共查询到19条相似文献,搜索用时 109 毫秒
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设计一种用于支承电机转子的超声波悬浮轴承,该轴承由圆锥形压电换能器辐射端面与连接在电机转子端的圆锥环构成。压电换能器在振动过程中在轴承间隙形成稳定的承载气膜,对电机转子悬浮。对承载气膜产生的承载能力进行分析和测试,获得悬浮力与悬浮间隙之间的关系,从理论上分析在超声悬浮支承条件下,悬浮间隙变化与气膜刚度对电机转速的影响,对转子最高转速与悬浮间隙的关系进行实验研究。结果表明,利用压电换能器圆锥辐射面与圆锥环构造的超声波悬浮轴承,能够形成对电机转子的轴向和径向支承;通过减小悬浮间隙,能够增强间隙气膜的刚度,并提高转子的最高转速,轴承间无摩擦。 相似文献
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复合材料储能飞轮挠性结构振动的磁轴承控制 总被引:1,自引:0,他引:1
储能密度是储能飞轮的重要指标之一,选用碳纤维、玻璃纤维复合材料的储能飞轮可以有效提高储能密度,同时,选用磁悬浮支承则可以适应真空环境及减少损耗。但是,由此也增加了结构的复杂性,例如,连结飞轮转子中金属部件与复合材料之间的挠性薄壳轮毂具有不同于常规刚体飞轮的动力学模型特性。针对薄壳结构的模态振动特征与陀螺效应控制之间的矛盾,描述一种具有挠性结构储能飞轮的磁轴承控制方法。在模态分析的基础上,利用多通道添加相位整形的控制方法有效抑制了系统中的挠性结构的模态振动。试验结果表明,使用所设计的控制器,转子可平稳通过中心频率为340 Hz的轮毂——心轴挠性模态振动区域,运行转速475 Hz(28 500 r/min),轮缘最大线速度达到450 m/s,并成功实现飞轮的充放电过程。 相似文献
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旋转机械的工作转速在其临界转速分布范围内会产生剧烈振动,严重时会使系统遭到破坏,因此研究临界转速的影响因素至关重要。建立柔性支撑的储能飞轮转子有限元模型,基于ANSYS Workbench分析软件对不同支撑刚度条件下转子的临界转速进行计算和分析。通过计算结果分析支撑刚度对转子的前三阶临界转速的影响,为使系统的临界转速偏离工作转速提供设计和调整依据。 相似文献
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提出了一种基于超声悬浮和驱动的非接触式压电作动器,该作动器中的转子呈完全悬浮状态。转子的悬浮由兰杰文换能器提供,自身旋转与定位由圆筒型定子提供。通过分别对换能器和定子的压电陶瓷片施加电压,使得换能器悬浮端面激发出一阶弯曲振动模态,而定子激发出两相B(0,3)驻波并合成一高声强行波,进而诱发高声强声场来驱动转子。分别建立了非接触式压电作动器中兰杰文换能器和定子的有限元模型,对换能器和定子进行了分析、设计、扫频以及定频试验,确定了结构方案,
最后加工、制造了样机。搭建了整个样机的测试系统,对其悬浮和驱动特性进行了分析,测得转子转速可达4261r/min。结果表明转子在近声场的作用下成功地实现了完全悬浮式的高速旋转。
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Taijiang Peng Zhigang Yang Junwu Kan Fengjun Tian Xiaohong Che 《Frontiers of Mechanical Engineering in China》2009,4(4):415-419
The bearing is an important basic mechanical part for supporting a shaft. A flywheel storage system needs a type of noncontact
support bearing to enhance the speed of the axis. A magnetic suspension bearing is one type of noncontact bearing but has
electromagnetic interference to other electric equipment. Based on the performance research of ultrasonic levitation technology,
a novel noncontact bearing called ultrasonic bearing is presented, which consists of a special piezoelectric vibrator supporting
the load. Experiments are carried out to study the relationships among the amplitude of the vibrator and levitation clearance,
the highest speed of the axis, and the frictional moment of the axis. Results show that the levitation clearance becomes smaller
gradually with increasing load; the rotation speed is up to 8946 r/min, and the friction moment is only 2.095×10−5 N · m when the levitation clearance is 8.53 μm. The ultrasonic bearing is highlighted because of its simple structure, strong
levitation ability, and low friction moment. 相似文献
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Taijiang PENG Zhigang YANG Junwu KAN Fengjun TIAN Xiaohong CHE 《Frontiers of Mechanical Engineering》2009,4(4):415
The bearing is an important basic mechanical part for supporting a shaft. A flywheel storage system needs a type of noncontact support bearing to enhance the speed of the axis. A magnetic suspension bearing is one type of noncontact bearing but has electromagnetic interference to other electric equipment. Based on the performance research of ultrasonic levitation technology, a novel noncontact bearing called ultrasonic bearing is presented, which consists of a special piezoelectric vibrator supporting the load. Experiments are carried out to study the relationships among the amplitude of the vibrator and levitation clearance, the highest speed of the axis, and the frictional moment of the axis. Results show that the levitation clearance becomes smaller gradually with increasing load; the rotation speed is up to 8946 r/min, and the friction moment is only 2.095×10−5 N·m when the levitation clearance is 8.53 μm. The ultrasonic bearing is highlighted because of its simple structure, strong levitation ability, and low friction moment. 相似文献
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考虑摩擦因数与滑动速度相关时的轮轨滚动接触有限元分析 总被引:1,自引:0,他引:1
使用与滑动速度相关的摩擦因数替代库伦摩擦定律中的常系数,结合mixed Lagrangian/Eulerian方法建立轮轨滚动接触有限元模型,分析牵引力主导的蠕滑工况下的干燥状态的轮轨滚动接触特性。通过与摩擦因数取值为常数的轮轨滚动接触分析结果对比发现:与滑动速度相关的摩擦因数对轮轨滚动接触最大接触应力和接触斑面积影响不大,均在1%以内;但是对轮轨接触斑内最大Mises应力、最大纵向切应力、最大横向切应力和最大等效塑性应变影响较大,特别是对最大纵向切应力影响幅度近20%;更需要引起注意的是对轮轨滚动接触摩擦力矢量分布和切向塑性应变分布影响明显,这对轮轨滚动接触疲劳损伤分析非常重要。 相似文献
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以碳/铜载流摩擦副为研究对象,在CETR UMT-2多功能摩擦磨损试验机上,采用环/块接触方式,对载流摩擦过程中摩擦因数的影响因素进行了试验研究。结果表明:在低速条件下,载流稳态摩擦因数随法向载荷和电流的增大而增大,高速时结果相反;无电流时稳态摩擦因数随转速升高而增大,载流时则随转速升高呈先增大后减小的趋势;载流时摩擦因数开始一般都比无电流时摩擦因数小,随后逐渐增大,并超过无电流时的摩擦因数,所需时间随转速和法向载荷的增大而缩短;低速载流摩擦因数变化的关键因素可能是摩擦过程中产生的摩擦热,高速载流摩擦因素的变化则可能与微电弧对材料的烧蚀机制密切相关。 相似文献
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The accurate estimation of road friction coefficient in the active safety control system has become increasingly prominent. Most previous studies on road friction estimation have only used vehicle longitudinal or lateral dynamics and often ignored the load transfer, which tends to cause inaccurate of the actual road friction coefficient. A novel method considering load transfer of front and rear axles is proposed to estimate road friction coefficient based on braking dynamic model of two-wheeled vehicle. Sliding mode control technique is used to build the ideal braking torque controller, which control target is to control the actual wheel slip ratio of front and rear wheels tracking the ideal wheel slip ratio. In order to eliminate the chattering problem of the sliding mode controller, integral switching surface is used to design the sliding mode surface. A second order linear extended state observer is designed to observe road friction coefficient based on wheel speed and braking torque of front and rear wheels.The proposed road friction coefficient estimation schemes are evaluated by simulation in ADAMS/Car. The results show that the estimated values can well agree with the actual values in different road conditions. The observer can estimate road friction coefficient exactly in real-time andresist external disturbance. The proposed research provides a novel method to estimate road friction coefficient with strong robustness and more accurate. 相似文献
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水润滑条件下转速对车轮钢滚动接触疲劳和磨损性能的影响 总被引:1,自引:0,他引:1
为探究水润滑条件下转速对车轮钢滚动接触疲劳和磨损性能的影响,利用滚动接触摩擦磨损试验测试不同转速下车轮试样的剥离寿命、摩擦因数和磨损率,并结合磨损形貌和裂纹扩展形貌观察,对比分析不同转速下摩擦磨损和剥离寿命的影响因素。结果表明:随转速提高,车轮材料氧化程度加剧,导致摩擦因数逐渐增加;当转速由250 r/min增至500 r/min时,摩擦因数增幅较小,应变速率增加导致磨损率下降,当转速由500 r/min增至1000 r/min时,摩擦因数急剧增加,导致材料磨损率增加;随转速提高,剖面塑性流动层厚度、裂纹扩展角度、裂纹分叉深度和最大扩展深度均呈现减小趋势。转速增加带来的摩擦因数的增加,一方面缩短裂纹萌生寿命,另一方面减小了裂纹发生向上转折的深度,最终导致滚动接触疲劳寿命随转速的增加而减小。 相似文献
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针对风轮机输出特性模拟系统展开了的软硬件设计及应用.采用VC++编程提供人机交互界面,输入风速时变数据,会得到理想的风轮机的转速、功率、转矩曲线.利用交流异步电机变频调速系统,模拟现场风况并带动风轮的转动,建立起一个模拟实验平台,提供了在实验室内进行变速恒频等风力发电技术研究工作的条件.应用所设计的风舱输出特性模拟系统,拖动30kW的风力发电机进行实验,从而验证了变频调速异步电机模拟风轮输出特性的方案的可行性与实用性. 相似文献