| 摘要 |
PURPOSE:To effectively fix a magnet protecting member to the bottom of an iron cup by absorbing an irregularity of sizes of parts by the deformation of a swelled portion of a cylindrical portion of the member. CONSTITUTION:An irregularity of sizes of parts is absorbed by radially outward deformation of a swelled portion 5h of a cylindrical portion 5a of a magnet protecting member 5. Since the size of the outer diameter of the cylindrical portion 5a of the member 5 at its bottom side is reduced by the size of the inner diameter of an array of magnets 4, the stationary portion 5b of the member 5 is less deformed, displacement of a through hole provided at the portion 5b for inserting a pin, and improper calking of a pin 1g due to tension and deformation of the pin inserting hole due to the deformation of the swelled portion 5h of the member 5 to the outer peripheral position can be entirely eliminated. Since the corner of the magnet 4 at the inner peripheral side is chambered at 4a along an edge line, it can prevent a stress from being applied to the corner of the magnet 4. Thus the member 5 is rigidly fixed to an iron cup 1.
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