The accuracy design of a new type of pin gauge annular slit restrictor based on the assembly success rate

Abstract

The restrictor is an indispensable compensation element in the constant pressure hydrostatic bearing. The annular slit restrictor has a direct impact on the throttling clearance due to the existence of machining error, which results in a low assembly efficiency. However, the assembly success rate can be increased by improving the machining accuracy, which increases the machining cost and machining cycle. To optimize the machining accuracy distribution of the restrictor, a closed-loop mixed-size chain tolerance model was established by considering the geometric tolerances. The influence of geometric error on the flow resistance of the traditional annular slit restrictor was analyzed by Worst Case analysis. The results show that the size error had the most significant effect on the flow resistance. The tilted state and eccentric state caused by geometric errors had little influence on the flow resistance. The existence of geometric errors will reduce the flow resistance. Based on the above research results, a new pin gauge annular slit restrictor, which has the advantages of a high precision and a low cost, was developed. Moreover, the influence of the installation conditions on the flow resistance was analyzed. The change in the flow resistance was reduced when the pin gauge was completely eccentrically installed. Additionally, the influence of the dimensional tolerance of the orifice on the success rate of the assembly was analyzed by the probability method. When the design tolerance of the orifice was ±4 μm, the success rate of the assembly reached 99.97%. Finally, the accuracy of the theoretical analysis results was verified by experiments.