DYNAMICAL ANALYSIS OF THE MECHANICAL VIBRATION SYSTEM «SPINDLE UNIT» OF MACHINE-TOOL

Abstract

Purpose. The research of complex influence of design, kitting, mounting and maintenance conditions of spindle units on natural frequencies array formation. Design/Methodology/approach. Spindle unit is considered as mechanical vibration system, which consist of subsystems: tool(tool holder), spindle and spindle quill that is elastically mounted on machine tool bed. Constraints of the system are: tool holder – spindle joint for first and second subsystems and support bearings for second and third subsystems. Method of dynamical compliances is used in order to work out balance equations in points of subsystems disconnection. Dynamical compliances are determined by using method of initial parameters in matrix form (method of transfer matrices). Four cases of system kitting are considered: spindle on supports; spindle on supports with connected tool holder; quill on supports with connected spindle; spindle unit (whole kitting). Findings. Natural frequencies of “spindle unit” system for four types of kitting, taking into account varying of the stiffness of bearings of the spindle supports and quill supports, are calculated. Originality/value. Results of analysis indicates about concrete regularity of natural frequencies array forming of the “spindle unit” system, that associated with spindle unit kitting. Design, mounting and maintenance conditions of spindle units defines nature of change of this natural frequencies.