The present invention relates to a pulley for an alternator, and in particular, to a pulley for an automotive alternator.
An alternator is a type of generator that can produce an alternating current by converting mechanical energy into electrical energy. An automotive alternator converts mechanical energy of an engine into electrical energy to charge a battery, so as to supply electrical power to other electrical appliances on the automobile, and start a motor to rotate the engine.
An alternator generally has an annular stator and a rotor received in the annular stator. A wire is wound on the stator, and the rotor rotates rapidly in the stator so that the wire moves relative to a magnetic field generated by the rotor, and an induced electromotive force (voltage) is generated in the wire.
An automotive alternator is usually utilized by an engine driving a belt. The belt is wound on a pulley, and the pulley is connected to a rotor so as to drive the rotor to rotate. However, in conventional alternator design, when an engine starts, or accelerates or decelerates quickly in an instant, a waveform changes significantly at the moment the generator charges a battery, and it cannot be stabilized. In addition, one side of the belt wound on the pulley is tight, and the other side thereof is slack. The tension of the slack-side belt is low, and therefore a tensioner is disposed thereon to adjust the tension of the belt. However, when a rotation speed at which the engine transmits power changes suddenly, because the pulley of the generator is locked by a nut and the belt is made of a flexible material and cannot reflect the rotation speed immediately, a slip is easily caused between the belt and the pulley. Moreover, the fluctuation of the rotation speed causes the belt to bear not only a repeated stress but also a centrifugal force that is applied on the belt when the pulley rotates. The value of the centrifugal force changes with the rotation speed, and therefore the belt is often affected by adverse factors of an internal micro tension, which pulls the belt, and external large-amplitude shaking.