Automatic tensioning wheel for engine belt

The invention discloses an automatic tensioning wheel for an engine belt. The structural design of an existing tensioning wheel results in the problems that a tensioning wheel is difficult to position in machining and large in accuracy error and affects actual working condition backlash of a bearing and generates abnormal sound when working. According to the automatic tensioning wheel for the engine belt, an inner ring of a bearing is provided with an eccentric wheel capable of rotating around a pivot, the inner ring of the bearing is fixedly provided with a shifting fork, the periphery of the pivot is sleeved with a torsion spring, the torsion spring transmits elasticity between a base and the shifting fork through the two ends of the torsion spring, and the elasticity of the torsion spring drives the inner ring of the bearing to rotate around the pivot towards the direction of a tensioning belt through the shifting fork, so tensioning is achieved. According to the automatic tensioning wheel for the engine belt, the inner ring of the bearing is provided with the eccentric hole through the inner diameter, the inner ring of the bearing is fixedly provided with the shifting fork, and the elasticity of the torsion spring drives the inner ring of the bearing to rotate around the pivot towards the direction of the tensioning belt through the shifting fork to achieve tensioning. Due to the fact that an original shifting fork piece is omitted, the number of machining surfaces and machining difficulty are reduced, and the risk that the size of backlash is difficult to control and the risk of sidewiping of the belt due to close fitting of the inner ring of the bearing are avoided.