Patent ID: 6430144
Filing Date: 2002-08-06
Classification: F16F,G11B,Y10T

Abstract:
A control method for an auto-balancing system of an optical disk drive, said optical disk drive provided with a spindle motor and said spindle motor having an axis of rotation, said control method comprising the steps of:(a) providing the optical disk drive with the housing affixed to the spindle motor so as to rotate about the axis of rotation of the spindle motor; (b) forming in said housing at least one circular track, said at least one circular track coaxially located on the rotational axis of the spindle motor; (c) providing each of said at least one circular track with at least one balancing mass, wherein each of said at least one balancing mass is sized to move smoothly within said each of said at least one circular track; (d) driving the spindle motor into rotation such that an angular velocity about the rotational axis of the spindle motor increases linearly with time until said angular velocity is equal to a predetermined angular velocity, said predetermined angular velocity reinforcing a maximal imbalance of the auto-balancing system; (e) controlling said angular velocity about the rotational axis of the spindle motor to be equal to said predetermined angular velocity and maintaining said angular velocity at said predetermined angular velocity for a predetermined period of time; (f) further driving the spindle motor into rotation such that an angular velocity about the rotational axis of the spindle motor increases above said predetermined angular velocity predetermined constant acceleration, said predetermined constant acceleration being set so as to effectuate a maximal torque about the rotational axis of the spindle motor, wherein said maximal torque produces a relative displacement between said each of said at least one circular tracks and said each of said at least one balancing masses; and (g) terminating said predetermined constant acceleration when said angular velocity about said rotational axis of said spindle motor is equal to a maximum rotational speed of the spindle motor, wherein said maximum rotational speed is greater than a critical speed, wherein said critical speed is an angular velocity about the rotational axis of the spindle motor at which said each of said balancing masses smoothly moves to a location of mass within said housing which produces a maximal balance of said auto-balancing system.