The rack and pinion structure of the SB series swing hydraulic cylinder converts the linear motion of the hydraulic cylinder into the rotary motion of the actuator. The hydraulic cylinder has a compact structure, reliable transmission and a high degree of automation. It also has two installation forms of flange and tripod and two connection forms of shaft and hole. The special structure of single and double racks can meet the needs of different working conditions. The optional swing angle makes product selection more convenient. With sensors, Hefu valves, and digital cylinder modules, it can precisely control the swing cylinder at any angle. This product is suitable for metallurgy, mining, steel plant, machinery, military, environmental protection, hydropower and other fields.