Patent ID: 6948464

Claim:
A protection device for an engine having a variable valve timing controller, comprising: an input member driven by a drive shaft of the engine; an output member connected with a cam shaft for opening and closing the valve; an electrical motor generating a rotational force; a phase converter driven by the electrical motor for converting the phase of the input member and output member; and a safety device for disconnecting a motor shaft of the electrical motor from the phase converter when a rotational load is applied to the motor shaft and the phase converter, the rotational load being above a predetermined value, wherein the safety device comprises an outer receptacle on the surface of the motor shaft, an inner receptacle at an inner periphery of a union mounted to the motor shaft, said inner receptacle confronting the outer receptacle, a ball engaging with the outer receptacle and the inner receptacle, and a spring biasing the ball towards the outer receptacle, and wherein when the rotational load of more than said predetermined value is applied to the motor shaft and the phase converter, the ball is disengaged from the outer receptacle so that the safety device disconnects the motor shaft from the phase converter.