ENCODER

摘要

An encoder (1), in which N-poles (5) and S-poles (6) of magnets are arranged alternately in a circumferential direction and in which an unequal pitch portion (8) is disposed on a portion of the circumference. The encoder (1) having the unequal pitch portion (8) can be easily manufactured without using a magnetizing head of a special shape having an unequal pitch portion. The unequal pitch portion (8) is formed by arranging the N-poles (5) and the S-poles (6) at an equal pitch all over the circumference and by providing a portion on the circumference with a shielding member (7) for shielding a magnetism. Furthermore, the unequal pitch portion (8) is formed by arranging the N-poles (5) and the S-poles (6) at an equal pitch all over the circumference and by providing a portion in the circumference with a removed portion.