Patent ID: 9271083
Filing Date: 2016-02-23
CPC Classification: H04R

Claim Text:
1. A speaker magnetic circuit comprising: a yoke including a disk-like base end portion and a columnar center pole protruding from a center portion of the base end portion; an annular magnet arranged on the base end portion; an annular top plate arranged on the magnet so that an inner circumferential surface thereof is opposite to an outer circumferential surface of the center pole, the annular top plate having a smaller inner circumferential diameter than an inner circumferential diameter of the annular magnet; and a non-magnetic ring member arranged on an inner circumferential surface of the magnet, the non-magnetic ring member having a same inner circumferential diameter as an inner circumferential diameter of the top plate, an upper end of the non-magnetic ring member, which is located on the annular top plate side, contacting a lower surface of the annular top plate, and a lower end of the non-magnetic ring member, which is located on the base end portion side, not contacting the base end portion.