Optimization Design Of Sealing On Servo Turret

Since the rotation and position of servo turret’s cutter are mainly controlled by the oil cylinder. The running stability of the servo turret is directly influenced by the cylinder’s sealing structure and the choice of sealing elements. Under the actual working condition which the piston rod reciprocates at least 20 times per minute and the oil pressure of 3.5MPa, analysis is made on the reciprocating sealing element between the piston rod and the cylinder to check on sealing element’s deformation, fatigue life, leakage and thermal field. Specific content and the research results are as follows:1. Compressive test on the sealing material was made, and the finite element (FE) model consisting sealing element, the piston and the cylinder, was established to study the influence of material hardness on the sealing performance. It is suggested that the sealing ring with Shore A hardness 90 performs better than that with hardness 95, which improved effective sealing time by more than 1.9 times, under the hydraulic pressure 3.5MPa.2. The heat generation is mainly caused by the mechanical hysteresis of the polymer materials and the friction between the piston and the sealing element. The temperature distribution within the sealing element was acquired through the thermal structure coupling analysis. The result showed that the heating generation of the mechanical hysteresis is more than that of friction. Under the pressure of 3.5MPa, the highest temperature of the Y-shaped sealing ring chosen for the turret is 61.7℃, that satisfies the requirement of allowable temperature.3. Based on the fluid dynamics theory, the sealing leakage rate was calculated by mathematical software Matlab and FE software Abaqus. The results showed that the influence of temperature on the sealing leakage should not be neglected, because temperature has a significant influence on the viscosity of the sealing medium. Proved that the choice of sealing ring with hardness HA90 in this turret is reasonable.4. According to the national standard GB/T1184, the effects of verticality and straightness on the sealing leakage and temperature were studied, within the unlabeled tolerance. Results of simulation showed that due to the hyperelasticity of the sealing material and the asymmetry of the section, geometric tolerance has a little influence on the sealing performance, which could be neglected.