Abstract: A keyless rotation transfer unit may include a spline forming a pulley coupling force between an inner circumference of a shaft hole of a pulley and an outer circumference of a keyless shaft end forming one end of a shaft, with the keyless shaft end inserted into the shaft hole, and a flange nut screw-fastened to the keyless shaft end coming out of the shaft hole and forming a screw fastening force to press one surface of the pulley. In particular, the screw fastening force forms a shaft fastening force that causes a bearing to pressurize the other surface of the pulley, the bearing is coupled to the keyless shaft end and located at the rear of the pulley, and the flange nut forms a pulley holding force using the screw fastening force and the shaft fastening force.

Abstract: A keyless rotation transfer unit may include a spline forming a pulley coupling force between an inner circumference of a shaft hole of a pulley and an outer circumference of a keyless shaft end forming one end of a shaft, with the keyless shaft end inserted into the shaft hole, and a flange nut screw-fastened to the keyless shaft end coming out of the shaft hole and forming a screw fastening force to press one surface of the pulley. In particular, the screw fastening force forms a shaft fastening force that causes a bearing to pressurize the other surface of the pulley, the bearing is coupled to the keyless shaft end and located at the rear of the pulley, and the flange nut forms a pulley holding force using the screw fastening force and the shaft fastening force.

Abstract: An optical disk drive includes a case, a tray which is slidably provided to the case and receives an optical disk, and a ground member which is electrically connected to the case and contacts one side of the optical disk as the tray slides in or out of the case. In the optical disk drive, by removing a static electricity remaining on the optical disk through the ground member, where the tray is loaded, foreign materials such as dust can be prevented from adhering to the optical disk. Accordingly, a stable and accurate optical signal processing can be guaranteed, thereby improving the reliability of the optical disk drive and the optical disk.

Abstract: An optical disk drive includes a case, a tray which is slidably provided to the case and receives an optical disk, and a ground member which is electrically connected to the case and contacts one side of the optical disk as the tray slides in or out of the case. In the optical disk drive, by removing a static electricity remaining on the optical disk through the ground member, where the tray is loaded, foreign materials such as dust can be prevented from adhering to the optical disk. Accordingly, a stable and accurate optical signal processing can be guaranteed, thereby improving the reliability of the optical disk drive and the optical disk.