ELECTROMAGNETIC SPRING CLUTCH

PURPOSE:To allow a clutch to be disengaged when the titled device reaches above a certain temperature at the failure of compressor for thereby preventing an engine from the excessive imposition of load and a subsequential break-down, by constituting an armature of clutch for a car air conditioner compressor with a heat sensitive material. CONSTITUTION:Upon a shaft 3 ceasing to rotate at the breakdown of compressor, the load of shaft 3 is transmitted to a pulley 1. On the other hand, because an engine still outputs a power to cause a sliding friction at an area between a spring 7 and bosses 1c, 2b and moreover at an area between an armature 8 and the side face 1d of pulley, whereby producing a frictional heat in the vicinity of spring 7. As a result, the temperature of armature 8 rises to lower its magnetic characteristic so that the magnetic force of permanent magnet 9 can overcome. Therefore, the armature 8 moves away from the side face 1d to adhere to a flange portion 6c, whereas the diameter of spring 7 is returned to its original position to abut its outer diameter surface against the inner surface of shell 6b. In this manner, an operating safety can be ensured without the chance of load being transmitted to the side of pulley 1 or the engine at the time of breakdown.