This paper presents a control method of a check ball in hydraulic L-shaped pipe by Magnus force. The spring-driven ball-type check valve is one of the most important components of hydraulic systems; it controls the position of the ball and prevents backward flow. In this paper, the relationship between the position of the inlet pipe and the ball levitation time is evaluated using CAE. The check ball is arranged as a check valve in the L shape piping of the hydraulic cylinder. By moving the position of the inflow pipe from the center of the housing, a strong swirling flow is generated in the entire housing to give rotational motion to the check ball. Magnus force was exerted by this rotation and it was found that the levitation time was advanced. The check ball is supported by a spring to ensure the check operation. However, the spring must be eliminated due to various problems. This causes the check ball to rotate and translate. In the experiment, it is difficult to confirm the behavior of the check ball and the detailed flow around it. The purpose of this study is to clarify the effect of the Magnus force acting on the rotation of the check ball by using CAE tool. It was found that there is a difference in the time to check depending on the rotation direction and rotation speed of the check ball.
Poppet valves are often used as a pressure / flow rate control valve for a hydraulic system. Much research has been conducted on the characteristics of poppet valves. Hysteresis characteristics have emerged in pressure-flow characteristic experiments of poppet valves designed and prototyped by the author. In order to clarify the mechanism of this hysteresis characteristic, we firconfirmed the reproduction of hysteresis and confirmed the validity of the research policy. Specifically, we investigated the internal flow by CFD analysis and examined the reproduction of hysteresis characteristics by CFD. The CFD software used is Simerics MP +, which allows CFD analysis to be combined with the valve's equation of motion. First, the precision of CFD analysis was verified by confirming that the experimental values of in the reference and calculated values were in good agreement. Furthermore, CFD steady flow analysis of the internal flow was performed, and the validity of the calculation results such as the flow patterns, flow coefficient, and flow force was examined. As a result, it was clarified that there is a flow pattern that can be roughly divided into two types of internal flow with different flow rates. Then, by changing the flow rate in a time-dependent manner using CFD, we were able to reproduce the hysteresis characteristics that are in good agreement with the experimental results.
A laminar flow resistance in a pipe is usually used as a representative model of flow resistance because it is convenient to use and often gives reasonable resistance value in a small size pipe under steady state condition. However, the laminar flow resistance model in a pipe is not applicable in an oil flow passage of a real circuit because a flow passage has complex shape in a real circuit. Furthermore, the mathematical model of fluid column in a pipe made in inviscid flow condition is often used as an inertial model in considering dynamic condition. In the real condition of operating oil-hydraulic circuit, the above mentioned two effects, a complex shape of flow passage and flow dynamic characteristics, appears in viscous flow condition. A new model or modeling method to include and solve these effects reasonably becomes necessary. A new modeling method using CFD is introduced in this paper.