Optimisation of Hydrostatic Slideways Including Structure Elasticity

Summary

The total stiffness of a hydrostatic slideway (especially with counteracting pads) depends on both the bearing and the structure stiffness; if we have a given space for the system, an increase of structure stiffness obtained by increasing its size involves a reduction of the available bearing areas and consequently of the bearing stiffness itself; an optimum configuration giving maximum total stiffness must then exist.

A computer program has been developed in order to calculate the total stiffness of each configuration under test; the procedure starts by optimising the bearing stiffness for rigid bodies, by computing structure deflections caused only by fluid pressures with no external load and by changing restrictor values in order to maintain the predetermined optimum restrictor ratios.

An external load being applied, the new pressure distributions and the associated structure deflections are computed by iterative methods and the final attitude is determined.

The computer results obtained have been analysed and design criteria have been drawn up which may be used by technicians in order to achieve nearly optimum solutions, with no need of large computing facilities.

The same program may be used for computer-aided design. These methods have been developed in the design of a hydrostatic slideway to be used for fine boring operations on transfer lines.