Trend of modern development of machine tools lathe group is the use of multiple tool holders, multi-position turrets. This makes it necessary to determine the radial stiffness in the area of treatment in all possible directions of load. In this paper, we propose a method and a method of control stiffness spindles lathes using load device, which allows to determine the static radial stiffness of the spindle assembly when the direction of the vector load. The load device is a cylindrical mandrel with a conical shank. The mandrel is set in a tapered hole of tailstock quill. The angular position of the load lock device corresponds to the direction of the force. The principle of operation of the device is to provide a radial load on the spindle caused by the elastic deformation of the sliding mandrel load device stops the inner conical surface of the spindle. Mandrel previously spanned. This allows to estimate the radial load created by bending mandrel controlled indicator secured thereon. The dimensions of the mandrel are determined finite element modeling depending on the inner cone of the front end of the spindle and the required radial loads. For the experiment was selected eight positions mandrel: the direction of the force was varied by rotating the load device in the bushing at an angle of 45 degrees. According to the results of the experiment was built hodograph elastic displacement of the spindle. Analysis of the results showed that there is a significant change in the stiffness of the spindle bearings depending on the direction of the load, that is experimentally confirmed anisotropy stiffness bearing spindle assembly.

Keywords: lathe, spindle assembly, rigidity, stiffness anisotropy, load device, finite element method, strain hodograph