Tolerance analysis in valve design
Research Task/Objectives
Used procedure for analysis and synthesis of tolerances on fluid power valves
In general, all characteristics of a valve may vary from piece to piece due to manufacturing variations, variations of material properties and environmental influences. The conscious exploit of the individual components design limits and the use of special material properties generally demand tighter tolerances in order to prevent a failure of the required functionality as a result of these variations. Nevertheless, the tolerances cannot be chosen arbitrarily tight for purposes of economical production.
Therefore, the aim is to identify suitable methods and tools for cross-domain tolerance analysis and for the systematic and knowledge-based definition of the tolerances allowed during valve design.
Approach/Results
The qualitative analysis of the transfer functions for typical valve structures allows for
the systematic identification of occurring noise factors. Their impact on the system behavior is identified through the Monte Carlo Simulation. The sensitivity analysis reveals
the most significant noise factors. Numerical optimization lends itself to automated tolerance synthesis, taking into account the production costs. The procedure is demonstrated for both a pneumatic as well as a hydraulic valve example.
The presented research activities are part of the project "Tolerance analysis in valve design" (Ref. No. 702850). The authors would like to thank the Fluid Power Research Fund of the VDMA for the funding and support.