Papers by Keyword: Bending Loading

Abstract: Ball screws and nuts represent the inseparable part of machinetool building. The thread lead accuracy ranges in hundredths of millimetres per 1 m. In addition to the undesirable phenomena caused by heat (dilatability) and, e. g., torsional and transverse oscillations, the bending stress of the ball screw is considerably undesirable too. This stress and at the same time behaviour are transferred to the bending stress of the ball screw nut. This has a very harmful influence on setting of the ball screws, when the machine tool is assembled. Using the analysis by means of the FEM method, the paper conducts a survey of deformation issue of the arrangement "machine – ball screw – ball screw nut" during the assembly stage as well as a survey of compensation possibilities and other technical measures determined to limit the undesirable deformations and stress of the ball screw originating already in the manufacturing stage of the machine tool.

Abstract: A series of ratcheting experiments under bending loading for Z2CND18.12 stainless steel were carried out on a dynamic mechanical analyzer. The characteristic of progressive inelastic deformation of the material in the different temperatures and different bending loadings were investigated. The difference of the domestic and imported stainless steel on the bending ratcheting properties was studied. It is shown that the temperature and the bending loading affect the ratcheting greatly. In addition, the imported steel is better than the domestic one on the resistance to the ratcheting deformation at various temperatures and bending loadings.