高速磨削电主轴温升及动力学特性研究
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摘要
以高切削速度、高进给速度、高加工精度为主要特征的高速切削和高速加工是当今先进制造技术之一。高速高精度数控机床是实现高速加工的关键因素,而高速主轴是高性能机床的核心部件。随着电气传动技术的迅速发展和日趋完善,高速数控机床主传动系统的机械结构已得到极大的简化,基本上取消了带轮传动和齿轮传动。机床主轴由内装式电动机直接驱动,从而把机床主传动链的长度缩短为零,实现了机床的“零传动”。这种主轴电动机与机床主轴“合二为一”的传动结构形式,使主轴部件从机床的传动系统和整体结构中相对独立出来,因此可做成“主轴单元”,俗称“电主轴”。
电主轴单元的结构设计、热态特性和动态特性在很大程度上决定了高速数控机床的加工质量和切削能力,也是影响其加工精度的重要因素。对主轴单元进行热态特性和动态特性的研究,对进一步提高高速机床的工作性能有十分重要的意义。
本文以高速磨削类加工数控机床用电主轴为研究对象,以实现电主轴的高速、高精度为目标,采用有限元方法,运用ANSYS软件,对电主轴的热态特性和动态特性进行研究,具体工作如下:
(1)分析了电主轴的结构特点,对主轴电机、主轴轴承、轴承润滑系统、电机定子的油一水热交换系统等关键部件进行了研究;并针对电主轴结构中的一个重要设计参数——电机与主轴的过盈量配合进行了分析计算。
(2)分析了电主轴的传热机制,根据实际工况对电主轴工作时的热源及各部分的传热系数进行了计算,在此基础上,利用大型有限元软件ANSYS对本课题中所研究的主轴单元进行了热一结构耦合分析,研究了电主轴单元的温度场分布、主轴轴承的温升情况及主轴前端的热变形情况,并提出了抑制主轴温升的合理有效的措施。
(3)分析了电主轴单元中所采用的特殊轴承形式——角接触混合陶瓷球轴承的结构形式及高速运转下的受力及动态特性,对其刚度进行了计算,在此基础上对电主轴进行了动力学分析,并通过实验说明了轴承的预紧力对主轴单元固有频率的影响情况,为优化主轴结构和改善电主轴的动态特性提供必要的理论依据,为高速电主轴的研究开发和应用奠定了基础。
High speed cutting and high speed machining taking high cutting speed, high feed speed and high machining precision as main characters is one of advanced manufacturing technology nowadays. High speed NC machine tool with high speed and high precision is the key factor to realize the high speed machining. High speed spindle is the core component of a high-performance machine tool. With the fact that the promptness developing and. being perfected of the electric drive technology, systematic machinery of the high speed NC machine tool' main drive structure has already got extremely simplification, has canceled wheel drive and the gear drive mainly. The motorized spindle of machine tool is direct drove by a built-in motor, thereby; the main transmission chain length of machine tool has been shortened for zero, and realized "zero transmission" of machine tool. That the drive structure form of the motorized spindle and motor "two combined into one" makes the motorized spindle component be independent relatively from the transmission system and the whole structure of the machine tool, be made as "the motorized spindle unit", the popular name "the motorized spindle" therefore.
To a great extent, the construction design, the thermal characteristics and dynamic performances of the motorized spindle determine machining qualities and cutting capabilities, and are the important factors influencing the precision of the high speed NC machine tool. It is important to study the thermal characteristics and dynamic performances of the motorized spindle on improving the performance of the high speed machine tool.
This paper takes the motorized spindle used in a high speed grinding machine tool as the study object, realizing high speed, high accuracy as a target, studies the thermal characteristics and dynamic performances of the motorized spindle in FEM based on the software ANSYS. Specific details of the paper are as follows:
(1) The structure of the high speed motorized spindle is analyzed, the main components like the spindle motor, the spindle bearing, the lubricating system and the oil-water heat exchange cooling system on the stator of the motor are studied, besides, a key parameters, the interference depth between motor rotor and the shaft, needed at the stage of designing are analyzed and calculated.
(2) The heat transfer mechanism is analyzed; the heat source and the heat transfer coefficient of every part are calculated according to the actual working condition. On this basis, the thermal-structure coupling analyses of the motorized spindle unit studied in the thesis are done by the FEA software ANSYS, the temperature field, the temperature rises of the bearings and the thermal deformation in the front end of the motorized spindle are calculated, and the reasonable and effective measure is suggested.
(3) The structure form, the forcing and dynamic characteristic of the peculiar bearing form of Si_3N_44 Angular-contact ball bearings adopted in the motorized spindle unit on the high speed condition are analyzed, and the stiffness is also calculated. On this basis, the dynamic characteristics of the motorized spindle is analyzed, and the effect on the natural frequency by the pre-tightening force is also supplied by the experiment, which provides the necessary theory basis for optimizing the structure and improving dynamic behaviors of the motorized spindle, also establishes a basis for the research and application about the high speed spindle.
电主轴单元的结构设计、热态特性和动态特性在很大程度上决定了高速数控机床的加工质量和切削能力,也是影响其加工精度的重要因素。对主轴单元进行热态特性和动态特性的研究,对进一步提高高速机床的工作性能有十分重要的意义。
本文以高速磨削类加工数控机床用电主轴为研究对象,以实现电主轴的高速、高精度为目标,采用有限元方法,运用ANSYS软件,对电主轴的热态特性和动态特性进行研究,具体工作如下:
(1)分析了电主轴的结构特点,对主轴电机、主轴轴承、轴承润滑系统、电机定子的油一水热交换系统等关键部件进行了研究;并针对电主轴结构中的一个重要设计参数——电机与主轴的过盈量配合进行了分析计算。
(2)分析了电主轴的传热机制,根据实际工况对电主轴工作时的热源及各部分的传热系数进行了计算,在此基础上,利用大型有限元软件ANSYS对本课题中所研究的主轴单元进行了热一结构耦合分析,研究了电主轴单元的温度场分布、主轴轴承的温升情况及主轴前端的热变形情况,并提出了抑制主轴温升的合理有效的措施。
(3)分析了电主轴单元中所采用的特殊轴承形式——角接触混合陶瓷球轴承的结构形式及高速运转下的受力及动态特性,对其刚度进行了计算,在此基础上对电主轴进行了动力学分析,并通过实验说明了轴承的预紧力对主轴单元固有频率的影响情况,为优化主轴结构和改善电主轴的动态特性提供必要的理论依据,为高速电主轴的研究开发和应用奠定了基础。
High speed cutting and high speed machining taking high cutting speed, high feed speed and high machining precision as main characters is one of advanced manufacturing technology nowadays. High speed NC machine tool with high speed and high precision is the key factor to realize the high speed machining. High speed spindle is the core component of a high-performance machine tool. With the fact that the promptness developing and. being perfected of the electric drive technology, systematic machinery of the high speed NC machine tool' main drive structure has already got extremely simplification, has canceled wheel drive and the gear drive mainly. The motorized spindle of machine tool is direct drove by a built-in motor, thereby; the main transmission chain length of machine tool has been shortened for zero, and realized "zero transmission" of machine tool. That the drive structure form of the motorized spindle and motor "two combined into one" makes the motorized spindle component be independent relatively from the transmission system and the whole structure of the machine tool, be made as "the motorized spindle unit", the popular name "the motorized spindle" therefore.
To a great extent, the construction design, the thermal characteristics and dynamic performances of the motorized spindle determine machining qualities and cutting capabilities, and are the important factors influencing the precision of the high speed NC machine tool. It is important to study the thermal characteristics and dynamic performances of the motorized spindle on improving the performance of the high speed machine tool.
This paper takes the motorized spindle used in a high speed grinding machine tool as the study object, realizing high speed, high accuracy as a target, studies the thermal characteristics and dynamic performances of the motorized spindle in FEM based on the software ANSYS. Specific details of the paper are as follows:
(1) The structure of the high speed motorized spindle is analyzed, the main components like the spindle motor, the spindle bearing, the lubricating system and the oil-water heat exchange cooling system on the stator of the motor are studied, besides, a key parameters, the interference depth between motor rotor and the shaft, needed at the stage of designing are analyzed and calculated.
(2) The heat transfer mechanism is analyzed; the heat source and the heat transfer coefficient of every part are calculated according to the actual working condition. On this basis, the thermal-structure coupling analyses of the motorized spindle unit studied in the thesis are done by the FEA software ANSYS, the temperature field, the temperature rises of the bearings and the thermal deformation in the front end of the motorized spindle are calculated, and the reasonable and effective measure is suggested.
(3) The structure form, the forcing and dynamic characteristic of the peculiar bearing form of Si_3N_44 Angular-contact ball bearings adopted in the motorized spindle unit on the high speed condition are analyzed, and the stiffness is also calculated. On this basis, the dynamic characteristics of the motorized spindle is analyzed, and the effect on the natural frequency by the pre-tightening force is also supplied by the experiment, which provides the necessary theory basis for optimizing the structure and improving dynamic behaviors of the motorized spindle, also establishes a basis for the research and application about the high speed spindle.
引文
[1]张伯霖,杨庆东,陈长年.高速切削技术及应用[M].北京:机械工业出版社,2002
[2]吴玉厚.数控机床电主轴单元技术[M].北京:机械工业出版社,2006
[3]Hirotoshi Aramaki,Yoshio shoda,Yuka Morishita etc.The Performance of Ball Bearings with Silicon Nitride Ceramic Balls in High Speed Spindles for Machine Tools[J].Journal of Tribology.1998,10(110):693-698
[4]Jin Kyung Choi,Dai Gil Lee.Thermal Characteristic of the Spindle Bearing System with a Gear Located on the Bearing Span[J].International Journal of Machine Tools & Manufacture.1998,(38):1017-1030
[5]Berd Bossmanns,Jay F.Tu.A Thermal Model for High Speed Motorized Spindles[J].International Journal of MachineTools&Manufacture.1999,(39):1345-1366
[6]F.Farcas,M.D.Gafitnu.Some Influence Parameters on Greases Lubricated Rolling Contacts Service Life[J].Wear.1999,(225):1004-1010
[7]Berd Bossmanns,Jay F.Tu.A Power Flow Model for High Speed Motorized Spindles-Heat Generation Characterization[J].ASME Journal of Manufacturing Science and Engineering.2001,(123):494-505
[8]V.P.Raja,P.R.Pillai.Thermal Analysis of Spindle Units under High Speed Machining[J].IE(1)Journal-MC.2001,(81):155-159
[9]S.H.Yeo,K.Ramesh,Z.W.Zhong.Ultra-high-speed Grinding Spindle Characteristics upon Using Oil/air Mist lubrication[J].International Journal of Machine Tools&Manufacture.2002,(42):815-823
[10]Chi-Wei lin,Jay ETu,Joe Kamman.An Integrated Thermo-mechanical dynamic Model to Characterize Motorized Machine Tool Spindles during very High Speed Rotation[J].International Journal of Machine Tools&Manufacture.2003,(43):1035-1050
[11]杨启威.轴承系统温度场分析[J].轴承,1997(3):2-6
[12]Jenq-Shyong chen,Wei-Yao Hsu.Characterization and Modles for the Thermal Growth of a Motorized High Speed Spindle[J].International Journal of Machine Tools&Manufacture.2003,(43):1163-1170
[13]蒋兴奇,马家驹,赵联春.高速精密角接触球轴承热分析[J].轴承,2000(8):1-4
[14]Zhang Bolin,Ma Ping,Xiao Shuhong etc.Zero Transmission and its Application in High Speed CNC Machine Tools[J].Chinese Journal of Mechanical Engineering.2000(13).
[15]王勖成.有限单元法[M].北京:清华大学出版社,2003
[16]王焕定,吴德伦,林家骥.有限单元法及计算程序[M].中国建筑工业出版社,2002
[17]凌道盛,徐兴.非线性有限元及程序[M].浙江大学出版社,2004
[18]Spur G.主轴-轴承系统的计算:利用结构修正法确定静态和动态性能[J].国外轴承,1991(4):23-24
[19]G.D,Hagiuetal.Dynamic Characteristics of High Speed Angular Contact Ball Bearings[J].Wear.1997,211(1):22-29
[20]Bert R,Jorgensen,Yung C.Shin.Dynamics of Machine Tool Spindle/Bearing Systems under Thermal Growth[J].Journal of Tribology.1997,119(10):875-882
[21]Mohammed.A.Alfares,Abdallah.A.Esharkawy.Effects of Axial Preloading of Angular Contact Ball Bearings on the Dynamics of a Grinding Machine Spindle System[J].Journal of Materials Processing Technology.2003(136):48-59
[22]B.W.Huang,H.K.Kung.Variations of Instability in a Rotating Spindle System with Various Bearings[J].International Journal of Mechanical Sciences.2003(45):57-72
[23]Chiwei Lin,Jay F.Tu,Joe Kamman.An Integrated Thermal-mechanical-dynamic Model to Characterize Motorized Machine Tool Spindles during very High Speed Rotation[J].International Journal of Machine Tools&Manufacture.2003(43):1035-1050
[24]Jenq-Shyong Chen,Kwan-Wen Chen.Bearing Load Analysis and Control of a Motorized High Speed Spindle[J].International Journal of Machine Tools&Manufacture.2005:1487-1493
[25]肖曙红.前支承为三联角接触球轴承的主轴组件的性能分析和简化计算:[硕士学位论文].大连:大连理工大学,1994
[26]黄旭东,费仁元,杨家华.主轴部件动态特性的实验研究[J].北京工业大学学报,1994,20(3):33-38
[27]朱江红.不同预载下的球轴承变形的程序设计[J].导弹与航天运载技术,1995(4):28-40
[28]许敏,赵冬初,肖祖光,查全.电主轴用高速角接触陶瓷球轴承的开发[J].机械设计与研究,1997(3):31-33
[29]刘素华.加工中心用电主轴的研究与设计:[硕士学位论文].北京:北京理 工大学.2000
[30]蒋兴奇.主轴轴承热特性及对速度和动力学性能影响的研究:[博士学位论文].杭州:浙江大学,2001
[31]何晓亮,熊万里,黄红武。高速精密主轴轴承热特性的计算及分析[J].机械,2003(6):14-16
[32]刘素华,冯利民.电主轴单元的动静态特性分析[J].河北冶金,2003(4):25-27
[33]朱金虎,翁世修,蒋书运.高频电主轴临界转速计算及其影响参数分析[J].机械设计与研究,28-30
[34]蒋书运.高速电主轴动态设计方法[J].世界制造技术与装备市场,2004(5):54-56
[35]王硕桂,严红日.高速电主轴端部跳动对电主轴横向振动的影响[J].中国科学技术大学.2004(5):38-39
[36]Yanzhong Xu,Shuyu Jiang.Dynamic Characteristics of High Speed Augular Contact Ceramic Ball Bearing[J].Southeast Universi Journal of Southeast University(English Edition).2004
[37]徐浩,许颖.高速机床主轴用陶瓷球轴承动态性能试验分析[J].轴承.2005(2):28-29
[38]鲍里先科,丹科,亚科夫列夫.电机中的空气动力学与热传递[M].北京:机械工业出版社,1985
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[2]吴玉厚.数控机床电主轴单元技术[M].北京:机械工业出版社,2006
[3]Hirotoshi Aramaki,Yoshio shoda,Yuka Morishita etc.The Performance of Ball Bearings with Silicon Nitride Ceramic Balls in High Speed Spindles for Machine Tools[J].Journal of Tribology.1998,10(110):693-698
[4]Jin Kyung Choi,Dai Gil Lee.Thermal Characteristic of the Spindle Bearing System with a Gear Located on the Bearing Span[J].International Journal of Machine Tools & Manufacture.1998,(38):1017-1030
[5]Berd Bossmanns,Jay F.Tu.A Thermal Model for High Speed Motorized Spindles[J].International Journal of MachineTools&Manufacture.1999,(39):1345-1366
[6]F.Farcas,M.D.Gafitnu.Some Influence Parameters on Greases Lubricated Rolling Contacts Service Life[J].Wear.1999,(225):1004-1010
[7]Berd Bossmanns,Jay F.Tu.A Power Flow Model for High Speed Motorized Spindles-Heat Generation Characterization[J].ASME Journal of Manufacturing Science and Engineering.2001,(123):494-505
[8]V.P.Raja,P.R.Pillai.Thermal Analysis of Spindle Units under High Speed Machining[J].IE(1)Journal-MC.2001,(81):155-159
[9]S.H.Yeo,K.Ramesh,Z.W.Zhong.Ultra-high-speed Grinding Spindle Characteristics upon Using Oil/air Mist lubrication[J].International Journal of Machine Tools&Manufacture.2002,(42):815-823
[10]Chi-Wei lin,Jay ETu,Joe Kamman.An Integrated Thermo-mechanical dynamic Model to Characterize Motorized Machine Tool Spindles during very High Speed Rotation[J].International Journal of Machine Tools&Manufacture.2003,(43):1035-1050
[11]杨启威.轴承系统温度场分析[J].轴承,1997(3):2-6
[12]Jenq-Shyong chen,Wei-Yao Hsu.Characterization and Modles for the Thermal Growth of a Motorized High Speed Spindle[J].International Journal of Machine Tools&Manufacture.2003,(43):1163-1170
[13]蒋兴奇,马家驹,赵联春.高速精密角接触球轴承热分析[J].轴承,2000(8):1-4
[14]Zhang Bolin,Ma Ping,Xiao Shuhong etc.Zero Transmission and its Application in High Speed CNC Machine Tools[J].Chinese Journal of Mechanical Engineering.2000(13).
[15]王勖成.有限单元法[M].北京:清华大学出版社,2003
[16]王焕定,吴德伦,林家骥.有限单元法及计算程序[M].中国建筑工业出版社,2002
[17]凌道盛,徐兴.非线性有限元及程序[M].浙江大学出版社,2004
[18]Spur G.主轴-轴承系统的计算:利用结构修正法确定静态和动态性能[J].国外轴承,1991(4):23-24
[19]G.D,Hagiuetal.Dynamic Characteristics of High Speed Angular Contact Ball Bearings[J].Wear.1997,211(1):22-29
[20]Bert R,Jorgensen,Yung C.Shin.Dynamics of Machine Tool Spindle/Bearing Systems under Thermal Growth[J].Journal of Tribology.1997,119(10):875-882
[21]Mohammed.A.Alfares,Abdallah.A.Esharkawy.Effects of Axial Preloading of Angular Contact Ball Bearings on the Dynamics of a Grinding Machine Spindle System[J].Journal of Materials Processing Technology.2003(136):48-59
[22]B.W.Huang,H.K.Kung.Variations of Instability in a Rotating Spindle System with Various Bearings[J].International Journal of Mechanical Sciences.2003(45):57-72
[23]Chiwei Lin,Jay F.Tu,Joe Kamman.An Integrated Thermal-mechanical-dynamic Model to Characterize Motorized Machine Tool Spindles during very High Speed Rotation[J].International Journal of Machine Tools&Manufacture.2003(43):1035-1050
[24]Jenq-Shyong Chen,Kwan-Wen Chen.Bearing Load Analysis and Control of a Motorized High Speed Spindle[J].International Journal of Machine Tools&Manufacture.2005:1487-1493
[25]肖曙红.前支承为三联角接触球轴承的主轴组件的性能分析和简化计算:[硕士学位论文].大连:大连理工大学,1994
[26]黄旭东,费仁元,杨家华.主轴部件动态特性的实验研究[J].北京工业大学学报,1994,20(3):33-38
[27]朱江红.不同预载下的球轴承变形的程序设计[J].导弹与航天运载技术,1995(4):28-40
[28]许敏,赵冬初,肖祖光,查全.电主轴用高速角接触陶瓷球轴承的开发[J].机械设计与研究,1997(3):31-33
[29]刘素华.加工中心用电主轴的研究与设计:[硕士学位论文].北京:北京理 工大学.2000
[30]蒋兴奇.主轴轴承热特性及对速度和动力学性能影响的研究:[博士学位论文].杭州:浙江大学,2001
[31]何晓亮,熊万里,黄红武。高速精密主轴轴承热特性的计算及分析[J].机械,2003(6):14-16
[32]刘素华,冯利民.电主轴单元的动静态特性分析[J].河北冶金,2003(4):25-27
[33]朱金虎,翁世修,蒋书运.高频电主轴临界转速计算及其影响参数分析[J].机械设计与研究,28-30
[34]蒋书运.高速电主轴动态设计方法[J].世界制造技术与装备市场,2004(5):54-56
[35]王硕桂,严红日.高速电主轴端部跳动对电主轴横向振动的影响[J].中国科学技术大学.2004(5):38-39
[36]Yanzhong Xu,Shuyu Jiang.Dynamic Characteristics of High Speed Augular Contact Ceramic Ball Bearing[J].Southeast Universi Journal of Southeast University(English Edition).2004
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