| 摘要 |
PURPOSE:To minimize the off-track degree which is produced by the linear expansion between a magnetic disk and a magnetic disk, by setting an approximately equal linear expansion coefficient between the magnetic disk and a rack gear, and making the off-track degree per unit temperature change and track radius independent in relation with each other. CONSTITUTION:The material of a rack gear 6 is set properly so as to obtain an approximately equal linear expansion between the gear 6 and a magnetic disk 3. Thus it is possible to make the off-track degree per unit temperature change and the track radius independent in relation with each other. Thus an equal off-track degree is always secured even through the write and read of a magnetic head are carried out on any track. Thus the off-track degree can be easily asseured. Furthermore a proper material is selected for the linear expansion coefficient of a head arm 8, a carriage 7, a head assembly 9, a base 1 and the gear 6 respectively. Then the absolute value can be minimized for the variation of the off-track degree by setting the length of the materials of said parts at the proper value respectively. |
