| 摘要 |
PURPOSE:To facilitate insertion of a spindle to the spindle insertion hole of an information recording medium by chamfering the end part of an internal wall on the entrance side of the spindle insertion hole of a magnetism sensing hub. CONSTITUTION:The information recording medium is constituted with an information recording disk 10 and the sensing magnetic hub 20 and has a construction where the sensing magnetic hub 20 is installed in a transmission hole part in the center of the information recording disk 10. The sensing magnetic hub 20 has the construction where a magnetism sensing piece 24 is installed in the magnetism sensing hub main body 21 and has the spindle insertion hole 25 in the center of it and a chamfering part 22 is provided in the end part of the internal wall on the entrance side of the spindle insertion hole. The magnetism sensing hub 20 includes a projection which is inserted into the inside of the transmission hole 13 of the information recording disk 10 and the chamfering part 23 is provided in the upper end part of the periphery of the projection. Thus, the fixing operation to the spindle and the detaching operation from the spindle in the driving part of a player can be facilitated. |
