With experience, inspectors can identify the smallest flaw from their sound. Dust, for example, makes an irregular crackling. Ball scratches make a consistent popping and are the most difficult to identify. Inner-race damage is normally a constant high-pitched noise, while a damaged outer race makes an intermittent sound as it rotates.
Bearing defects are further identified by their frequencies. Generally, defects are separated into low, medium, and high wavelengths. Defects are also referenced to the number of irregularities per revolution.
Low-band noise is the effect of long-wavelength irregularities that occur about 1.6 to 10 times per revolution. These are caused by a variety of inconsistencies, such as pockets in the race. Detectable pockets are manufacturing flaws and result when the race is mounted too tightly in multiplejaw chucks.
Medium-hand noise is characterized by irregularities that occur 10 to 60 times per revolution. It is caused by vibration in the grinding operation that produces balls and raceways. High-hand irregularities occur at 60 to 300 times per revolution and indicate closely spaced chatter marks or widely spaced, rough irregularities.
Classifying bearings by their noise characteristics allows users to specify a noise grade in addition to the ABEC standards used by most manufacturers. ABEC defines physical tolerances such as bore, outer diameter, and runout. As the ABEC class number increase (from 3 to 9), tolerances are tightened. ABEC class, however, does not specify other bearing characteristics such as raceway quality, finish, or noise. Hence, a noise classification helps improve on the industry standard.
摘要: 自然界苛刻的工作条件会导致轴承的失效,但是如果遵循一些简单的规则,轴承正常运转的机会是能够被提高的。在轴承的使用过程当中,过分的忽视会导致轴承的过热现象,也可能使轴承不能够再被使用,甚至完全的破坏。但是一个被损坏的轴承,会留下它为什么被损坏的线索。通过一些细致的侦察工作,我们可以采取行动来避免轴承的再次失效。
 论文网关键词: 轴承 失效 寿命 轴承(“Bearing”,日本人称“轴受”)是在机械传动过程中起固定和减小载荷摩擦系数的部件。也可以说,当其它机件在轴上彼此产生相对运动时,用来降低动力传递过程中的摩擦系数和保持轴中心位置固定的机件。轴承是当代机械设备中一种举足轻重的零部件。它的主要功能是支撑机械旋转体,用以降低设备在传动过程中的机械载荷摩擦系数。按运动元件摩擦性质的不同,轴承可分为滚动轴承和滑动轴承两类。  延长轴承寿命英文文献和中文翻译(3):http://www.youerw.com/fanyi/lunwen_34670.html