Analysis of coupled vibration characteristics of PMS grinding motorized spindle
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DOI 10.1007/s12206-020-0802-3
Journal of Mechanical Science and Technology 34 (9) 2020 Original Article DOI 10.1007/s12206-020-0802-3 Keywords: · PMS motorized spindle · Bearing · UMP · Vibration
Correspondence to: Feng Gao [email protected]
Citation: Gao, F., Cheng, M., Li, Y. (2020). Analysis of coupled vibration characteristics of PMS grinding motorized spindle. Journal of Mechanical Science and Technology 34 (9) (2020) 3497~3515. http://doi.org/10.1007/s12206-020-0802-3
Received October 28th, 2019 Revised
May 28th, 2020
Accepted June 17th, 2020
Analysis of coupled vibration characteristics of PMS grinding motorized spindle Feng Gao, Mingke Cheng and Yan Li Lab. of NC Machine Tools and Integrated Manufacturing Equipment of the Education Ministry & Key Lab of Manufacturing Equipment of Shaanxi Province, Xi'an University of Technology, Xi’an, China
Abstract
Field-path-kinetic coupling and the multi-body dynamics models were established and the finite element method (FEM) was used to study the coupled vibrations of motorized spindle. The results show that the frequency is mainly 1fr at low speeds, fractional-octave and 1fr at high-speed only the bearing force. The orbit of bearing transitions is from a more pronounced circle to an approximately circular shape, while the rotor changes from a rule to a random pattern. The front bearing is more obvious than the rear and the orbits are always round; the radius of the orbit at the front bearing gradually increases as the speed increases. The result is the vibration displacement changes more significantly close to the spindle end and the amplitude increases accordingly. The experimental results show that operating conditions are closer to the normal, the influence of unbalanced magnetic pull can be neglected, the bearing selection and assembly are reasonable.
† Recommended by Editor No-cheol Park
1. Introduction
© The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature 2020
The high-speed, high-precision motorized spindle is the core component of CNC machine tools. It integrates “primer-drive mechanism-actuator-control system” to achieve near zero transmission and has compact structure, rotary precision and mechanical efficiency [1, 2]. In actuality, when the rotational speed of the motorized spindle reaches a certain value, the natural frequency of the spindle itself coincides with its forced vibration frequency and causes resonance. At the same time, the vibration caused by many factors such as manufacturing, assembly precision, rotor eccentricity and other factors directly affects the spindle precision, reducing the geometric error, surface quality and roughness of the machined parts [3, 4]. Angular contact bearings are the key support components of high-speed motorized spindle; and directly connected to the spindle and the housing, they have complex static and dynamic characteristics [5]. The bearing stiffness exhibits strong time-varying characteristics and nonlinear characteristics under complex conditions,
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