高DN值滚子轴承保持架断裂分析

Analysis of roller bearing cage broken under high DN value

对高DN值(轴承内径与转速的乘积)滚子轴承保持架断裂的故障机理进行仿真,采用超高周疲劳理论对仿真结果进行分析,结果表明:以往基于高周疲劳概念的保持架设计方法不适用于高DN值轴承保持架,超长寿命期内造成断裂所需的应力远低于材料的疲劳极限。造成高DN值滚子轴承保持架断裂的主要应力来自高转速带来的离心应力,而兜孔圆角过小导致应力集中过大是造成轴承保持架断裂主要原因,因此增大保持架兜孔圆角或清根能够降低局部应力集中,有利于防止保持架的断裂,提高轴承的可靠性。

The failure mechanism of high DN value(bearing inner diameter multiply speed) bearing cage was analyzed. The results of roller bearing cage broken under the theory of ultra-high cycle fatigue showed that the method of designing of cage based on high cycle fatigue didn’t apply to high DN value cage. The stress causing fracture within over-long design life was far below fatigue limit of the material. The centrifugal stress caused by high speed contributed a lot to high DN value bearing cage fracture, and the main reason causing cage fracture was attributable to stress concentration because of the small pocket fillet. Therefore increasing pocket fillet and clean-up machining would help avoid cage fracture, and increase reliability of bearings.