Dynamics of Machine Tool Spindle/Bearing Systems Under Thermal Growth

1997 ◽  
Vol 119 (4) ◽  
pp. 875-882 ◽  
Author(s):  
Bert R. Jorgensen ◽  
Yung C. Shin
Keyword(s):  
Thermal Expansion ◽  
Dynamic Response ◽  
Heat Generation ◽  
High Speed ◽  
Transfer Model ◽  
Good Prediction ◽  
High Speeds ◽  
Spindle Bearing ◽  
Thermal Growth ◽  
Bearing Stiffness

Increased use of high-speed machining creates the need to predict spindle/bearing performance at high speeds. Spindle dynamic response is a function of the nonlinear bearing stiffness. At high speeds, thermal expansion can play an important role in bearing stiffness. A complete bearing load-deflection analysis including thermal expansion is derived and is coupled with an analysis of spindle dynamic response. Steady-state temperature distribution is found from heat generation at the contact point and from a quasi three-dimensional heat transfer model. Numerical solutions give a good prediction of thermal growth and heat generation in the bearing. Predicted high-speed spindle frequencies show good agreement with experimentation. The effects of loading condition and bearing material type on bearing stiffness are also shown.

Integrated Dynamic Thermo-Mechanical Modeling of High Speed Spindles, Part 2: Solution Procedure and Validations

2004 ◽  
Vol 126 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Hongqi Li ◽  
Yung C. Shin
Keyword(s):  
High Speed ◽  
Solution Procedure ◽  
Operating Conditions ◽  
Test Results ◽  
Mechanical Modeling ◽  
Spindle Bearing ◽  
Wide Range ◽  
Bearing Stiffness ◽  
Models Validation ◽  
Validation Tests

This paper presents a new solution procedure for an integrated thermo-dynamic spindle model and validation results. Based on the model presented in Part 1 of this paper, a computer program has been developed to generate comprehensive solutions for high speed spindle-bearing systems, such as bearing stiffness, contact load and temperature, spindle dynamic characteristics and response, temperature distributions, and thermal expansions. The model and the solution procedure are modular such that solutions for different spindle set-ups can be easily generated by combining a given spindle model with different toolholder models. Validation test results for thermal and dynamic predictions are presented for four different spindle systems, including the thermal and dynamic validation tests on a specially constructed spindle testbed. The validation results show the model has accurate predictive capabilities for a wide range of operating conditions and various spindle designs.

Analyzing characteristics of high-speed spindle bearing under constant preload

2017 ◽  
Vol 232 (5) ◽  
pp. 568-581 ◽  
Author(s):  
Thi-Thao Ngo ◽  
Van-The Than ◽  
Chi-Chang Wang ◽  
Jin H Huang
Keyword(s):  
Film Thickness ◽  
Thermal Effects ◽  
High Speed ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Lubricant Film ◽  
Contact Forces ◽  
Transfer Model ◽  
Lubricant Film Thickness ◽  
Spindle Bearing

Bearings play an important role in a high-speed spindle. Its characteristics are often influenced by speed and thermal effects. This paper presents an approach that combines an inverse method with a high-speed ball bearing model to determine the characteristics of a high-speed spindle bearing under constant preload in actual working conditions. With temperature distribution in the entire spindle obtained by the experimental inverse heat transfer model from the authors’ previous results, the change in bearing parameters is then calculated and subsequently replaced in the bearing model to analyze the change in bearing characteristics. As a result, thermal effects on a bearing’s dynamic contact angles, contact forces, contact stress, stiffness, and lubricant film thickness are presented. Moreover, analysis results indicate that a bearing’s stiffness and lubricant film thickness nonlinearly vary with the increase in speed, and the thermal effect significantly affects the lubricant film thickness. The results presented herein may be applied to develop a dynamic model for a high-speed spindle using a constant preload and provide useful information to avoid failure in lubrication.

An Integrated Approach Toward the Dynamic Analysis of High-Speed Spindles: Part I — System Model

1993 ◽  
Author(s):  
C. H. Chen ◽  
K. W. Wang ◽  
Y. C. Shin
Keyword(s):  
High Speed ◽  
Integrated Approach ◽  
Ball Bearings ◽  
Basic Principles ◽  
Gyroscopic Moment ◽  
High Speeds ◽  
Modeling Process ◽  
Radial Stiffness ◽  
Bearing Stiffness ◽  
Made In

Abstract Experimental evidence [Shin, 1992] has shown that the natural frequencies of high speed spindles with angular contact ball bearings decrease with increasing rotational speed. A recent study [Wang, et al., 1991] illustrated that this phenomenon is caused by stiffness change of the bearings. A simplified approximation was used in the analysis to examine the bearing radial stiffness at high speeds. While the investigation explained the experimental observations in a qualitative sense, the analytical results so far are not sufficient to quantitatively describe the spindle behavior under high speed operations due to the approximations made in the modeling process. This paper presents an integrated approach toward the modelling of flexible spindles with angular contact ball bearings from basic principles. The local dynamics of the bearings are coupled with the global shaft motion. The model derived includes both the longitudinal and transverse vibrations of the shaft interacting with the nonlinear bearings. The influences of shaft speed on the bearing stiffness matrix and the system frequencies have been studied. It is shown that the spindle dynamic behavior can vary substantially as speed increases due to the bearing gyroscopic moment and centrifugal force. These effects have been ignored in most of the previous spindle models. Lab tests were conducted to validate the model. The analytical predictions are quantitatively verified by the experimental results.

scholarly journals Thermally affected stiffness matrix of angular contact ball bearings in a high-speed spindle system

2019 ◽  
Vol 11 (11) ◽  
pp. 168781401988975
Author(s):  
Dinh Sy Truong ◽  
Byung-Sub Kim ◽  
Jong-Kweon Park
Keyword(s):  
Thermal Expansion ◽  
Stiffness Matrix ◽  
High Speed ◽  
Structural Model ◽  
Ball Bearings ◽  
Spindle System ◽  
Spindle Shaft ◽  
Ball Surface ◽  
Bearing Stiffness ◽  
Coupling Stiffness

Bearing stiffness directly affects the dynamic characteristics in a high-speed spindle system and plays an important role in terms of manufacturing quality. We developed a new approach for predicting the thermal behavior of a high-speed spindle, calculated the thermal expansion, and generated a bearing stiffness matrix for angular contact ball bearings. The heat convection of spindle housing in air, the balls in lubricant, the spindle shaft in quiescent air, and the bearing inner ring surfaces were determined. Heat sources such as bearing friction, and the heat contributed by the built-in motor, were simulated using an analysis systems (ANSYS) steady-state thermal model. The results were imported into a static ANSYS structural model. Ball thermal expansion was calculated based on changes in the coordinates of nodal points on the ball surface. Finally, a thermally affected bearing stiffness matrix was generated by applying the Newton–Raphson technique. Decreases in the bearing radial, axial, angular, and coupling stiffness values as rotational spindle speed increased were calculated. Also, the stiffness coefficients at a specific speed increased significantly caused by the thermal effects. Finally, for validation, the bearing stiffness was compared to that calculated using an earlier thermal network approach.

scholarly journals Speed Effects on Inherent Rotating Frequency of Motorized Spindle System

2011 ◽  
Vol 2-3 ◽  
pp. 900-905 ◽  
Author(s):  
Bo Wang ◽  
Wei Sun ◽  
Kun Peng Xu ◽  
Bang Сhuan Wen
Keyword(s):  
Centrifugal Force ◽  
High Speed ◽  
Impact Factors ◽  
Motorized Spindle ◽  
Spindle System ◽  
High Speeds ◽  
Radial Stiffness ◽  
Bearing Stiffness ◽  
Coupling Factors ◽  
The Impact

The paper determines the impact factors of high-speed spindle system including the centrifugal force, gyroscopic moments and the bearing stiffness softening, etc, then builds the general spindle-bearing FEM considering high speeds. Taking a motorized spindle as example, the effect of centrifugal force, gyroscopic effect, the radial stiffness and the coupling factors are analyzed qualitatively and quantitatively. Finally the research shows the variations of bearing radial stiffness, centrifugal force and gyroscopic moments have a significant effect on dynamics of spindle system in high speeds, while modeling the high speed spindle system, above factors must be considered.

scholarly journals Research on the influencing factors of thermal characteristics of high-speed grease lubricated angular contact ball bearing

2021 ◽  
Vol 13 (6) ◽  
pp. 168781402110273
Author(s):  
Chang Zhang ◽  
Dan Guo ◽  
Jiyin Tian ◽  
Qingbo Niu
Keyword(s):  
Thermal Expansion ◽  
Heat Generation ◽  
High Speed ◽  
Ball Bearing ◽  
Thermal Characteristics ◽  
Generation Model ◽  
Analysis Model ◽  
Angular Contact Ball Bearing ◽  
Bearing Contact ◽  
Contact Parameters

The high temperature rise of grease lubricated angular contact ball bearing under high speed operation will affect the working accuracy of the bearing, and even lead to the loss of accuracy. In this paper, a friction heat generation model for high-speed grease lubricated angular contact ball bearing was established. Based on the quasi-static analysis model, the thermal expansion of the bearing components is brought into the quasi-static equilibrium equation, and the modified quasi-static analysis model of high-speed grease lubricated ACBB is obtained. Under grease lubrication conditions, a local bearing heat-generation model was employed to assess power losses in different contact zones, in which bearing contact parameters, external loads, and rotation speeds conditions were fully considered. Moreover, the temperature distribution of grease lubricated high-speed bearing was analyzed by the multi node thermal network method. Through the analysis model of bearing dynamic and thermal characteristics considering the influence of thermal expansion established, bearing contact parameters have significant differences. The calculated values of outer ring temperature of grease lubricated angular contact ball bearing is in good agreement with the experimental values. The model can predict the temperature values of grease lubricated angular contact ball bearing under axial load at high speed.

Dynamics of Spindle-Bearing Systems at High Speeds Including Cutting Load Effects

1998 ◽  
Vol 120 (2) ◽  
pp. 387-394 ◽  
Author(s):  
Bert R. Jorgensen ◽  
Yung C. Shin
Keyword(s):  
Natural Frequency ◽  
High Speed ◽  
Dynamic Models ◽  
Complex Geometry ◽  
Beam Theory ◽  
Coupled System ◽  
Influence Coefficient ◽  
High Speeds ◽  
Spindle Bearing ◽  
Influence Coefficient Method

Increased use of high speed machining creates the need to predict spindle-bearing performance at high speeds. Previous spindle-bearing models simplify either spindle or bearing dynamics to the extent of prohibiting a detailed analysis of a spindle with high speed motion. At high speeds, centrifugal loading in the bearing causes stiffness softening, creating a change in natural frequency. Therefore, spindle modeling requires a comprehensive representation of the dynamics of shafts with complex geometry rotating at high speeds and supported by non-linear bearings. This paper presents a coupled system of spindle and bearing dynamic models with numerical solution. Spindle dynamics are modeled using the influence coefficient method of discrete lumped masses, based on Timoshenko beam theory. Both linear and rotational bearing stiffness are included in the spindle model through solution of the angular-contact bearing model. The parameters of cutting loads, tool mass, and rotational speed are analyzed, and all are shown to affect the natural frequency. The computer model is both rapid and robust, and shows excellent agreement with experimental analysis.

scholarly journals Study on Dynamic Response of Assembly Type Gear-Rotor System

2011 ◽  
Vol 2-3 ◽  
pp. 912-917
Author(s):  
Ji Shuang Dai ◽  
Peng Zhang ◽  
Chao Feng Li ◽  
Bo Wang ◽  
Bang Chun Wen
Keyword(s):  
Dynamic Response ◽  
Working Conditions ◽  
High Speed ◽  
Critical Speed ◽  
Rotor System ◽  
Coupled Systems ◽  
Tilting Pad ◽  
Bearing Stiffness ◽  
Unbalance Force ◽  
Stiffness Characteristics

The dynamic model of a rotor system of assembled compressor is established. Based on the single axis analysis, and considering the tilting-pad bearing stiffness characteristics with speed variations, the paper analyses whole system’s nature characteristic with gearing mesh factors. It mainly expands with the form of amplitude-frequency drawing and spectrum charts, and examines the dynamic response with each key position of coupled systems under the two working conditions. The results show that, because of the existence of gear meshing effect, Low speed axis and high-speed axis in the corresponding speed shaft appeared a few larger vibration amplitudes, at high speed axis add unbalance force, can arouse resonance of this axis in the first two order critical speed, but in the other axis don’t have obvious display.

scholarly journals Effect of preload on the dynamic characteristics of ceramic bearings based on a dynamic thermal coupling model

2020 ◽  
Vol 12 (1) ◽  
pp. 168781402090385
Author(s):  
Ke Zhang ◽  
Zinan Wang ◽  
Xiaotian Bai ◽  
Huaitao Shi ◽  
Qi Wang
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Thermal Deformation ◽  
Coupling Model ◽  
Transfer Model ◽  
Thermal Coupling ◽  
Motorized Spindle ◽  
Rotating Speed ◽  
Spindle Bearing ◽  
Bearing System

Ceramic bearings have a good dynamic output performance under an ultra-high, ultra-low temperature due to their small deformation property. Based on the Harris and Palmgren empirical equation, this article establishes the thermal transfer model of a ceramic motorized spindle. The thermal deformation of a ceramic angular contact ball bearing is calculated. A dynamic and thermal coupling model of the ceramic motorized spindle is built using the Hertz contact theory, which can determine the optimal preload force under different rotating speed conditions. The influence of different temperatures, preload, and rotation speeds on the bearing vibration characteristics was studied. The accuracy of the dynamic and thermal coupling model was verified by the motorized spindle experimental platform. The results show that the thermal deformation of the bearing is an important influencing factor for the output of the dynamic characteristics. Considering the thermal displacement of the bearing, the simulation accuracy of the ceramic motorized spindle-bearing system is in good agreement with the experimental results. By adjusting the bearing preload, the parameters of the rotating speed can effectively reduce the temperature rise and suppress the vibration. The spindle-bearing system model provides a theoretical basis for the dynamic development of a high-speed ceramic bearing.

Minimization of Transient Temperature Fluctuations in High Speed Spindle Bearing

2014 ◽  
Vol 592-594 ◽  
pp. 1114-1118
Author(s):  
Venugopal Prabhu Raja ◽  
P. Pal Pandian ◽  
Devara Venkata Krishna ◽  
R. Sathiya Moorthy
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Behavior ◽  
Heat Generation ◽  
Temperature Rise ◽  
High Speed ◽  
Temperature Fluctuations ◽  
Transient Temperature ◽  
Element Analysis ◽  
Spindle Bearing

The performance of a high speed spindle is mainly attributed to the thermal behavior of spindle bearings. Hence, it is very significant to simulate the thermal behavior of spindle bearings. Finite element analysis is carried out for a typical high speed spindle by considering bearing and motor heat generation under various loading conditions to investigate the transient temperature rise of the spindle assembly. The influence of different cooling arrangements on the thermal behaviour of spindle bearings is then investigated with the objective of minimization of transient temperature fluctuations.

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