ABMA 15242-4:2012 pdf download

ABMA 15242-4:2012 pdf download.Rolling bearings — Measuring methods for vibration
1 Scope
This part of ISO 1 5242 specifies vibration measuring methods for single-row and double-row radial cylindrical roller bearings, under established test conditions. It covers single-row and double-row radial cylindrical roller bearings with cylindrical bore and outside surface.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 286-2, ISO system of limits and fits — Part 2: Tables of standard tolerance grades and limit deviations for holes and shafts ISO 554, Standard atmospheres for conditioning and/or testing — Specifications ISO 558, Conditioning and testing — Standard atmospheres — Definitions ISO 1 1 32-1 , Rolling bearings — Tolerances — Part 1: Terms and definitions ISO 2041 , Vibration and shock — Vocabulary ISO 3205, Preferred test temperatures ISO 3448, Industrial liquid lubricants — ISO viscosity classification ISO 5593, Rolling bearings — Vocabulary ISO 1 5242-1 :2004, Rolling bearings — Measuring methods for vibration — Part 1: Fundamentals
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1 1 32-1 , ISO 2041 , ISO 5593 and ISO 1 5242-1 apply.
4 Measurement process
4.1 Speed of rotation The default speed of rotation shall be 30 s -1 (1 800 r/min) for bearings with outside diameter up to 1 00 mm and 1 5 s -1 (900 r/min) for outside diameters larger than 1 00 up to 200 mm. Tolerance of the speed of rotation shall be – +1 2 % of the specified nominal value. Other speeds and tolerances may be used by agreement between the manufacturer and the customer; e.g. it may be necessary to use a higher speed for bearings in the smaller size range [40 s -1 to 60 s -1 (2 400 r/min to 3 600 r/min)] in order to obtain an adequate vibration signal. Conversely, it may be necessary to use a lower speed for bearings in the larger size range [7,5 s -1 to 1 0 s -1 (450 r/min to 600 r/min)] to avoid possible roller and raceway damage. 4.2 Bearing radial and axial loads The bearing load shall be in the radial direction with default values as specified in Table 1 .Other radial loads and tolerances may be used by agreement between the manufacturer and the customer; e.g. depending on bearing design and lubricant used, it may be necessary to use a higher load to prevent roller/raceway slip, or a lower load to avoid possible roller, rib and raceway damage. For bearings capable of taking axial load, an axial load of up to 30 N shall be applied on the outer ring to ensure stable operation. The method of applying the radial and axial loads is described in 6.3.3. NOTE Default values for radial loads are resultant values. Actual values depend on load angle used (see Figure 3)
5 Measurement and evaluation methods
5.1 Physical quantity measured The default physical quantity to be measured is vibration velocity, n r.m.s. (µm/s), in the radial direction. 5.2 Frequency range The velocity signal shall be measured in one or more bands with default frequency ranges as specified in Table 2.NOTE Other frequency ranges may be considered by agreement between the manufacturer and the customer in those instances where specific ranges have greater importance to successful operation of the bearing. The use of spectral analysis of the vibration signal is an alternative. 5.3 Peak measurement Detection of peaks or spikes in the time domain velocity signal, usually due to surface defects and/or contamination in the test bearing, may be considered as a supplementary option by agreement between the manufacturer and the customer. Various evaluation methods exist depending on the bearing type and the application. 5.4 Testing sequence Single-row and double-row radial cylindrical roller bearings shall be tested with the radial load applied in a radial direction on the outer ring and perpendicular to the inner ring axis. An axial load may be necessary to ensure stable operation. If the axial load is used, it is applied from one side of the outer ring. For double-row radial cylindrical roller bearings the test should be repeated, if the design allows, with the axial load on the other side of the outer ring. For diagnostic purposes, performing multiple measurements with the outer ring in different angular positions relative to the pick-up is appropriate. For acceptance of the bearing, the highest vibration reading for the appropriate frequency band shall be within the limits mutually agreed between the manufacturer and the customer. For test duration, see ISO 1 5242-1 :2004, 6.5.