大多数涉及径向轴承的应用都使用一种或多种类型的球或滚子轴承，这些轴承均以称为公差类别的各种精确水平可用。为了统一地对这些公差进行评分，我们将ABEC和RBEC评级量表用作美国行业标准
For ball bearings, these tolerance classes are ABEC 1, ABEC 3, ABEC 5, ABEC 7, and ABEC 9. Similarly, the precision levels for roller bearings (both cylindrical and spherical) are RBEC 1, RBEC 3, RBEC 5, RBEC 7, and RBEC 9. A different rating scale is used for tapered roller bearings.
The ABEC and RBEC classes are identical in values: for both, the higher the class number, the tighter the bearing’s tolerances – thus the better the precision, efficiency, and speed capabilities of the bearing.
ABEC(或RBEC)评级指定公差的年代ize and form for the individual inner and outer rings. Tolerances of size refer to the basic boundary dimensions: the inner diameter of the inner ring, the outer diameter of the outer ring, and the ring widths. Tolerances of form include roundness, taper, runout, and parallelism.
Determining the proper tolerance class for bearings in a particular application is very important. We encourage designers to adhere to the following general guidelines:
Designers should always perform a tolerance stack-up study at both the maximum and minimum material conditions when sizing components, especially when designing miniature ball bearings.
Consider the different precision level options in terms of their direct correlation to bearing performance and lifespan. For example, raceway parallelism can affect bearing torque, so a non-parallel raceway condition will result in torque spikes during rotation. In high-speed applications, excessive bearing runout can result in an imbalance in the rotating mass. Both conditions can lead to unpredictable bearing life and premature failure.
Keep in mind that the higher the precision level, the greater the cost of the bearing.
请记住，具有较高公差类别的轴承旨在用于需要高运行精度，高速旋转和/或低扭矩的精确应用中。常见的例子包括飞机仪器，机床主轴和牙科设备。
On the other hand, bearings with lower tolerance classes are acceptable for use in a wide range of applications, such as automotive, electric motors, and most industrial machinery.
虽然AST轴承工程师乐于指导用户在应用程序的开发过程中选择耐受性课程选择，但在初始设计阶段牢记的最大收获是这样的预防措施：使用比应用程序所要求的较低的公差类别轴承的轴承（通常会导致过早的轴承失败。这导致停机时间增加，维护成本高，收入损失以及在某些极端情况下，人身伤害或生命损失。
It can be tricky to weigh cost against the level of tolerance class required for acceptable performance; however, experts at companies like AST are here to help you solve your questions.
AST轴承
www.astbearings.com
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