【作者】 王宝金；

【导师】 王厚立；

【作者基本信息】 南京林业大学 ， 机械设计及理论， 2004， 博士

【摘要】 磨盘实际间隙是指动磨片和定磨片在研磨区内齿表面之间的距离。磨盘间隙对纤维分离质量影响很大，热磨过程中应选择合适的磨盘间隙并保持恒定，以保证纤维浆料的质量和产量。通常磨盘间隙控制在0.2～0.5mm之间，要求控制精度达到0.01mm．但初始调整的磨盘间隙会随着磨片的磨损而加大，在运行过程中磨盘实际间隙的精确测量与显示，迄今仍是一个世界级的难题。 热磨机主轴运行状态既影响热磨机的正常运行又影响到纤维分离的质量。 本文采用理论和实验研究相结合的方法，对磨盘实际间隙的精确测量和主轴运行状态的监测方法进行了探索研究，填补了国内这方面的研究空白。 论文提出了磨盘间隙接触式测量法和非接触式测量法的概念。接触式测量法不能实时反映磨片磨损对磨盘间隙的影响。在热磨机的实际结构和运行条件下，要实时对磨盘间隙进行精确测量，只能采用非接触式测量法。 首次提出了采用电容式位移传感器和电涡流式位移传感器两种测量磨盘实际间隙的方案，用于测量动磨片的轴向位移和磨片磨损后的磨盘实际间隙。 初步设计了用于测量磨盘实际间隙的电容式位移传感器，它具有能随定磨片一起同步磨损、传感器获取的信号直接反映磨盘间隙、结构简单、所需的量程小等优点。 电涡流式位移传感器测量磨盘实际间隙的方案，由一只电涡流式位移传感器和一只超声波测厚仪组合而成，利用电涡流传感器测量动磨片的轴向位移和磨损后的齿面位置，超声波传感器测量定磨片磨损后的厚度，然后将两只传感器的测量数据结合传感器的安装尺寸，通过数学运算得到磨盘实际间隙。对电涡流传感器的探头需要采取保护措施。由于电涡流传感器和超声波测厚仪都可以购买到定型产品，方案实施相对容易。 论文对电涡流式位移传感器测量磨盘实际间隙方案进行了进一步的静态和动态试验研究。静态试验研究表明：木材的含水率能引起电涡流传感器的输出电压下降，但下降的幅度甚微；不同品种的植物纤维原料对传感器输出电压的影响很小；介质温度的上升也能引起传感器输出电压下降，因此应选用高温型的传感器加以解决；介质中含有铁屑时，传感器输出电压值升高，且随铁屑含量的增加而增大，但热磨机研磨的纤维中金属磨屑含量非常小，对电涡流传感器的输出电压几乎没有影响；随着被测金属板对传感器探头覆盖面积的变化会引起输出电压的变化，覆盖面积增大，传感器输出电压逐渐减小。动态试验研究表明：电涡流传感器、位移变送器、数据采集卡和计算机组成的测量采集系统，采集信号波形区分明显，能够实现高速动态的测试。因此，电涡流传感器能用于测量动磨片的轴向位移和磨损后的齿面位置。采用电涡流式位移传感器和超声波测厚仪组合测量磨盘实际间隙的方案是可行的。但对电涡流传感器保护罩的材料选择需要进一步的试验研究。 通过自行设计和制造的热磨机主轴系统试验装置，首次进行了主轴运行状态监测方法的模型实验研究。在轴承组的轴承套和轴承套座上多个不同位置进行布点测试。实验研究表明:将传感器直接安装在轴承套上，所获取的轴承的振动信号强度较大;而将传感器安装在轴承套座上，由于信号传递途径的中间界面多，所获取的轴承的振动信号强度较弱;在水平方向信号衰减较小，信号的加速度有效值比轴承套上的测点下降了约20%。而垂直方向信号衰减比较大，原因是垂直方向的间隙较大。尽管在水平方向信号强度有所下降，但振动信号的主振频率没有改变，依然能够反映出轴承振动的状况。 对热磨机进行主轴运行状态监测时，可以将传感器安装在轴承套座上径向的水平位置，并且在轴向应尽量靠近研磨时轴承所在的位置。关键词:热磨机磨盘实际间隙非接触测量主轴运行状态监测更多还原

【Abstract】 Real plate gap means the clearance between the surface of stationary disc and the surface of rotating disc in refining zone. The quality of fiber separating is deeply affected by plate gap. In order to guarantee constant and uniform fiber quality and output of the refiner, the proper plate gap should be chosen and kept in constant at all times while the refine is in operation. Generally plate gap should be controlled in the range of 0.2~0.5mm and the dimensional precision in operation should be defined at 0.01mm. As a matter of fact that plate gap adjusted at start-up will increase as the plates wear down., There is still a difficult problem in the worldwide to measure and indicate real plate gap. when refiner is runningThe running state of main spindle of refiner not only affects refiner running in good condition but also affects the fiber quality.The thesis researched the technologies of measuring accurately the plate gap and monitoring the running state of main spindle of refiner with the approach combining theoretical analyzing and experimental tests. The technologies supplied a gap in the domestic research area.The thesis puts forward the concepts of contact plate gap measurement and non-contact plat gap measurement. Contact plate gap measurement cannot timely indicate the change of plate gap caused by plate wear. Under the structure and running condition of refiner, to measure plate gap accurately in time, non-contact plat gap measurement must be used.For the first time, the thesis brings forward two plans of measuring real plate gap by using capacitive displacement sensor and eddy current displacement sensor respectively, in order to measure displacement of and surface position after wear of rotating disc.A special capacitive displacement sensor, which was designed for measuring plate gap, has some advantages such as: be able to wear down with plate wearing down, the output of sensor directly reflecting the real plate gap, simple structure, small measuring range.By using eddy current displacement sensor, the gap-measuring plan consists of one eddy current displacement sensor and one ultrasonic thickness sensor. Eddy current sensor measures displacement and surface position after wear of rotating disc, and ultrasonic sensor measures thickness after wear of stationary disc. As a result, the real plate gap will be calculated by using three parameters: the displacement of rotating disc, thickness of stationary disc, and position of eddy current sensor. The probe of eddy current sensor needs a safeguard cover. Since eddy current displacement sensor and ultrasonic thickness sensor can be purchased easily, so the plan can be put in practice easily.Static and dynamic experimental tests were carried out to the plan that is to measure real plate gap by using eddy current displacement sensor.Static experimental test shows that wet wood can make tiny decline to the output voltage of eddy current sensor. As for different species woods, their influences on output voltage of eddy current sensor are almost same. Hot wood can also cause the output voltage to decline; so high-temperature sensor should be selected. When medium contains ferrous powder, the output of sensor arises, the higher ferrous powder content is, the more output is. The fiber produced by refiner, which contains little ferrous powder, does not influence on the output of sensor. The area of probe overlaid by mental panel affects the output of sensor. The more the area is, the smaller the output is.Dynamic experimental test shows that the measure and collection system, which consists of eddy current sensor and displacement converter and data collector and computer, could be used for high frequency dynamic measurement. So eddy current sensor could be used for measuring displacement and surface position after wear of rotating disc. As a result, it is a feasible plan to combine one eddy current displacement sensor with one ultrasonic thickness sensor to measure real plate gap. At the same time, to select a proper kind of material used for safeguard cover of eddy c更多还原