The vibration value of the bearing is an important parameter indicating the normal operation of the bearing. Today, let's talk about the testing methods for bearing vibration. 

1. Testing method for speed-type bearing vibration measuring instrument 

Install the tested bearing onto the mandrel so that its inner end face is tightly against the shoulder of the shaft. For cylindrical roller bearings, the end faces of the inner and outer rings should be kept in the same plane. 

Deep groove ball bearings should be tested on both the front and rear sides. For angular contact and tapered roller bearings, the tests should be conducted according to the direction in which they bear the axial load. For NJ type cylindrical roller bearings, the inner ring flange end face should be installed against the shaft shoulder for testing. For NF type cylindrical roller bearings, the outer ring flange surface should face outward. For N type and NU type cylindrical roller bearings, the reference surface should be installed towards the inner shaft shoulder. During the testing process, it is necessary to ensure that the rings do not undergo axial displacement. 

Apply the specified axial or radial load to the outer ring of the bearing, and take the measurement point at the halfway point of the outer ring width. After starting the main shaft, when the indicating instrument is stable, read the vibration values of the three frequency bands respectively. The measurement time for the vibration velocity signal of each measurement point should be no less than 0.5 seconds. 

2. Testing methods for acceleration-type bearing vibration measuring instruments 

Under the specified test conditions, allow the bearing to operate for a period of time to achieve a stable vibration state of the bearing. At each measurement position, read the bearing vibration value under such conditions. 

During single-sided measurement, the average value of the three measured values of the tested bearing is taken as the vibration acceleration level of this set of bearings. During double-sided measurement, the larger value of the average of the single-sided three-point measurements of the tested bearing is taken as the vibration acceleration level of this set of bearings. The maximum value of the vibration acceleration peak at each measurement point of this set of bearings is taken as the vibration acceleration peak of this set of bearings. The maximum value of the peak factor at each measurement point of this bearing is taken as the acceleration peak factor of this bearing.