An engine accessory with a wrap spring clutch, which is configured for selectively transmitting rotary power between a drive member and a shaft, and an actuator that is configured to selectively control the clutch. The actuator has first and second rotary flux elements, a clutch control ring and an electromagnet. The first rotary flux element is rotatably coupled to the drive member and has a plurality of first teeth that are spaced circumferentially about the rotary axis. The clutch control ring is rotatable about the rotary axis and is coupled to the tang of the wrap spring. The second rotary flux element is rotatably coupled to the clutch control ring. The second rotary flux element has a plurality of second teeth that are spaced circumferentially about the rotary axis. The electromagnet is selectively operable to generate a magnetic field that is transmitted between the first and second teeth.

A clutch/brake assembly includes: an input shaft arranged to be rotated, in use, by a motor; an output shaft configured to be rotated by the input shaft when brought into engagement therewith; rotating clutch plate elements configured to transmit torque from the input shaft to the output shaft when engaged; a logarithmic spring mounted around the input shaft; a translating shaft around the spring; an output sleeve between the output shaft and the clutch plate elements; and a solenoid connected to the translating shaft. The solenoid can be in at least two states and either cause movement of the translating shaft to compress the spring in first or second directions control the assembly.

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.

A thermal disconnect assembly for an integrated drive generator includes an input shaft, an output shaft, a eutectic solder, and a disconnect clutch. The input shaft is driven by an external mechanical source. The output shaft is coupled to the input shaft through a disconnect clutch in a coupled state, is driven by the input shaft and rotates with the input shaft in the coupled state. The eutectic solder is configured to hold the output shaft in the coupled state and melt upon reaching a threshold temperature. The disconnect clutch is configured to urge the output shaft toward a decoupled state upon melting of the eutectic solder such that the output shaft does not rotate with the input shaft in the decoupled state.

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.

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.