The present invention relates to an electromagnetic clutch and a compressor comprising the same.
An electromagnetic clutch is widely used in various devices such as compressor. A conventional electromagnetic clutch comprises a driving rotator driven to rotate, an armature facing the driving rotator in an axial direction, a driven rotator supporting the armature movably in the axial direction, and a coil for generating electromagnetic force when charged with electricity. By controlling the electricity to the coil, the armature is brought in and out of contact with the driving rotator, thus accomplishing the intermittent transmission of the rotating force. For instance, when the coil is charged with electricity, the armature is pressed against the driving rotator by an electromagnetic force, transmitting by friction the rotating force of the driving rotator to the driven rotator via the armature. When the coil is not charged with electricity, the armature is away from the driving rotator, and the rotating force of the driving rotator is not transmitted to the driven rotator.
The conventional electromagnetic clutch has a problem of heat generation. That is, the coil generates heat while it is charged with electricity. Further, bearings which rotatably support respective driving and driven rotators also generate heat.
However, the conventional electromagnetic clutches have not been provided with almost any provisions for radiating such heat. In other words, they were simply left to effect a self-cooling. Accordingly, there was a possibility of short-circuits caused by a temperature rise at the coil.