Magnetic drum and magnetic encoder with the same

Abstract

A magnetic drum and a magnetic encoder including same. The magnetic drum comprises a permanent magnet magnetic ring body (); the permanent magnet magnetic ring body () comprises an inner ring wall () and an outer ring wall (); the inner ring wall () has a single first polarity, the outer ring wall () has a single second polarity, and the first polarity is opposite to the second polarity; the inner ring wall () and the outer ring wall () are coaxially arranged; one of the inner ring wall () and the outer ring wall () is uniformly provided with a plurality of protrusions () around the axis of the permanent magnet magnetic ring body (), and a recess () is formed between any two adjacent protrusions ().