TOUCHDOWN BEARING

To provide a touchdown bearing capable of preventing a phenomenon that an inner ring abruptly heats up due to contact between the inner ring and a shaft, and thus the temperature difference between the inner ring and an outer ring occurs, thereby causing seizure.SOLUTION: A touchdown bearing that is installed together with a magnetic bearing rotatably supporting a rotational shaft and supports the rotational shaft when the magnetic bearing is out of control, comprises an inner ring with which the rotational shaft slidably contacts in out-of-control, an outer ring arranged against the inner ring, and a plurality of rolling elements incorporated in a rollable manner between the inner and outer rings, where a material of the outer ring has a higher coefficient of linear expansion than that of the inner ring.SELECTED DRAWING: Figure 1 【課題】タッチダウン軸受において、内輪と軸が接触することにより内輪が急激に発熱し、内輪と外輪に温度差が生じ、焼付きが発生することを防ぐ軸受を提供することにある。【解決手段】回転軸を回転自在に支持する磁気軸受と共に設置され、磁気軸受の制御不能時に回転軸を支持するタッチダウン軸受であり、制御不能時に回転軸が摺動接触する内輪と、内輪に対抗して配置された外輪と、内外輪間に転動自在に組み込まれた複数の転動体を備えており、外輪に内輪より線膨張係数の大きい材質を用いることを特徴とする。【選択図】図１