圧電素子の高周波振動を利用したアクティブスクイーズ空気軸受の開発 (第1報)

プロトタイプモデルによる基礎的研究

抄録

Hydrostatic air bearings allow a floating shaft to rotate accurately with compressed air. They are utilized in many fields because of their load carrying capacity, although the shaft does not rotate. However, the installation of additional equipment such as air compressor, regulator and pipelines etc. is required to supply pressured air into the bearing. In this research, piezoelectric actuators oscillate a number of pads surrounding the shaft. In consequence, squeeze air films with load carrying capability are developed. A piezo displacement pattern consists of two functional waveforms. The AC component stimulates the squeeze motion and the other DC component shifts the mean position of oscillating pad. Therefore, application of a controllable piezo-driving pattern allows the shaft to be manipulated. In this paper, the air film characteristics are investigated experimentally for a prototype model with two circular plates of 15mm in radius as oscillating pads. The squeeze air film was able to support the object against the external load of 4.9N with a mean film thickness of 5.5μm. It had the capability to support an external load up to 9.8N with a stiffness of 1.8N/μm. By constructing a simple feedback system, the object was manipulated accurately without contact.