Abstract: A driven accessory (10) is provided that includes a first rotary clutch portion (50), a second rotary clutch portion (52), a wrap spring (56) and an actuator (60). The wrap spring (56) is configured to transmit rotary power between the first and second rotary clutch portions (50, 52). The actuator (60) is selectively operable for generating a drag force that is applied to the wrap spring (56) to control torque transmission through the wrap spring (56). The actuator (60) includes an actuator input member (140), a brake shoe (144) and a motor (142) that is configured to translate the brake shoe (144) axially along the rotary axis (70). The drag force is generated when the motor (142) is operated in a first mode so that transmission of rotary power between the first rotary clutch portion (50) and the second rotary clutch portion (52) is interrupted.

Abstract: In an aspect, a method is provided for controlling a clutch assembly having first and second rotatable clutch members. The method includes providing a wrap spring clutch having first and second ends. The phase angle between the first and second ends determines a diameter of the wrap spring clutch. One of the clutch members is connected with the first end. The method further includes obtaining a target value indicative of a target speed for the second clutch member, and determining through measurement an actual value that is indicative of an actual speed of the second clutch member. The method further includes changing the phase angle between the first and second ends of the wrap spring clutch to generate a selected amount of slip between the wrap spring clutch and the other of the first and second clutch members, based on the target value and the actual value.

Abstract: In an aspect, the invention is directed to a clutched device (such as, for example, a decoupler) that includes a clutch input member, a clutch output member, a wrap spring clutch. The wrap spring clutch has an overrun locking member thereon that is engageable with an overrun locking aperture in the output member so as to maintain a face at the helical end of the wrap spring clutch in engagement with a output member clutch drive face on the clutch output member.

Abstract: A decoupler that includes a drive member, a hub and an isolator that is configured to transmit rotary power between the drive member and the hub in a predetermined rotational direction. The isolator includes a wrap spring, a plurality of helical coil springs, and a carrier assembly. The wrap spring includes a plurality of helical coils and a proximal end. The helical coil springs are disposed between the hub and the carrier assembly. The carrier assembly includes a carrier plate and a spring shell. The carrier plate has a plate member with a rim and a spring groove. The rim abuts an axial end of the wrap spring. The proximal end of the wrap spring is received in the spring groove. The spring shell is assembled to the carrier plate and has a toric inner surface into which the helical coil springs are received.

Abstract: A decoupler assembly that includes a hub, a pulley and a mechanism for transmitting rotary power between the hub and the pulley. The mechanism includes a torsion spring and a one-way clutch. The torsion spring is configured to dampen vibration in the rotary power that is transmitted from the pulley to the hub. The one-way clutch has a wrap spring that is smaller in diameter than the torsion spring.

Abstract: In an aspect, a decoupler is provided, and included a driver having a clutch surface a hub that is disposed within the driver, and at least one torsionally-compliant member and a wrap spring clutch that are disposed in series between the hub and the clutch surface. The driver comprises a pulley and a cover that is received into a cavity in the pulley. The pulley has a belt-engagement surface and is fixedly coupled to the cover for rotation therewith. The cover defines the clutch surface.

Abstract: A tensioner having a closing-type torsion spring that is employed to bias a pivot arm about a pivot shaft. The tensioner includes a damper, which contacts an inside surface of the torsion spring to dampen torsional vibration transmitted through the torsion spring, and a one-way clutch that is configured to permit unencumbered rotation of the pivot shaft in one rotational direction but to resist rotation of the pivot shaft in an opposite direction.

Abstract: In a first aspect, the invention is directed to a multi-speed drive for controlling the speed of a load that is driven from a crankshaft of an engine. The multi-speed drive permits the speed of the load to be adjusted based on one or more parameters, such as vehicle speed, engine RPM, battery charge level (e.g. when the load is an alternator), coolant temperature (e.g. when the load is a cooling fan), engine power demand from the vehicle driver, water level in which the vehicle is driving (e.g. when the load is a cooling fan whose blades could be damaged or could cause damage to other vehicle components if they impact water during use). The speeds provided by the multi-speed drive may include two or more non-zero rotational speeds, or two or more non-zero rotational speeds and a zero speed, or one non-zero rotational speed and a zero speed.

Abstract: In an aspect the invention is directed to an isolator comprising a shaft connector that is connectable with a shaft of a motive device, a first rotary drive member that is operatively engageable with at least one second rotary drive member, a first isolation spring and a second isolation spring. The first rotary drive member and the shaft connector are rotatable about an isolator axis. The motive device may be an engine (and thus the shaft may be a crankshaft), or a motor for assisting an engine, for example. Examples of motors for assisting engines include motor/generator units (MGU's) that can operate as a generator when driven to rotate mechanically, and can operate as a motor when driven to rotate electrically. The first isolation spring is positioned to transfer a torque from the first rotary drive member to the shaft connector. The second isolation spring is positioned to transfer a torque from the shaft connector to the first rotary drive member.

Abstract: In one aspect, the invention relates to a tensioner that is capable of precognitively anticipating when it is desirable to increase the tension in a belt or other endless drive element so as to prevent belt slip prior to events that would raise the risk of it.

Abstract: In an aspect, a tensioner for an endless drive member, comprising a shaft and base that are mountable to be stationary relative to an engine, a tensioner arm that is pivotable relative to the shaft about a tensioner arm axis, a pulley on the tensioner arm rotatable about a pulley axis that is offset from the tensioner arm axis, and that is engageable with an endless drive member, a tensioner spring that is positioned to urge the tensioner arm towards a free arm position, a damping element that engages the tensioner arm and that is engaged by a plurality of axially spaced segments of the tensioner spring.

Abstract: In an aspect, a decoupler includes a hub, a pulley, a torsion spring, a first spring driver fixed to the pulley, and having a first stop feature for the spring; a second spring driver mounted about the hub and not fixed to the pulley, and having a second stop feature for the spring, a driving clutch shaft mounted connected to the second spring driver, a driven clutch shaft mounted concentrically with the driving clutch shaft and drivingly connected to the hub, a one-way wrap spring clutch mounted about the hub and disposed to interconnect the driving and driven clutch shafts, and configured to transfer torque in a first direction between the driving and driven clutch shafts, and an axial biasing member acting between one of (i) the pulley and the driving clutch shaft and (ii) the hub and driven clutch shaft, to urge the driving and driven clutch shafts together.

Abstract: In an aspect the invention is directed to an isolator comprising a driver that is connectable with a shaft of a device, a rotary drive member that is engageable with an endless drive member; and a first isolation spring and a second isolation spring. The first and second isolation springs are positioned such that during rotation of the driver in a first direction torque is transferred from the driver to the first rotary drive member through the first isolation spring and not through the second isolation spring, and such that during rotation of the first rotary drive member in the first direction torque is transferred from the first rotary drive member to the driver through the second isolation spring and not through the first isolation spring.

Abstract: In a first aspect, a tensioner is provided which includes: an arm, including a pivot mount; a pulley rotatably mounted to the arm; and a strut pivotally connected to the arm. The strut includes: a base, having a pivot mount; a first body moveable relative to the base; a first resilient element connected between the base and the first body, the first resilient element having a first stiffness coefficient; a second body moveable relative to the first body, the second body having a pivot mount; a second resilient element connected between the first body and the second body, the second resilient element having a second stiffness coefficient that is lower than the first stiffness coefficient; and an actuator, connected to the base and first body, for selectively moving the first body towards the base and compressing the first resilient element.

Abstract: A tensioner (24) for tensioning an endless drive member (14) on an accessory drive system or a cam shaft drive system is provided with a vent structure (99) that opens into a cavity (68) of the tensioner (24) to permit reduction of any pressure in the cavity (68) and the ambient environment of the tensioner (24), while inhibiting ingress of contaminants into the cavity (68). In some embodiments the vent structure (99) includes one or more of a mechanical one-way valve (152), a semi-permeable membrane (311) or a passageway with a circuitous path.

Abstract: A method of setting an air gap between an electromagnetic coil and an armature of an electro-mechanical device to be within a desired range includes applying a sensing signal to the electromagnetic coil and monitoring at least one electrical characteristic of the electromagnetic coil. The at least one electrical characteristic is related to a size of the air gap and the sensing signal. The method further includes moving the armature towards the electromagnetic coil to reduce the size of the air gap and stopping movement of the armature towards the electromagnetic coil when the at least one electrical characteristic indicates the size of the air gap is within the desired range.

Abstract: An engine starter apparatus having a clutch assembly and a ring gear or pulley. The clutch assembly has a plate structure, a drive hub and a clutch element for selectively coupling the drive hub to the plate structure. The ring gear or pulley is coupled to the plate structure.

Abstract: A clutched driven device (10) having a clutch assembly (16) with a first rotary clutch portion (50), a second rotary clutch portion (52), a bearing (54), a wrap spring (56) and an actuator (60). The first rotary clutch portion has an interior clutch surface (76). The first and second rotary clutch portions are rotatably disposed about a rotary axis (70) of the clutched driven device. The bearing is received between the first and second rotary clutch portions and supports the first rotary clutch portion for rotation on the second rotary clutch portion. The wrap spring is disposed radially inwardly of the bearing and has a plurality of helical coils (114) that are received against the interior clutch surface. The actuator is configured to selectively initiate coiling of the wrap spring to cause the helical coils of the wrap spring to disengage the interior clutch surface to a predetermined extent.