Decoupler with torque-limiting feature to protect components thereof

A decoupler, comprising:

• a decoupler input member;
• a decoupler output member, wherein the decoupler input member is rotatable relative to the decoupler output member, and wherein the decoupler input member and the decoupler output member are rotatable about an axis;
• a one-way clutch positioned to receive torque from the decoupler input member;
• and
• an isolation spring that is a helical torsion spring, having a first helical end and a second helical end, and having a first axial end and a second axial end, and having a radially outer surface and a radially inner surface, wherein the isolation spring is positioned to receive torque from the one-way clutch, and to transmit torque to the decoupler output member at least indirectly, through the second helical end, wherein the isolation spring changes size radially based on how much torque is being transferred through the isolation spring,
• wherein the decoupler input member includes a radial projection that is positioned to frictionally engage one of the radially outer and radially inner surfaces of the isolation spring when the isolation spring reaches a selected radial size, wherein, frictional engagement of the radial projection with the isolation spring generates torque transfer directly from the decoupler input member to the isolation spring in parallel with torque transfer from the decoupler input member to the isolation spring through the one-way clutch,
• wherein the decoupler input member is a pulley and the decoupler output member is a hub that is shaped to mount to a shaft of an accessory.