A rotating shaft, comprising: a central shaft (10, 10a); a first bracket (20, 20a), rotatably mounted on the central shaft; a second bracket (30, 30a), fixedly connected to the central shaft; an elastic member (60, 60a, 60b, 60c), disposed on the central shaft; and a concave cam assembly (50, 50a), disposed on the central shaft, wherein the concave cam assembly is configured to enable the elastic member to be deformed; and wherein when the first bracket rotates relative to the second bracket, the concave cam assembly generates an extrusion force acting on the elastic member, so that the elastic member in a hollowed-out shape is deformed, and then a specific included angle is formed between the first bracket and the second bracket; wherein the central shaft comprises a fastening part, a blocking part, and a rod part that are fixedly connected, and the blocking part is located between the rod part and the fastening part; and the second bracket is fastened to the fastening part, the rod part sequentially passes through the first bracket, the concave cam assembly, and the elastic member, and the first bracket is held against the blocking part, wherein the rotating shaft further comprises a fastener, and the fastener is fastened to a side of the rod part facing away from the blocking part, and is held against a surface of the elastic member facing away from the concave cam assembly; characterised in that the elastic member is a hollow cylinder of an integrated structure, and a plurality of hollowed-out holes (63, 63a, 63b, 63c) and a plurality of connecting ribs (65, 65a, 65b, 65c) are disposed on a cylinder wall of the elastic member, and the plurality of hollowed-out holes are interleaved with the plurality of connecting ribs and are disposed at intervals to form the elastic member. a central shaft (10, 10a); a first bracket (20, 20a), rotatably mounted on the central shaft; a second bracket (30, 30a), fixedly connected to the central shaft; an elastic member (60, 60a, 60b, 60c), disposed on the central shaft; and a concave cam assembly (50, 50a), disposed on the central shaft, wherein the concave cam assembly is configured to enable the elastic member to be deformed; and wherein when the first bracket rotates relative to the second bracket, the concave cam assembly generates an extrusion force acting on the elastic member, so that the elastic member in a hollowed-out shape is deformed, and then a specific included angle is formed between the first bracket and the second bracket; wherein the central shaft comprises a fastening part, a blocking part, and a rod part that are fixedly connected, and the blocking part is located between the rod part and the fastening part; and the second bracket is fastened to the fastening part, the rod part sequentially passes through the first bracket, the concave cam assembly, and the elastic member, and the first bracket is held against the blocking part, wherein the rotating shaft further comprises a fastener, and the fastener is fastened to a side of the rod part facing away from the blocking part, and is held against a surface of the elastic member facing away from the concave cam assembly; characterised in that the elastic member is a hollow cylinder of an integrated structure, and a plurality of hollowed-out holes (63, 63a, 63b, 63c) and a plurality of connecting ribs (65, 65a, 65b, 65c) are disposed on a cylinder wall of the elastic member, and the plurality of hollowed-out holes are interleaved with the plurality of connecting ribs and are disposed at intervals to form the elastic member.