International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 06 | Jun 2025
p-ISSN: 2395-0072
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Dynamic Analysis of a Spindle with Different Bearing Specifications by Experimental and Computational Modeling Approaches Zhen-Yi Chen1, Guan-Chen Yu1, Guan-Hao Chen1, Jui-Pin Hung 1* 1Dept. of Mechanical Engineering, National Chin-Yi University of Technology,
Taichung 411030, Taiwan (R.O.C.) ---------------------------------------------------------------------***--------------------------------------------------------------------preload [7-11]. For instance, Kim et al. [7] reported that a Abstract - This study investigates the influence of bearing higher bearing preload can enhance spindle accuracy, but it specifications on the dynamic characteristics of a milling may also lead to a significant temperature rise. Therefore, spindle through both experimental measurements and finite preload levels must be carefully adjusted according to the element modeling. Bearing configurations were defined by specific cutting conditions. In a related study, Li and Shin the number and diameter of rolling elements, contact confirmed that increases in bearing temperature can alter geometry of the raceways, and preload conditions. the preload, thereby affecting the vibration characteristics Frequency response functions (FRFs) were experimentally of the spindle system [12]. obtained via impact tests on spindle units with varying bearing setups. Modal parameters—such as natural In bearing dynamics, parameters such as ball frequency, damping ratio, and compliance—were extracted diameter, number of balls, and overall bearing dimensions from the FRFs and analyzed in relation to bearing design. A (including inner and outer ring diameters) play a critical finite element model incorporating Hertzian contact theory role in determining bearing performance—particularly in was developed to simulate spindle dynamics and predict terms of stiffness, vibration characteristics, and loadbearing stiffness. The results show that changes in bearing carrying capacity [13]. These factors affect how the bearing rigidity, particularly when switching from larger to smaller interacts with applied loads, influencing stress distribution, bearings, significantly affect the spindle’s dynamic response. noise and vibration generation, and overall service life. Bai The simulated FRFs exhibit good agreement with et al.[14] demonstrated that variations in ball diameter experimental data, with discrepancies limited to significantly affect the sound radiation characteristics of approximately 5%. These findings demonstrate the full ceramic bearings, with the impact becoming more importance of bearing selection in tuning spindle pronounced at higher rotational speeds. In a separate performance and validate the proposed modeling approach study, Deng et al. [15] identified ball diameter as the most as a tool for the design and integration of machine tool sensitive structural parameter influencing the dynamic structures. stability and vibration behavior of ball bearings, followed by groove curvature radius and raceway diameter. A recent Key Words: Dynamic compliance, Dynamic characteristics, investigation by Deng et al. [16] further examined the Frequency response functions, High speed spindle effects of raceway diameters and guiding clearances on dynamic bearing stiffness. Their findings indicate that both 1. INTRODUCTION ball diameter and the number of balls, in combination with The spindle system is one of the most critical different raceway diameters, influence contact loads, components in machine tools, as its performance directly contact angles, contact deformations, and offset distances, influences both the machining capability and precision. thereby altering bearing stiffness. They concluded that a According to the research conducted by Choi and Lee [1], balanced combination of inner and outer raceway more than 50% of the structural deformation at the cutting diameters is essential to achieve both favorable stiffness point during machining originates from the spindle– magnitude and minimal stiffness fluctuation. bearing system. As such, enhancing the rigidity of the In general, bearings with smaller contact angles offer spindle system is considered one of the most effective ways improved resistance to radial loads and higher radial to improve the overall stiffness of machine tools. Several stiffness. Larger balls provide increased contact area, studies [2-6] have demonstrated that the dynamic behavior reducing elastic deformation at the ball–raceway interface of a spindle–tool system is largely governed by the and enhancing both contact stiffness and overall bearing characteristics of the supporting bearings. Among various rigidity. Additionally, a higher number of balls contribute options, angular contact ball bearings are the most to increased stiffness and load-carrying capacity. Tighter commonly used in spindle systems due to their low friction groove curvature (i.e., smaller clearance) results in greater and their capacity to support both axial and radial loads. contact stiffness, and an optimized curvature ratio is The key factors influencing spindle rigidity include beneficial for improving rigidity and minimizing bearing size and specification, arrangement, span, and deformation.
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