Abstract: In a power transmission apparatus, a torque limiter mechanism has a plurality of holding portions, a disc plate and a flange, and an elastic member. The plurality of holding portions are fixed to either one of a pulley and a hub and aligned substantially equidistantly in a circumferential direction. The disc plate and flange are provided to either one of the pulley and the hub and oppose the holding portions. The elastic member is frictionally connected to the holding portions and the disc plate and flange, and is fixed to the remaining one of the pulley and the hub. The elastic member has connecting portions and an elastic support. The connecting portions are frictionally connected to the holding portions and the disc plate and flange, and correspond in number to the holding portions.

Abstract: The electromagnetic clutch (10) includes a rotor assembly (12), an armature assembly (14) and a field assembly (16). The field assembly (16) includes a ring and flange assembly (86). A terminal passage (104) is provided through the base portion (100) of the circular ring 96 with a U-shaped cross-section that form as a toroidal chamber (98). An electromagnetic coil (90) is encased in a bobbin (88) and a cap (92) and inserted into the toroidal chamber with a bobbin terminal post (110) extending into the terminal passage (104). A terminal housing (120) with a terminal sleeve (142) telescopically receives the bobbin terminal post (110) and the terminal sleeve (142) extends into the terminal passage (104). Leads (112 and 114) from the electromagnetic coil (90) extend into the terminal housing (120). Terminals (122) are housed in terminal apertures (136 and 138) in the terminal housing ( 120) and are in contact with the leads (112 and 114).

Abstract: An electromagnetic coupling device is configured so that divided armatures disposed opposite to an electromagnetic flux producing member are magnetically attracted in a stepwise manner. When applied to an electromagnetic clutch, the coupling device comprises an output pulley serving as the magnetic flux producing member provided with a yoke in which an excitation coil is incorporated, an input pulley disposed coaxially with the output pulley and adapted to be coupled therewith when the excitation coil is energized, and a plurality of annular armatures adapted to be fastened to the input pulley and having diameters different from each other.