Patent ID: 8714330

Claim:
An electromagnetic clutch apparatus, comprising: a rotational shaft rotatable to implement either one of an input and an output of a rotational driving force; a rotor integrally rotated with the rotational shaft about an axis and provided with a plurality of magnetic poles each having a first polarity and a second polarity being different from the first polarity, the first and second polarities of the magnetic poles being arranged alternately along a circumferential direction of the rotor; an armature supported to be rotatable relative to the rotor; a rotational member rotated to implement the other of the input and the output of the rotational driving force relative to the armature; an exciting coil stored in the rotor and generating magnetic flux so that the rotor electromagnetically attracts the armature; a housing possessing a first housing portion and a second housing portion, the first housing portion accommodating the rotational member, the rotor, the armature and the rotational shaft; and a magnetic flux detecting element arranged to face the magnetic poles along a direction of the axis so as to detect magnetic flux of the magnetic poles, the magnetic flux detecting element being mounted on a clutch control substrate which extends into the first housing portion along a radial direction of the rotational shaft so that one portion of the clutch control substrate on which is mounted the magnetic flux detecting element is positioned inside the first housing portion and an other portion of the clutch control substrate is positioned outside the first housing portion.