Actuator cylinder for folding stay bar and folding stay bar structure

The invention discloses an actuator cylinder for a folding stay bar and a folding stay bar structure. The actuator cylinder is of a sleeve type structure, and an oil way is arranged on the side wall of a cylinder barrel; a bush which can bi-directionally move relative to a piston rod is arranged at one end of the piston rod, and an elastic element is arranged between the bush and the cylinder barrel. When a rodless cavity of the actuator cylinder has no oil pressure, the piston rod and the bush can completely extend out by the spring force; when the rodless cavity of the actuator cylinder applies pressure, the oil pressure overcomes the spring force to drive the piston rod and the bush to realize the withdrawal function of an eyebolt at the end part. The folding stay bar of the actuator cylinder structurally comprises the actuator cylinder. A rotary joint with an inlet and outlet oil way is integrated in an earhole in the end of the cylinder barrel, and a spring is integrated on the actuator cylinder, so that the structure is simplified, the layout space of a pipeline, the joint and the external spring is omitted, the system weight is reduced. The actuator cylinder can be applied to the folding stay bar structure with a narrow space, strict weight control and need for unfolding locking.