Light balance shaft assembly with simply supported beam structure

The invention provides a light balance shaft assembly with a simply supported beam structure. The balance shaft assembly comprises a balance shaft support with a center hole and a balance shaft; the improvement is that: an extension part is formed outside the balance shaft support and is fixedly connected with an end cover; the inner side of the end cover is provided with a shaft groove opposite to the center hole; one end of the balance shaft is arranged in the center hole and the other end of the balance shaft is arranged in the shaft groove; the end cover is fixedly connected with the end face of the balance shaft; and the inner wall of the center hole and the inner wall of the shaft groove restrain two ends of the balance shaft so as to form the simply supported beam structure. The balance shaft assembly has the advantages that: the stress condition of the balance shaft can be improved obviously; and the manufactured balance shaft is thinner and smaller than the conventional balance shaft under the condit