汇报题目：IMECE 2017 参会报告

汇报时间：2017年11月14日（星期二）9:30-12:00

汇报地点：曲江校区西二楼315会议室

汇报人：张燕飞，方斌，万少可，孙岩辉，陈剑

会议信息

会议名称：IMECE 2017

会议时间：November 2—November 9, 2017

会议地点：Tampa Convention Center, Tampa, Florida, USA

会议简介：ASME’s International Mechanical Engineering Congress and Exposition (IMECE) is the largest interdisciplinary mechanical engineering conference in the world. IMECE plays a significant role in stimulating innovation from basic discovery to translational application. It fosters new collaborations that engage stakeholders and partners not only from academia, but also from national laboratories, industry, research settings, and funding bodies.

会议交流工作：

Presentation：

Rotation accuracy analysis of spindle under variable preload(汇报人：张燕飞)

Investigation of Optimizing Arrangement Forms for Combined Angular Contact Ball Bearings(汇报人：方斌)

Measurement of Dynamic Performance of High-speed Rotating Spindle by Non-contact Electromagnetic Loading Device(汇报人：万少可)

An Analysis Model to Predict Rotation Accuracy of High-Precision Spindles Considering Part Errors and Deformation (汇报人：孙岩辉)

Micro-contact Models for Metallic Line-contact Based on Measured Surface Profile(汇报人：陈剑)

参会论文信息：

Title:Rotation accuracy analysis of spindle under variable preload

Author:Yanfei Zhang, Z Xiaohu Li , Jun Hong, Sun’an Wang, Baotong Li，Yanhui Sun

Abstract:

Variable preload technology is used to achieve appropriate preload applied on spindle bearings based on machining conditions. However, the bearing temperature rise will directly affected by the bearing preload as well as the bearing rotation accuracy. So, the main objective of this paper is to propose a method to determine the rotation accuracy of the spindle affected by the thermal expensive due to heat generation under variable preload. Five degrees of freedom (5-DOF) quasi-static model of angular contact ball bearing under variable preload was established to investigate the internal load distribution of the contact area between the race way and balls. Then local contact heat generation of the bearing is calculated based on hertz contact theory. Then an experimental platform equipped with hydraulic system is designed and fabricated, which is preload by the hydraulic chamber. Studies have shown that the rotation accuracy presents drastically with the rotational speed. Moreover, the influence of the bearing preload has a secondary importance. Comparative analysis about the rotation accuracy between starting running and stable running after a few hours under the same preload is investigated. The results show that the accuracy of rotation spindle presents no obviously difference subject the uneven thermal deformation of parts in the spindle system.

Title：Investigation of optimizing arrangement forms for combined angular contact ball bearings

Author：Bin Fang，Jinhua Zhang，Jun Hong，Yongsheng Zhu，Xu Wang，Jiajia Gao

Abstract：

The combined angular contact bearings are widely used in numerous rotating machinery system, but few research works on the combined angular contact ball bearings have been reported. To solve the problem about inconsistency fatigue life of the bearings in the combined bearings with asymmetric arrangement, this paper proposed a special combined bearings arrangement form in which the bearings with different contact angles are used simultaneously for the bearing combination. In order to validate the effectiveness of the proposed method, a mathematical model is proposed to analyze the load distribution, life and stiffness of the combined bearings, and the combined bearings with three different arrangements are comparatively calculated and analyzed. The results show that the whole life of combined bearings is mainly depend on the life of the bearing under heavy load, and the new arrangement form in which the initial contact angle of the bearing under heavy load is increased that can improve the whole life of combined bearings.

Title:Measurement of Dynamic Performance of High-speed Rotating Spindle by Non-contact Electromagnetic Loading Device

Author:Shaoke Wan, Jun Hong, Wenjun Su, Xiaohu Li, Yanhui Sun, Wei Chen

Abstract:

When spindle rotates, the stiffness and natural frequency that reflect the dynamic performances of spindle system, vary with different rotating conditions. Therefore, the measurement of stiffness and natural frequency is highly needed. However, it is difficult to apply excitation to the rotating spindle during the measurement. In this paper, a non-contact electromagnetic loading device is developed to provide desirable excitation for the measurement. Next, an experimental spindle test rig with constant pressure preload is established. With the help of the proposed loading device, stiffness and natural frequency of the experimental spindle at different rotating states are measured. Finally, the effects of rotation speed and temperature on the natural frequency and stiffness of spindle are discussed based on the measurement results. The results show that the rotation speed and temperature have the similar influence trend on the measured spindle’s softening.

Title：An Analysis Model to Predict Rotation Accuracy of High-Precision Spindles Considering Part Errors And Deformation

Author：Yanhui Sun, Jun Hong, Junkang Guo, Yanfei Zhang, Shaoke Wan, Shuai Zheng

Abstract:

High-precision spindles have significant influence on the machining precision and finishing quality largely due to their motion errors. However, the analysis of rotation accuracy is quite not easy in design stage because of the neglecting of geometric errors and deformations of parts in the traditional dimension chains. Hence, a theoretical analysis model is built in present study to do the prediction. The 3D error accumulation path is recognized by Datum Flow Chain (DFC) and the key tolerances are modeled by Small Displacement Torsor (SDT). Thereafter, the variation propagation is conducted by Homogeneous Transformation Matrices (HTM) and the geometric misalignment in the spindle is calculated. Then, an FEA model is built with Timoshenko beam elements and the deformation is calculated after the geometric misalignment is applied to the model. As spindle rotates, the trajectory of the spindle nose is obtained. Finally, the Monte Carlo (MC) method is used to get the distribution and the range of motion errors. To verify the feasibility and reliability of the analysis model, the radial and axial motion errors of a double supported high-precision spindle are analyzed.

参会论文信息：

Title:Micro-contact Models for Metallic Line-contact Based on Measured Surface Profile

Author:Jian Chen, Jun hong, Jinhua Zhang, Linbo Zhu, Zhigang Liu

Abstract:

In order to study the dry rough line-contact mechanism between two longitudinally rough metallic surfaces, the measured profile is mathematically described by quadratic functions for the application of the existing micro-contact models. The mechanical parameters are determined using the different approximating criteria. Next, based on these deterministic parameters, different micro-contact models are employed and extended to predict the characteristics of a line contact. Comparison of different theoretical calculation results reveals that the greater maximum values of the contact deformation and the ratio of real to nominal contact area are predicted by the Hertz model as compared to the micro-contact models considering the elastoplastic deformation, and that the KE (Kogut and Etsion) and JG (Jackson and Green) models predict closer results. It is also found that when the rough surfaces are described by quadratic functions according to the same area criterion or same root mean square (RMS) criterion, the line-contact responses between them prescribed by any micro-contact models have the same tendency.