Abstract: A decoupling pulley having a rim attached to a first power transmission element, and a torsion spring mounted in a receptacle attached to a second power transmission element, one of the power transmission elements being driving and the other of the power transmission elements being driven, the receptacle is a bell inside which is centered the spring, which spring has a first and a second end region, each of which bears on a bearing face of the bell, wherein the rim has a first drive abutment having a first face cooperating with the first end region of the spring to drive the latter in the direction of closure in a first relative rotational direction between the rim and the bell, the bell includes a first bell abutment, the angular position of which defines a first given maximum value ?1 for the travel of the first end region of the spring driven to close by the first drive abutment.

Abstract: The invention relates to an uncoupling pulley comprising a rim secured to a first power-transmitting element, and a torsion spring mounted in a receptacle secured to a second power-transmitting element, one of the power-transmitting elements being a driving element and the other of the power-transmitting elements being driven, characterized in that the receptacle is a bell-housing inside which the spring is centered, which spring has a first end region (12) and a second end region (14), each of which regions bears against a bearing face (32, 34) of the bell-housing (3), in that the rim has at least one first driving stop (42) having a first face (47) collaborating with the first end region (12) of the spring (1) to drive the latter in the direction of closing up in a first direction of relative rotation of rim (4) and bell-housing (3), and in that the bell-housing (3) comprises at least one first bell-housing stop (37, 37?, 118) of which the angular position defines a first given maximum value ai for the trav