Abstract: In an electromagnetic coupling apparatus, an excitation coil constituted by a plurality of turns of a winding member is covered with a resin coil bobbin. The coil bobbin can be divided into at least two members and is formed into a hollow annular shape. The divided mating surfaces of the members constituting the coil bobbin are joined to each other by ultrasonic welding.

Abstract: A terminal connection structure of an electromagnetic coupling device includes terminal housing unit, an extraction hole, a flat contact portion, a conductive mount member, and a conductive support member connected to a power source lead line. The terminal housing unit is formed integrally with a resin coil bobbin having an electromagnetic coil therein, and projects from a through hole formed in a yoke having an annular groove in which the resin coil bobbin is press-fitted. The extraction hole is formed in the terminal housing unit to extract one end of a winding of the electrogmagnetic coil. The flat contact portion is formed between a pair of grooves formed on two sides thereof in the terminal housing unit, and one end of the winding extracted from the extraction hole is brought into contact with the flat contact portion. The conductive mount member is press-fitted in one groove of the terminal housing unit to hold a portion of the winding brought into contact with the flat contact portion.

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.

Abstract: In a power transmission device, guide elements, which are to be secured to a mounting portion of a driver, are axially fitted through and circumferentially arranged on a brake element concentrically disposed around a hollow tubular shaft which is adapted to be fitted on an output rotary shaft of the driver for rotation therewith. The brake element is urged by springs engaging the respective guide elements, toward an operating element which axially moves the brake element. An input element concentrically secured on the hollow tubular shaft and a friction plate concentrically and rotatably disposed thereabout have first and second openings, respectively, which are axially alignable with the guide elements, whereby the guide elements and the springs can be mounted into and removed from the power transmission device, through the aligned first and second openings.

Abstract: In an electromagnetic spring-wound clutch, an input rotary member is concentrically and rotatably fitted on an output rotary member having an annular enlarged portion, with its axial boss disposed adjacent the above annular enlarged portion. A coil spring is wound around the axial boss and the annular enlarged portion for gripping engagement with at least the former, with its one end engaged by the output rotary member and its other end by a sleeve concentrically and rotatably supported on the input and output rotary members. An armature is disposed for axial tilting about its one edge supported by a stationary member. Responsive to extinction of electromagnetic force caused by deenergization of a magnetic coil, the armature is axially tilted by the force of a spring into engagement with the sleeve to hold same from rotating.

Abstract: An electromagnetic spring-wound clutch includes a first rotary member formed of a hub having an annular flange and a tubular portion integrally combined with the hub and adapted for direct coupling to a rotary shaft of an apparatus for use with the clutch. The tubular portion of the first rotary member is concentrically and rotatably fitted through a stationary annular field core which accommodates an electromagnetic coil and is arranged in facing relation with the annular flange of the hub. A non-magnetic annular member is rigidly fitted on the hub, and an armature is rotatably fitted on the hub and interposed between the annular flange and the annular member. A coil spring is wound around the annular member and a second rotary member rotatably fitted on the tubular portion of the first rotary member, for gripping engagement therewith.

Abstract: An axially displaceable brake element is arranged in facing relation to an operating element which is pivotable through a predetermined circumferential angle, with clutch balls engaged in grooves having slanted bottoms and formed in mutually facing side surfaces of the brake element and the operating element. Pivoting of the operating element causes displacement of the brake element relative to the operating element. A friction plate is spline-fitted on an output hub so as to be displaced only in the axial directions and arranged selectively for frictional contact with the brake element or the operating element. Displacement of the brake element toward the operating element causes frictional engagement of the friction plate with an input hub to obtain engagement of the clutch, while displacement of the brake element away from the operating element causes frictional engagement of the friction plate with the brake element to obtain disengagement of the clutch and braking of the output hub.