| 摘要 |
PURPOSE:To enhance the productivity of an upper side plate by constructing the upper side plate constituting a magnetic circuit by plural annular members fitting to each other coaxially. CONSTITUTION:The upper side plate 9 is constructed by fitting externally the annular member 8 having a larger diameter than that of an annular member to the annular member 7 constituting an upper side plate for a small magnet. In such a manner, by suitably combining one type annular member 7 having an internal diameter dimension which has the high accuracy with the annular member 8 requiring no dimension accuracy, the upper side plate 9 corresponding to magnets of various types of dimensions can be produced and the production efficiency can be remarkably enhanced. |
