Needle bearing limiting structure of thrust arm for pneumatic disc brake

The utility model discloses a needle roller bearing limiting structure of a thrust arm for an air pressure disc brake. The needle roller bearing limiting structure comprises a thrust arm assembly structure and a needle roller half-moon bearing. The thrust arm assembly structure is composed of a thrust arm, a blocking piece with a blocking step and a rivet, the blocking face of the blocking piece with the blocking step is provided with the blocking step, and the blocking piece with the blocking step is fixed to the thrust arm through the rivet in an interference fit mode. The roller pin half-moon bearing is composed of a plastic retainer, roller pins and a steel backing, the roller pins are placed in an inner cavity of the plastic retainer, the plastic retainer is used for fixing the multiple roller pins, the small components are placed in corresponding arcs of the steel backing after being formed, the small components are in sliding connection with the inner sides of the arcs of the steel backing, and the thr