Abstract: An armature is configured to come into contact with an actuator due to magnetic attraction force. An outer plate is fixed to an armature, the outer plate being located on an opposite side of the armature from the actuator, the outer plate being configured to rotate together with the armature. An inner hub is located between the armature and the outer plate to be movable in a direction along a rotation axis, the inner hub being fixed to a driven device. A rubber member is disposed between the inner hub and the outer plate to give an urging force to the inner hub and the outer plate in a direction away from each other. This electromagnetic clutch is configured such that the urging force of the rubber member non-linearly increases as the actuator and the armature approach each other due to the magnetic attraction force.

Abstract: An armature is configured to come into contact with an actuator due to magnetic attraction force. An outer plate is fixed to an armature, the outer plate being located on an opposite side of the armature from the actuator, the outer plate being configured to rotate together with the armature. An inner hub is located between the armature and the outer plate to be movable in a direction along a rotation axis, the inner hub being fixed to a driven device. A rubber member is disposed between the inner hub and the outer plate to give an urging force to the inner hub and the outer plate in a direction away from each other. This electromagnetic clutch is configured such that the urging force of the rubber member non-linearly increases as the actuator and the armature approach each other due to the magnetic attraction force.

Abstract: A power transmission device includes an electromagnet, a rotor, an armature and a hub that couples the armature to a shaft of a driving target device. The hub includes an outer hub coupled to the armature, an inner hub coupled to the shaft, and an elastic member interposed between the outer hub and the inner hub. An outer peripheral side of the inner hub includes plural extending parts each extending outward in a radial direction. An inner peripheral side of the outer hub includes an inner peripheral side wall that overlaps with the extending parts in a rotational direction and surrounds the extending parts. The elastic member is disposed in an unbonded state with respect to at least one of the inner hub and the outer hub between the outer peripheral side of the inner hub and the inner peripheral side of the outer hub.

Abstract: A power transmission device includes an electromagnet, a rotor, an armature and a hub that couples the armature to a shaft of a driving target device. The hub includes an outer hub coupled to the armature, an inner hub coupled to the shaft, and an elastic member interposed between the outer hub and the inner hub. An outer peripheral side of the inner hub includes plural extending parts each extending outward in a radial direction. An inner peripheral side of the outer hub includes an inner peripheral side wall that overlaps with the extending parts in a rotational direction and surrounds the extending parts. The elastic member is disposed in an unbonded state with respect to at least one of the inner hub and the outer hub between the outer peripheral side of the inner hub and the inner peripheral side of the outer hub.

Abstract: A plate (13(e)), the outer diameter side of which is fixed to be integral with a plate section (13c), and which is provided with an engagement part (13g) to be engaged with a shoulder (13f) formed on the inner diameter side of a boss section (13a), is integral with a center hub (13). Thereby, even if a bridge section (13d) is broken and the plate section (3c) moves in the detachment direction of the center hub (13), the engagement part (13g) of the plate (13e) is engaged with the shoulder (13f) of the boss section (13a), whereby the plate section (13c) and the boss section (13a) are engaged and coupled with each other while interrupting the torque transmission. Accordingly, even if the bridge section (13d) is broken, the boss section (13a) as well as the plate section (13c) side are prevented from being detached from a pulley (10).

Abstract: When a first damper contacts both of a protruding portion of a pulley body and a protruding portion of a center hub, a second damper is disposed as being apart from the protruding portion of the center hub with a gap. Even when the pulley body is rotated in a reverse direction, no reverse torque is thereby transmitted to the center hub as long as the gap exists, or before the second damper contacts the protruding portion of the center hub. As a result, torque fluctuation is sufficiently absorbed. This prevents the following: a reverse torque is transmitted to the center hub; a torque limiter wrongly acts; a fastening part between a shaft and the center hub loosens; or abnormal noise or aversive vibration takes place.

Abstract: A power transmission device which interrupts torque transmission when the torque exceeds a predetermined torque. A torque limiter includes projections formed on a center hub and a pulley. The center hub includes bridges that transmit torque by a pulling force. When a preset torque limit is reached, the projections on the center hub make contact with and move along slanted faces so as to move the center hub in an axial direction relative to the pulley. The bridges are thereby subjected to a bending moment in addition to the pulling force when the torque exceeds the preset torque level, so that the bridges break precisely above the preset torque level due to the reduced fatigue limit.

Abstract: A power transmission device includes a driving-side rotating body and a driven-side rotating body. The driving-side rotating body rotates via a drive source and has a concave fitting portion. The driven-side rotating body is connected to a rotary shaft and has a convex fitting portion. The convex fitting portion engages the concave fitting portion to transmit rotation of the driving-side rotating body to the driven-side rotating body. The driven-side rotating body includes an annular outer hub formed of resin and an annular inner hub formed of metal. The outer hub is in an outer circumferential part of the driven-side rotating body and has the convex fitting portion. The inner hub is in an inner circumferential part of the driven-side rotating body. The inner hub is insert molded into the outer hub. An outer diameter of the inner hub is larger than an inner diameter of the convex fitting portion.

Abstract: In a torque transmission system, plural engagement pieces elastically deformable are formed integrally with an outer peripheral portion of a circular portion of a center hub to be engaged with an inner periphery portion of a pulley. A bridge portion of the center hub is disposed to be broken when a torque large than a predetermined torque is applied there to. Since the engagement protrusion pieces are engaged with a part of the pulley, it can prevent the center hub from being removed and falling when the bridge portion of the center hub is broken.

Abstract: A hole is formed in a damper rubber, where by when a compressive load is small, pillar portions undergo a flexural deformation so as to result in buckling deformation. On the other hand, when the compressive load becomes large, the hole collapses and the damper rubber undergoes a compressive deformation so as to collapse itself. Thus, since the damper rubber has a non-linear characteristic such that an elastic modulus thereof at an amount of deformation exceeding a predetermined amount is larger than that at an amount of deformation less than the predetermined amount, the transmission of a large torque can be implemented while absorbing a torque fluctuation sufficiently.

Abstract: A plate 13e, the outer diameter side of which is fixed to be integral with a plate section 13c, and which is provided with an engagement part 13g to be engaged with a shoulder 13f formed on the inner diameter side of a boss section 13a, is integral with a center hub 13. Thereby, even if a bridge section 13d is broken and the plate section 13c moves in the detachment direction of the center hub 13, the engagement part 13g of the plate 13e is engaged with the shoulder 13f of the boss section 13a, whereby the plate section 13c and the boss section 13a are engaged and coupled with each other while interrupting the torque transmission. Accordingly, even if the bridge section 13d is broken, the boss section 13a as well as the plate section 13c side are prevented from being detached from a pulley 10.

Abstract: When a first damper contacts both of a protruding portion of a pulley body and a protruding portion of a center hub, a second damper is disposed as being apart from the protruding portion of the center hub with a gap. Even when the pulley body is rotated in a reverse direction, no reverse torque is thereby transmitted to the center hub as long as the gap exists, or before the second damper contacts the protruding portion of the center hub. As a result, torque fluctuation is sufficiently absorbed. This prevents the following: a reverse torque is transmitted to the center hub; a torque limiter wrongly acts; a fastening part between a shaft and the center hub loosens; or abnormal noise or aversive vibration takes place.

Abstract: A power transmission device which interrupts torque transmission when the torque exceeds a predetermined torque. A torque limiter includes projections formed on a center hub and a pulley. The center hub includes bridges that transmit torque by a pulling force. When a preset torque limit is reached, the projections on the center hub make contact with and move along slanted faces so as to move the center hub in an axial direction relative to the pulley. The bridges are thereby subjected to a bending moment in addition to the pulling force when the torque exceeds the preset torque level, so that the bridges break precisely above the preset torque level due to the reduced fatigue limit.

Abstract: In a torque transmission system, plural engagement pieces elastically deformable are formed integrally with an outer peripheral portion of a circular portion of a center hub to be engaged with an inner periphery portion of a pulley. A bridge portion of the center hub is disposed to be broken when a torque large than a predetermined torque is applied there to. Since the engagement protrusion pieces are engaged with a part of the pulley, it can prevent the center hub from being removed and falling when the bridge portion of the center hub is broken.

Abstract: A hole is formed in a damper rubber, where by when a compressive load is small, pillar portions undergo a flexural deformation so as to result in buckling deformation. On the other hand, when the compressive load becomes large, the hole collapses and the damper rubber under goes a compressive deformation so as to collapse itself. Thus, since the damper rubber has a non-linear characteristic such that an elastic modulus thereof at an amount of deformation exceeding a predetermined amount is larger than that at an amount of deformation less than the predetermined amount, the transmission of a large torque can be implemented while absorbing a torque fluctuation sufficiently.