Development and evaluation of the magnetic and journal bearing saving electric power using permanent magnet and ER fluid.

轴承是支撑旋转机械的重要机械元件。在保持轴承性能的同时减少摩擦损失是一个不可避免的问题。为此，我们尝试了以ER流体（LC; Liquid Crystal）作为滑动轴承的润滑液，以永磁为磁性轴承元件的节电轴承的开发与评价。本研究的目的是阐明LC轴颈轴承的节能性能，并研究实现永磁轴承的可能性。为了弄清LC轴颈轴承的基本特性，采用在轴颈和轴承之间施加电压的方法对轴承性能进行了测量。结果表明，在摩擦力矩最大减小40%的情况下，可获得相同的承载能力，且轴颈中心轨迹与传统轴承不同。其原理是LC的粘度在最小膜厚区域局部增加。为了抑制摩擦转矩的增加，提高负载能力，提出了采用分布式电极部分施加电压的方法。结果表明：与单电极相比，摩擦力矩更小的情况下，可获得相同的负载能力，且轴颈中心在有限区域内是可控的。从摩擦力矩的测量来看，压力向流动方向增加的上游区域是施加电压的最佳位置，以使摩擦力矩最小。我们只使用永磁体设计磁轴承。我们明确了磁体的排列方式，使其只能用永磁体支撑旋转轴。然而，轴承并没有实现。

Bearing is an important machine element, which supports rotating machinery. It is an inevitable problem to reduce the friction loss, while the performance of the bearing is kept. So we tried development and evaluation of the electric power saving bearings using ER fluid (LC ; Liquid Crystal) as a lubricating fluid of journal bearing, and permanent magnet as elements in magnetic bearing. The objective of this research is to clarify the energy saving performance of LC journal bearing and to examine the possibility of realizing a permanent magnetic bearing.In order to clarify the basic characteristics of LC journal bearing, the measurement of bearing properties by applying voltage between journal and bearing was carried out. We clarified that the same load capacity can be obtained with friction torque reduced maximum of 40%, and that the locus of journal center differs from the conventional bearing. The principle was that the viscosity of LC increased in the minimum film thickness area locally.The method of applying voltage partially using distributed electrodes was proposed for the purpose of increasing load capacity with suppressing the increase of friction torque. The results were that the same load capacity can be obtained with still lower friction torque compared with the case of using single electrode, and that the journal center is controllable in the limited area. From the measurement of friction torque, upstream region of the pressure increasing toward flow direction is the best location for applying voltage to minimize friction torque.We designed the magnetic bearing only using permanent magnet. We clarified the arrangement of the magnet to support the rotating shaft only by permanent magnet. However, the bearing has not come to a realization.