ELECTROMAGNETIC CLUTCH AND DRIVING FORCE TRANSMISSION DEVICE USING THE CLUTCH

摘要

PROBLEM TO BE SOLVED: To suppress fluctuations of the clutch characteristics of an electromagnetic clutch and prevent the generation of noise by decreasing the fluctuation width of a repetition fluctuation of a carried current during duty control of an energizing current to the electromagnetic coil of an electromagnetic clutch. SOLUTION: A copper ring 18 which is a nonmagnetic and high conductive member is disposed in the vicinity of the circulation magnetic circuit X of an electromagnetic clutch. By disposing the copper ring 18, a counter electromotive voltage due to a fluctuation of the number of magnetic fluxes is generated and a reverse direction current in a direction reverse to the current fluctuation of an electromagnetic coil is generated. The reverse current is operated to offset a fluctuation of an energizing current, resulting in reduction of the fluctuation width of the repeat fluctuation of the carried current, maintenance of the engaging force of the electromagnetic clutch in a state reduced in a fluctuation width, and reduction of the generation of noise due to the repeating fluctuations of the engaging force.