An electromagnetic clutch includes an armature to be attracted to a rotor, an armature hub formed on one end portion of a rotating shaft, and a leaf spring which connects the armature to the armature hub and biases the armature away from the rotor. The leaf spring includes a base fixed to the armature hub, a stopper connected to the base, and a connecting piece surrounding the stopper by projecting outside from the base, and fixed to the armature. A through hole into which a rivet for fixing the base to the armature hub is inserted is formed in the base. A low-strength portion having strength lower than that in the periphery of the through hole is formed in a boundary portion between the base and a connecting portion.

Provided is an electromagnetic clutch, in which a plurality of magnetic flux shielding slits extending in the axial direction and arcuately in the circumferential direction are formed individually in a rotor and an armature, and in which the magnetic flux by the excitation of a coil inserted on the anti-armature side of the rotor is passed from the non-slit portion of the rotor to the non-slit portion of the armature and from the non-slit portion of the armature to the non-slit portion of the rotor, so that a magnetic attraction is generated to bring two frictional faces into press contact with each other and so that the two frictional faces are separated by the demagnetization of the coil. The slits of at least one of the rotor and the armature are formed to change in such a taper shape that the slit width at the frictional face side may be smaller than that at the anti-frictional face side. Without inviting any drastic cost increase, the mutual press-contact force of the frictional faces can be enhanced so that a higher torque transmission may be possible with the same size as that of the conventional structure.

An electromagnetic clutch includes a coil (57) generating a first magnetic flux or a second magnetic flux depending on the direction of current flowing therein, a stationary core (55) accommodating therein the coil, a stationary magnet (59) providing a magnetic flux that opposes the first magnetic flux, a rotor rotatable concentrically with a rotatable shaft, a moving core fixed to the rotor, a moving magnet (71) providing a magnetic flux that opposes the second magnetic flux, a sun gear (73) fixed to the rotatable shaft, an internal gear (75) fixed to the rotor, a planetary gear (77) meshed with the sun gear and the internal gear, an arm (63) supporting the planetary gear, a pulley rotatable concentrically with the rotatable shaft, a first armature (81) being capable of coupling to the stationary core, and a second armature (83) being capable of coupling to the moving core.

Apparatus for transmitting movement to a driven part (510;510,1) idle on a bearing (2d), comprising a shaft (2) on which the driven part (510;510,1) is mounted; movement generating means (11) connected to the shaft (2), an electromagnetic clutch (400) which comprises a rotor (410) axially fixed to and rotationally integral with the shaft (2), a fixed electromagnet (422), and an armature (432) situated axially opposite the electromagnet (422) on the opposite side to the rotor (410), in which said armature (432) has a set of radial inner teeth (432a) able to engage with a corresponding set of teeth (4a) of a bush (4) integral with the shaft (2) together with which it rotates, between the armature (432) and the rotor (410) there being axially arranged resilient means (433) able to keep the armature (432) pushed towards the driven part (510;510,1) and therefore engaged with the teeth (4a) of the bush (4), the armature (432) carries a member (515) able to engage with the driven part (510;510,1), energization/de-energization of the electromagnet (422) causing an idle/rotating condition of the driven part (510;510,1).

Es wird eine elektromagnetisch betätigbare Reibscheibenkupplung mit einem Elektromagneten sowie einem Rotor und einem Ankerelement vorgeschlagen, die mittels des Elektromagneten mit einem Magnetfeld für ein Zusammenwirken von Rotor und Ankerelement beaufschlagbar sind, wobei das Ankerelement an Rückstellmittel (50) angeordnet ist, durch die das Ankerelement entlang einer Rotationsachse des Rotors über Magnetkräfte um einen Verschiebeweg in eine Anlageposition am Rotor bewegbar ist und ohne Magnetkräfte elastisch in eine Position zurückkehrt, in welcher das Ankerelement und der Rotor sich berührungsfrei gegeneinander bewegen können. Erfindungsgemäß umfassen die Rückstellmittel (50) neben einen elastischen Anteil (51) einen plastischen Anteil (52), der bei einem vergrößerten originären Verschiebeweg durch Verschleiß zu einer plastischen Verformung der Rückstellmittel (50) führt, so dass die Vergrößerung des Verschiebewegs zumindest teilweise kompensierbar ist.

A clutch pulley (10) for selectively engaging a belt of a first device and a shaft (14) of a second device, including a sheave member (20), an electro-magnetic coil (22), a flex plate (24), and a ring member (26). The sheave member includes a sheave belt surface (28) adapted to engage the belt and a sheave clutch surface (30). The electro-magnetic coil is adapted to selectively create an electro-magnetic flux. The flex plate includes a flex inner section (34) concentrically coupled over the shaft, a flex outer section (36) adapted to selectively move between two axial positions relative to the flex inner section based upon the presence of the electro-magnetic flux, and a flex spoke section (38) connecting the flex inner section and the flex outer section. The ring member is connected to the flex outer section and includes a ring clutch surface (40) adapted to selectively engage the sheave clutch surface based upon the axial position of the flex outer section.

A electromagnetic clutch (1) comprises a hub (10) rigidly fitted on a drive shaft (2) and having a flange portion (11), a rotor (20) which is rotatable about the drive shaft (2), a magnetic coil (21) arranged in the rotor (20), an armature plate (30) which is magnetically attracted into abutment with the rotor (20) upon energisation of the magnetic coil (21), and a plurality of spring members (40) interposed between the hub flange portion (11) and the armature plate (30) along a circumference of the rotor (20), for connection between the flange portion (11) and the armature plate (30). The armature plate (30) comprises a first annular disc (30a axially opposed to the rotor (20) with a predetermined axial gap therebetween, a second annular disc (30b) connected to the first annular disc (30a) in a manner axially opposed thereto with a predetermined space (30x) formed therebetween, and at least one elastic body (30c) held in the predetermined space (30x) between the first annular disc (30a) and the second annular disc (30b).

An electromagnetic clutch (1) which is capable of reducing a variation in torque (reaction force) from a refrigerant compressor. The electromagnetic clutch (1) includes a hub (10) rigidly fitted on a drive shaft (2) and having a flange portion (11), a rotor (20) which is rotatable about the drive shaft( 2), a magnetic coil (21) arranged within the rotor (20), an armature plate (30) which is attracted into abutment with the rotor (20) when the magnetic coil (21) is energized, and a plurality of spring members (40) interposed between the flange portion (11) of the hub (10) and the armature plate (30) along a circumference of the rotor (20), for connection between the flange portion (11) of the hub (10) and the armature plate (30). The armature plate (30) comprises a rotor-side annular disc (30a, 30b) axially opposed to the rotor (20) with a predetermined axial gap therebetween, a spring-side annular disc (30d) arranged on a spring member side of the rotor-side disc (30a, 30b) in a manner axially opposed thereto, and an elastic body (30c) interposed between the rotor-side annular disc (30a, 30b) and the spring-side annular disc (30d) in a manner such that the elastic body (30c) is joined to the rotor-side annular disc (30a, 30b) and the spring-side annular disc (30d).

In a clutch (10) actuated by an electromagnet (20) associated with a first magnetic rotatable member (15) to attract an armature plate (26) mounted with limited axial movement on the flange (242) of a hub (24) force-fitted on a shaft (13), female-threaded extractor holes (242a) are sealed, e.g. by a plate (40) fixed to the flange (242) by rivets (290), to eliminate drops of water entering the clutch via the holes (242a) to corrode the bearings (16). A tool (300) is disclosed (Fig 3 - not shown) for removing the hub (24) from the shaft (13) by screwing into the holes (242a).

An electromagnetic clutch (10) has a clutch rotor (15) with two concentric parts (150, 151) separated radially by an elastic annulus (155) e.g. of compressed rubber.

0 An electromagnetically controlled spring clutch mechanism comprises an input rotary element (20), a rotor (22) an armature (24), a biasing spring member (50) for biasing the armature in a direction away from the rotor, an electromagnetic means (28) for magnetically attracting the armature to the rotor against the biasing action of the biasing spring member, and a coil spring means (100). The clutch mechanism is adapted to transmit the driving force of the input rotary element by the contraction of the coil spring means. The biasing spring member (50) is fixed to a supporting member (52) by a plate-like spring fixing member (86) to form a sub-assembly. The clutch mechanism can be used in either of two arrangements by changing the assembling sequence of various constituent elements. Projections (94) which contact or approach the rotor beyond the armature are provided in the supporting member - (52) to which one end of the coil spring means is connected. Also disclosed is a contruction of the electromagnetic means, which can be applied not only to the electromagnetically controlled spring clutch mechanism but also to other types of electromagnetic clutch mechanisms.