Aiming at the issue of inaccurate design of multistage spiral pair structures due to the inaccuracy of the traditional transmission efficiency calculation formula for double-screw swinging hydraulic cylinders, which are used in steering gear, a new transmission efficiency calculation formula for these cylinders is proposed through mathematical modeling and dynamic analysis. Corresponding flexible dynamic and rigid dynamic simulation models of the double-screw swinging hydraulic cylinder are established to investigate the output characteristics, load startup characteristics, and maximum torque of the spiral pair. The accuracy of the flexible dynamic model and the rigid dynamic model is compared, and an experimental validation is conducted using a hydraulic test bench. The following conclusions are drawn: the calculation accuracy of the new transmission efficiency formula is improved by 21% compared to the traditional formula; under rated load pressure, the output torque accuracy of the flexible dynamic simulation model is improved by 55%. The flexible dynamic simulation model's closer alignment with experimental results proves its necessity. The research offers new simulation tools and a theoretical basis for the development of high-precision efficiency prediction models, holistic design, and optimization of double-helical oscillating hydraulic cylinders for underwater equipment.
Liu et al. (Tue,) studied this question.