A two-speed pulley assembly for an engine accessory drive includes a planetary gear, a pulley, a friction clutch, a one-way clutch, and a torsional isolator. The planetary gear has a ring gear, a sun gear, a planet carrier and at least one planet gear. The planet carrier is arranged for driving engagement with an engine crankshaft. The pulley circumscribes the ring gear and is in driving engagement with the ring gear. The friction clutch is arranged to selectively prevent rotation of the sun gear. The one-way clutch permits rotation of the sun gear relative to the ring gear in a first rotational direction, and prevents rotation of the sun gear relative to the ring gear in a second rotational direction, opposite the first rotational direction. The torsional isolator is drivingly connected to the planet carrier and arranged to rotate at a same speed as the planet carrier.

The present invention discloses an electromagnetic clutch of a brushless control-by-wire centrifugal ball arm engagement device, which comprises a brushless electromagnet, a thrust pressing disc, a driven inner-spline hub, a control-by-wire drive disc, a centrifugal ball arm hollow disc, centrifugal ball arm pins, centrifugal ball arms, centrifugal balls, a magnetic conductive force transmitting disk, a drive shaft; once the brushless electromagnet is energized, the centrifugal ball arms and the centrifugal balls each make a circular motion around the centrifugal ball arm pin outwardly along the smooth surface of the thrust pressing disc by the action of centrifugal force produced by them when rotating with high speed. The component of the centrifugal force in the direction of the central axis of the centrifugal ball arm hollow disc drives the thrust pressing disc to compress the outer-spline-groove steel sheets and the inner-spline-groove friction discs with each other, which makes the clutch engaged. The clutch is engaged smoothly with no impact, which is suitable for high-speed rotation and transmitting large torque.

The present invention discloses an electromagnetic clutch of a brushless control-by-wire centrifugal ball arm engagement device, which comprises a brushless electromagnet, a thrust pressing disc, a driven inner-spline hub, a control-by-wire drive disc, a centrifugal ball arm hollow disc, centrifugal ball arm pins, centrifugal ball arms, centrifugal balls, a magnetic conductive force transmitting disk, a drive shaft; once the brushless electromagnet is energized, the centrifugal ball arms and the centrifugal balls each make a circular motion around the centrifugal ball arm pin outwardly along the smooth surface of the thrust pressing disc by the action of centrifugal force produced by them when rotating with high speed. The component of the centrifugal force in the direction of the central axis of the centrifugal ball arm hollow disc drives the thrust pressing disc to compress the outer-spline-groove steel sheets and the inner-spline-groove friction discs with each other, which makes the clutch engaged. The clutch is engaged smoothly with no impact, which is suitable for high-speed rotation and transmitting large torque.

A clutch system includes a friction clutch, a ramp system, a pilot clutch, and an actuation element. The friction clutch is for transmitting torque between a torque-introducing element and a torque discharging element. The friction clutch includes a pressure plate. The system is for axially moving the pressure plate. The ramp system has an input ramp and an output ramp. The output ramp is rotatable relative to the input ramp to change an axial extent of the ramp system. The pilot clutch is for initiating rotation of the input ramp relative to the output ramp in response to a speed differential between the torque-introducing element and the torque-discharging element. The actuation element is arranged radially on the inside relative to the friction clutch and is at least partially covered by the friction clutch when viewed in a radial direction.

A clutch system includes a friction clutch, a ramp system, a pilot clutch, and an actuation element. The friction clutch is for transmitting torque between a torque-introducing element and a torque discharging element. The friction clutch includes a pressure plate. The system is for axially moving the pressure plate. The ramp system has an input ramp and an output ramp. The output ramp is rotatable relative to the input ramp to change an axial extent of the ramp system. The pilot clutch is for initiating rotation of the input ramp relative to the output ramp in response to a speed differential between the torque-introducing element and the torque-discharging element. The actuation element is arranged radially on the inside relative to the friction clutch and is at least partially covered by the friction clutch when viewed in a radial direction.

A rotation transmission device is configured such that when an electromagnet of an electromagnetic clutch is energized, an armature is attracted toward a rotor, so that a control retainer defining a two-way clutch is moved in an axial direction, whereby the control retainer and a rotary retainer are rotated relative to each other in a direction in which circumferential widths of pockets decrease, thereby disengaging pairs of rollers from an inner periphery of an outer ring and an outer periphery of an inner ring. The rotation transmission device includes a shock absorbing member on a surface of the armature facing the rotor, the shock absorbing member being configured to absorb impact force when the armature is attracted to the rotor by being elastically deformed.

A rotation transmission device is configured such that when an electromagnet of an electromagnetic clutch is energized, an armature is attracted toward a rotor, so that a control retainer defining a two-way clutch is moved in an axial direction, whereby the control retainer and a rotary retainer are rotated relative to each other in a direction in which circumferential widths of pockets decrease, thereby disengaging pairs of rollers from an inner periphery of an outer ring and an outer periphery of an inner ring. The rotation transmission device includes a shock absorbing member on a surface of the armature facing the rotor, the shock absorbing member being configured to absorb impact force when the armature is attracted to the rotor by being elastically deformed.

A rotating shaft device, comprising a fixed carter (21) and driving means integral to at least one of one or more rotating shafts (8) of the rotating shaft device, each driving means having its own integrated control and power supply unit (11, 25), allows the transmission of signals, even with low intensity, to this unit and to this regard it comprises: one or more annular antennas (24), connected to said respective control and power supply unit (11, 25) and arranged so as to at least partially surround one or more of said rotating shafts (8), and integral to the rotating shaft (8) of the respective control and power supply unit (11, 25), so that said rotating shafts (8) act as wave guide for the signals received from said one or more annular antennas (24) and intended to be received by the respective control and power supply unit (11, 25) to drive said driving means associated thereto; and radio transmission means (26), integral with the carter (21) and associated to one or more of said rotating shafts (8) to send signals therethrough to said one or more annular antennas (24).

A device is configured to control activation of a low-friction clutch, wherein the low-friction clutch includes a first member coaxial to a second member and a controllable activation device interposable therebetween. The device includes a piston that is mechanically coupled to the activation device, a spring that is disposed to urge the piston in a first direction, a controllable electrical coil disposed adjacent to the piston. The electrical coil is disposed to generate an electro-magnetic force to urge the piston in a second direction that is opposed to the first direction when activated, and the spring and the electrical coil interact with the piston to selectively mechanically couple the first and second members via the controllable activation device.

A device is configured to control activation of a low-friction clutch, wherein the low-friction clutch includes a first member coaxial to a second member and a controllable activation device interposable therebetween. The device includes a piston that is mechanically coupled to the activation device, a spring that is disposed to urge the piston in a first direction, a controllable electrical coil disposed adjacent to the piston. The electrical coil is disposed to generate an electro-magnetic force to urge the piston in a second direction that is opposed to the first direction when activated, and the spring and the electrical coil interact with the piston to selectively mechanically couple the first and second members via the controllable activation device.