Judgment of Liquid Flowing State in Hydraulic Cylinder System

The flow state of liquid is generally laminar and turbulent, and the industry is judged by the Reynolds number. The Reynolds number is represented by the Re symbol, and the Reynolds number when the liquid flows in the hydraulic pipe is expressed by the mathematical formula: (RE=vd/y) In the formula, d represents the diameter of the pipe flowing through; v is the velocity of liquid flow; y Is the kinematic viscosity of the liquid. The state of liquid flow, the condition of turning laminar flow into turbulent flow is determined by the critical Reynolds number. When the Reynolds number Re is less than the critical Reynolds number Re0, it is laminar flow, and when it is greater than Re0, it is turbulent flow.

From the analysis of physical principles, the forces affecting liquid flow are mainly inertial force and viscous force. This laminar and turbulent state, simply said that the Reynolds number is large, indicating that the inertial force plays a leading role, and the liquid flow is in a turbulent state. , When the Reynolds number is small, it means that the viscous force plays a leading role, and the liquid flow is laminar.

　　The hydraulic cylinder support bushing is inserted in the groove of the inner diameter of the guide sleeve, and the support bushing plays a role in guiding and supporting the piston rod.

　　The inner diameter of the support bushing and the outer diameter of the piston rod are controlled within 0.08-0.16mm, which is the most ideal design gap. Less than 0.08mm, the piston rod movement resistance will be large, the cylinder will tremble, the support bushing will wear faster, and in severe cases, there will be abnormal noise, and the support will be lost; when the gap exceeds 0.16mm, it will easily cause eccentric wear with the piston rod. Unilateral force on the bushing causes leakage in the cylinder and the piston rod with oil. The best gap between the outer diameter of the support bushing and the inner diameter of the cylinder barrel should be controlled within 0.1-0.19mm. When it is less than 0.1mm, the resistance of the piston rod during movement will be relatively large, and the uniform speed of movement cannot be maintained. In addition, friction heats up during movement, thermal expansion and contraction, and the temperature of the piston rod and the support bushing relative to the cylinder is high, so the movement resistance Will also increase. When the gap is greater than 0.19mm, the bushing will not play a supporting role, and the baffle on the piston rod or the outer edge of the piston will easily scratch the cylinder and cause the cylinder to be scrapped. The assembly gap should be adjusted by the support bushing.