DEVELOPMENT OF HIGH SPEED LASER SCANNER MOTOR WITH VERY LOW NOISE LEVEL 0277033CA 80096718

本研究的目的是开发一种具有非常低噪声水平的小型激光扫描仪电机。所提出的激光扫描电机利用螺旋槽的泵送效应，以降低扫描仪外壳的内压力和降低由旋转多边形反射镜引起的噪声水平。螺旋沟槽气动推力轴承既可以作为粘性真空泵，又可以作为旋转扫描仪转子的支承轴承，可以减小扫描电机的尺寸。本文首先从理论和实验两方面研究了螺旋沟槽气动推力轴承的静、动态特性。将螺旋槽气动推力的泵送特性和承载能力作为静态特性进行了讨论。然后对动刚度和阻尼系数进行了处理。此外，通过与实验结果的比较，验证了理论预测。接下来，我们根据理论预测，使用所提出的轴承设计了一个实际的激光扫描仪电机。对所研制的激光扫描电机进行了多次试验。结果得出如下结论(1)。所提出的螺旋槽气动推力轴承可以同时具有粘性真空泵和支撑轴承的能力(2)。所提出的轴承间隙为2.5 μm的轴承可以在30,000 rpm时将外壳压力降低到0.01 Pa以下(3)。激光扫描测试使用建议的轴承清楚地表明，由于建议的轴承显著降低噪音水平和功率损耗扫描电机的有用性

The objective of this research is to develop a small sized laser scanner motor with a very low noise level. The proposed laser scanner motor uses the pumping effect of spiral grooves in order to reduce the inner pressure of a scanner housing and decrease the noise level caused by a rotating polygon mirror. The size of a scanner motor can be also reduced by using spiral grooved aerodynamic thrust bearings which can act as both a viscous vacuum pump and a supporting bearing for a rotating scanner rotorIn this research, we first investigated the static and dynamic characteristics of a spiral grooved aerodynamic thrust bearing, theoretically and experimentally. We discussed the pumping characteristics and the load capacity of the spiral grooved aerodynamic thrust as static characteristics. Then the dynamic stiffness and damping coefficients were treated. In addition, theoretical predictions were verified by comparing these results with experimental ones. Next, we designed an actual laser scanner motor using the proposed bearings based on the theoretical predictions. Several tests for the manufactured laser scanner motor were carried out. As a results, the following conclusions were obtained(1). The proposed spiral grooved aerodynamic thrust bearing can have the capability of both a viscous vacuum pump and a supporting bearing(2). The proposed bearing with the bearing clearance of 2.5 μmcan reduce the housing pressure to less than 0.01 Pa at 30,000 rpm(3). Leaser scanning test using the proposed bearing clearly shows the usefulness of the proposed bearing due to the remarkable reduction of noise level and power loss of the scanner motor