查询词典 ball

The effect of tribology factors on bearing vibration is studied experimentally. AR model and WPT are used to processing the normal arid abnormal signals. The results are as follows:1. The vibration of ball bearings is caused by the tribology action of contact pairs of ball and ring races and has the essential of tribo-dynamics. Any factors affecting the tribology characteristics of contact pairs will affect vibration and noise of bearings consequently.2. Vibration characteristics of bearing keep almostly unchanged with the increasing of axial load expecting the increasing of nature frequencies. When radial load increasing with axial load unchanged, nature frequencies keep unchanged but some new vibration peaks appears in the spectrum.3. Vibration amplitudes are damped and nature frequency are enhanced with sufficient lubrication. Vibration and noise of bearings increase obviously and roar can happen and the contact surfaces scratch slightly under insufficient and unclean lubrication state. Bearing will be disabled in a few minutes without any lubrication.4. Bearing vibration is unstable under low speed. With the speed increasing, the vibration become stable and natural frequencies increase slightly but the amplitudes increase apparently.5. Bearing vibration can be excited only by some harmonics ofwaviness without lubrication and by all harmonics with lubrication based on the theoretical analysis.6. The nature frequencies of ball bearings decrease with the increasing sizes. When international clearance increasing, nature frequencies decrease in radial and increase in axial and angular and the amplitudes increase in radial and decrease in axial and angular. When the number of balls increasing, nature frequencies increase and amplitudes decrease. When the pitch diameter increasing, axial nature frequency increase and others nearly keep no change. When outer race groove curvature radius increasing, nature frequencies increase in radial and decrease in axial and angular and amplitudes keep no change in radial and increase in axial and angular. When inner race groove curvature radius increasing, nature frequencies decrease and amplitudes increase.7. The distortion in amplitude and frequency components of bearing vibration signals picked up by the present probe measurement method is founded and right conclusions cannot be achieved by the signals. When accelerometer is rigidly screwed with steel stud onto a flat outer surface of a ball bearing, vibration signal can be got without distortion and the reliability of research on bearing vibration is assured.8. AR model is suitable for large samples of bearing vibration signals, square root of length of samples can be used as the upper limitation of order determination and the FPE order selection criterion is effective. Many advantages of AR spectrum are founded over the classical based on FFT.9. Time-Frequency analysis is necessary for abnormal noise of ball bearings. WPT overcomes the principle shortcomings of STFT and proved to be a best tool to process the abnormal signals.

理论分析和试验研究表明： 1球轴承振动是钢球—滚道接触副中的各种摩擦学作用引起的，具有摩擦动力学的本质，任何对接触副的摩擦学特性有影响的因素都将对球轴承的振动和噪声特性产生影响； 2中心轴向载荷作用下，载荷增大使球轴承的固有振动频率升高，载荷越大同样的载荷增幅引起的频率升幅减小，足够大的中心轴向载荷作用下载荷的变化对球轴承振动的频率特性不会产生明显的影响； 3轴向和径向联合载荷作用下，径向载荷不大时球轴承振动的固有频率基本不变，但是可能引起变刚度激励的非线性振动，出现新的频峰，过大的径向载荷将使部分钢球脱离接触，使球轴承的振动和噪声呈现不稳定状态； 4润滑对球轴承的振动和噪声特性有重要的影响，良好的润滑对振动有明显的抑制作用，润滑不充分时，振动和噪声的水平会有明显增高，一定条件下还会激发接触副中的谐振，发出啸声，造成接触表面的伤害，无润滑干接触时，短时的运转就会损伤接触副表面，使振动和噪声迅速增大，并随时可能引发严重的磨损和卡滞失效；接触副润滑良好时，油膜的"刚化效应"使球轴承振动的固有频率有所提高，润滑剂中含有弥散性污浊时，振动的幅度总体升高，但弥散性污浊不会改变球轴承振动的频率特性；浙江大学博士学位论文：球轴承振动的研究 5低速时，球轴承振动的基本特征呈现不稳定状态，随着转速的提高，球轴承振动的频率特性趋于稳定，固有频率频峰升高； 6理论分析表明，干接触时钢球和滚道表面波纹度的某些谐波分量能激励球轴承的振动，振动的幅值与谐波幅值成正比，实际球轴承中钢球的分布不可能完全均匀，波纹度的激励作用会随时发生；润滑接触的分析表明，波纹度的任意谐波分量均能激励球轴承的振动； 7球轴承的几何和结构参数分析表明，球轴承尺寸越大，径向、轴向和角振动的固有频率越低；钢球中心圆直径增大，球轴承的径向和轴向振动的固有频率基本不变，角振动的固有频率有所上升，振动的幅频特性基本不变；径向游隙加大使球轴承的径向振动固有频率降低，轴向和角振动的固有频率有所升高，径向振动幅频特性的幅值升高，而轴向和角向降低；钢球的数量增多使球轴承振动的固有频率上升，幅频特性的幅值下降，径向振动的幅值下降最为明显；外圈沟曲率半径系数增大使球轴承径向振动的固有频率升高，轴向和角振动的固有频率降低，径向幅频特性基本不变，轴向和角向幅频特性幅值升高；内圈沟曲率半径系数增大使径向、轴向和角振动固有频率均下降，振动幅频特性的幅值均有升高； 8试验对比表明，传感器采用探针式安装时，由于探针接触副接触特性的影响，钡(量得到的球轴承振动信号有失真，采用专门设计和制作的试验球轴承，以固定式安装加速度计，首次测量得到了球轴承振动的真实信号，通过对振动信号的分析，验证了球轴承振动的理论模型； 9)基于时间序列分析的AR模型适用于大样本球轴承振动信号的分析，以样本长度的均方根值作定阶上界，FPE做判阶准则，给出的AR谱光滑，频率分辨率高，是球轴承振动分析的简便而可靠的手段； 10以时频域分析的小波包变换分析球轴承异音信号能够比较好地定位和聚焦异音发生的时间，时间间隔，频率范围，同样是球轴承振动分析的可靠的手段，可用作球轴承故障诊断技术。

This research presented a new guide mechanism and belt driving theory of the abrasive band polishing for inner aperture, satisfied the driving requirement of abrasive belt leading smoothly into grinding area, realized the band grinding and band polishing of inner aperture, developed a abrasive band polishing headstock for of the ball track of ball bearing and roller bearing individually adopting a way of curvature concave oscillating and vibrating, researched the process regular and fundamental process method and parameter of abrasive band polishing of ball track. The results of experiments and tests showed that the surface roughness of ball track by abrasive band polishing can reach Ra0.02μm, and the original geometric cross section shape precision of ball track can be kept.

本项研究提出了砂带研抛内孔的新型导引机构和传带原理，满足了砂带平稳导入内孔磨削区的传动要求，实现了内孔的砂带磨削和研抛；研制了采用弧面摆动和振动方式分别用于球轴承滚道和滚柱轴承滚道研抛的砂带研抛头架；研究了轴承滚道砂带研抛的工艺规律和基本工艺方法、工艺参数；实验测试结果，轴承滚道砂带研抛的表面粗糙度达Ra0.02μm，研抛过程保持了滚道的原始几何截面形状精度。

On the Zong say, can see, for the N ball but speech, because ball of successively different, the all leading of the ball of each number ball is different, and, after depending ball of all rate will one by one in order become big.

综上所述，可以看到，对于出N个号球而言，由于出球的先后不同，每个号球的出球的概率是不同的，而且，靠后出球的概率会依次变大。

Complicated tactic and technique combined training, move training, training for difficult techniques that are usually hard to grasped in one-on-one training, athlete's physical, mental and volitive capacity exercises, are implemented in the entire multi-ball teaching and training via the use of such 3 training means as "multi-point plus multi-ball","interactive multi-point plus multi-ball" and "single training with multi-ball", intensified training is carried out in an action specific way by means of ball supply, and the said problems are settled one by one.

教学设计理念是按照乒乓球技能形成的规律：泛化、分化、巩固、自动化4个阶段来设计多球训练方案，对乒乓球技能形成的各个阶段的学习、动作技能形成；对较复杂的技战术组合练习、步法及平时在对练中很难上手的难度技术；对运动员身体、心理、意志品质的锻炼等通过&多点多球&、&交互式多点多球&、&多球单练&3种训练手段，贯穿于整个多球教学与训练中，以供球的形式有针对性地进行强化训练并一一加以解决。

Complicated tactic and technique com-bined training, move training, training for difficult techniques that are usually hard to grasped in one-on-one train-ing, athlete's physical, mental and volitive capacity exercises, are implemented in the entire multi-ball teaching and training via the use of such 3 training means as "multi-point plus multi-ball","interactive multi-point plus multi-ball" and "single training with multi-ball", intensified training is carried out in an action specific way by means of ball supply, and the said problems are settled one by one.

摘 要：教学设计理念是按照乒乓球技能形成的规律：泛化、分化、巩固、自动化4个阶段来设计多球训练方案，对乒乓球技能形成的各个阶段的学习、动作技能形成；对较复杂的技战术组合练习、步法及平时在对练中很难上手的难度技术；对运动员身体、心理、意志品质的锻炼等通过&多点多球&、&交互式多点多球&、&多球单练&3种训练手段，贯穿于整个多球教学与训练中，以供球的形式有针对性地进行强化训练并一一加以解决。

Our factory specializes in the production and sale of stainless steel ball, hollow ball, Ball, micro-ball, punch ball, etc.; material as follows: stainless steel 302/304/304HC/316/316L/420/440, bearing steel, bronze, brass,.

本厂专业生产和销售不锈钢球、空心球、铜球、微型钢珠、打孔球等；材质为：不锈钢302/304/304HC/316/316L/420/440，轴承钢，青铜，黄铜，。

Has developed high-temperature hard seal ball valve, high pressure forged steel ball valve, double eccentric semi-ball valve, V-ball valve, full welded ball valve Buried, dedicated coal ball valve, as well as the American Standard valve, check valve, shut-off valves, filters, valves, flat gate valve series of high-tech products.

先后研制开发出高温硬密封球阀、高压锻钢球阀、双偏心半球阀、V型球阀、全焊接埋地式球阀、煤粉专用球阀，以及美标闸阀、止回阀、截止阀、过滤器、蝶阀、平板闸阀等一系列高新产品。

Chan Fa La indicated that she was a super fan of the Chinese women volley ball team and enjoyed watching volley ball games. But she doesn't know playing volley ball. She joked that she wanted to learn from the women volley ball players if there was a chance. She believed that she would be very busy at saving the ball .

法拉表示自己是女排的超级Fans，很喜欢欣赏排球比赛，可是她并不懂打排球，笑言如果有有机会跟女排，相信她只会忙著全场救球。

The effect of the friction moment of bearings on performance is researched. The forming mechanic and influence factors of the friction moment of ball bearing are analyzed. Suitable clearness and groove radius of ball bearings are obtained by experiment and calculation. The relationship between starting moment of ball bearing and various lubricants is analyzed. The measure for reducing the starting moment of ball bearing is put forward, it is the theory basis and reference for ball bearing design of small power unit system.The system is an unstable system when the 24-station ball pen tip production machine is running because of various interferences. It is too hard to describe the system by linear method, so the nonlinear formulation must be used.

研究了小动力头系统轴承摩擦力矩对运转性能的影响，分析了球轴承摩擦力矩的产生机理及影响因素，采用实验和计算的方法得到了动力头球轴承的合理间隙及球轴承沟曲率半径，分析了各种润滑剂与球轴承启动力矩的关系，并提出了减小轴承启动力矩的措施，为小动力头系统的轴承设计提供了理论依据及实践参考。24工位笔头加工机械在笔头的生产加工过程中，由于受到各种因素的干扰是一个不稳定系统，其稳定性会发生一定变化，而且很难用线性方法表述。

Until the end of the ball. Then, in the course side of a position in any election outside a ball point, headed into the first one issued to the floor after the ball, two balls can be kicked from a ball-point target header, if hit, two balls for the win, l for the header, back to the ball-point re-serve.

然后，在球场边外的任何一个位置选一个发球点，头球向场内发进第一个球以后，二球就可以从发球点瞄准头球踢打，如果打中，二球为赢，升为头球，退回到发球点重新发球。

It goes back to what I told you...

现在回到我告诉过你的。。。

With a supporter in Mr Charest and an admirer in Mr Dumont, Mr Harper may be encouraged to call an election himself.

由于在沙雷那边有个支持者，杜蒙那边有个崇拜者，鼓励哈珀为自己举行一次选举。