A hinge assembly includes a body having a housing. A plug is disposed and locked inside said housing. A resilient sleeve is received in said plug. The resilient sleeve includes a first portion having two first peripheral surfaces and a second peripheral surface and a second portion disposed therebetween. The first portion is attached to the second portion at the two first peripheral surfaces and defines a frictional hole and two gaps therebetween. Each of the gaps allows the first portion to be stretchably bonded with the second portion. A pintle includes a pivoting portion being disposed in the frictional hole. The pivoting portion includes two curved surfaces and two flat surfaces formed thereon, wherein one of the flat surfaces is positioned correspondingly to the second peripheral surface, and one of the flat surfaces corresponds to the second portion.