ELECTROMAGNETIC CLUTCH AND METHOD FOR MANUFACTURING SAME

摘要

A coil housing has an inner ring, which is shaped into an annular form and is placed on an inner side of an electromagnetic coil in a radial direction of a rotational axis. A thermal fuse is placed on an inner side of a coil inner peripheral end of the electromagnetic coil in the radial direction, so that the thermal fuse can be placed in such a manner that the thermal fuse does not limit a length of the electromagnetic coil in a direction of the rotational axis by using a radial thickness of the inner ring that is indispensable as a part of a structure of a magnetic circuit. Thus, it is possible to sufficiently limit occurrence of limiting of a size of the electromagnetic coil that is caused by the placement of the thermal fuse.

主权项

1. An electromagnetic clutch comprising:
a driving-side rotatable member that is made of a magnetic material and is rotated about a rotational axis upon receiving a rotational force from a rotational drive source; a driven-side rotatable member that is rotated about the rotational axis upon receiving the rotational force from the driving-side rotatable member; an electromagnetic coil that is shaped into an annular form, which is centered on the rotational axis, wherein the electromagnetic coil generates an electromagnetic attractive force upon energization of the electromagnetic coil; a coil housing that is fixed to a non-rotatable member and is made of a magnetic material, wherein the electromagnetic coil is received in and is fixed to the coil housing; an armature that is made of a magnetic material, wherein the armature is attracted to and attached to a friction surface of the driving-side rotatable member in an axial direction of the rotational axis by the electromagnetic attractive force generated from the electromagnetic coil; an elastic connector that joins between the driven-side rotatable member and the armature and is placed to rotate integrally with the driven-side rotatable member and the armature, wherein the elastic connector holds the armature at a location, which is spaced from the friction surface of the driving-side rotatable member, when the electromagnetic coil is not energized; and a thermal fuse that is fixed to the coil housing and is placed to receive frictional heat, which is generated by friction between the armature and the friction surface of the driving-side rotatable member, wherein the thermal fuse is melted and is opened to cut supply of an electric power to the electromagnetic coil when a temperature is equal to or higher than a predetermined temperature, and wherein the thermal fuse is placed on an inner side of an innermost part of the electromagnetic coil in a radial direction of the rotational axis.