disposed on a protruded surface of said protruded magnetic substance portion, said permanent magnet and said shaft constituting a rotor which is rotatable relative to said upper and lower magnetic plates vertically spaced from each other, said permanent magnetic being magnetized substantially in the direction of a rotating axis, whereby the amount of magnetic flux passing said magnetic sensitive device is varied with rotation of said permanent magnet, wherein said upper and lower magnetic plates sandwiching said permanent magnet from above and below are formed of magnetic plates each having protruded portions at opposite ends instead of providing said protruded magnetic substance portion on at least one of said upper and lower magnetic plates, said protruded portions being bent to form pairs of upper and lower protruded portions, and said magnetic sensitive device is inserted in an air gap formed between protruded surfaces of every two upper and lower protruded portions.