| 摘要 |
A magnetic encoder 1 including a support member 2 attached to a rotating body 12 and a magnet member 3 fixed to the support member 2, the support member 2 and the magnet 4 are not attached to each other using an adhesive but the support member 2 and the plastic magnet 4 are joined together by molding shrinkage or wrap-around form of the magnet 4, and the material for the magnet 4 is selected such that the value of the ratio ((±p-±m)/µc) of a difference (±p - ±m) between flowing-direction linear expansion coefficient (±p) of the magnet 4 and linear expansion coefficient (±m) of the support member 2, to tensile breaking strain (µc) of the material for the magnet 4 is equal to or less than a value beginning at a threshold (Nth) based on a prescribed value of cycle number at thermal shock destructive test. |
