ABMA 15242-2:2016 pdf download

ABMA 15242-2:2016 pdf download.Rolling bearings — Measuring methods for vibration
1 Scope
This part of ISO 15242 specifies vibration measuring methods for single-row and double-row radial ball bearings, with a contact angle up to and including 45°. It covers radial ball bearings with cylindrical bore and outside surface, except bearings with filling slots and three- and four-point-contact ball bearings.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. 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, Geometrical product specifications (GPS) — ISO code system for tolerances on linear sizes — Part 2: Tables of standard tolerance classes and limit deviations for holes and shafts ISO 2041:2009, Mechanical vibration, shock and condition monitoring — Vocabulary ISO 5593, Rolling bearings — Vocabulary ISO 15242-1:2015, 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 2041, ISO 5593 and ISO 15242-1 apply.
4 Measurement process
4.1 Rotational frequency The default rotational frequency shall be 1 800 min −1 (30 s −1 ). The tolerance shall be − + 2 1 % of the nominal rotational frequency. Other rotational frequencies and tolerances may be used by agreement between the manufacturer and the customer, for example, it may be necessary to use a higher rotational frequency for bearings in the smaller size range (e.g. 3 600 min −1 ) in order to obtain an adequate vibration signal. Conversely, it may be necessary to use a lower rotational frequency for bearings in the larger size range (e.g. 700 min −1 ) to avoid possible ball and raceway damage.Other axial loads and tolerances may be used by agreement between the manufacturer and the customer, for example, depending on bearing design, rotational frequency and lubricant used, it may be necessary to use a higher load to prevent ball/raceway slip or a lower load to avoid possible ball and raceway damage.
5 Measurement and evaluation methods
5.1 Physical quantity measured The default physical quantity to be measured is root mean square vibration velocity, ν rms (µm/s), in the radial direction. 5.2 Frequency domain The vibration velocity shall be analysed in one or more bands with default frequency ranges as specified in Table 2.Narrow band spectral analysis of the vibration signal may be considered as a supplementary option. 5.3 Measurement of pulses and spikes Detection of pulses or spikes in the time domain velocity signal, usually due to surface defects and/or contamination in the measured bearing, may be considered as a supplementary option. Various evaluation methods exist. 5.4 Measurement All bearings, except for single-row angular contact ball bearings, shall be measured with the axial load applied from one side of the stationary ring and the measurement repeated with the axial load on the other side of the stationary ring. Single-row angular contact ball bearings shall be measured in their foreseen axial load carrying direction only. The greatest vibration reading for each frequency band shall be within the limits. For diagnostic purposes, performing multiple measurements with the stationary ring in different angular positions relative to the transducer is appropriate. For measurement duration, see ISO 15242-1:2015, 6.5.
6 Conditions for measurement
6.1 Bearing conditions for measurement 6.1.1 Prelubricated bearings Prelubricated (greased, oiled or solid lubricated) bearings, including sealed and shielded types, shall be measured in the as-delivered condition. 6.1.2 Non-prelubricated bearings Since contamination affects vibration, the bearings shall be effectively cleaned, taking care not to introduce contamination or other sources of vibration. NOTE Some preservatives meet the lubrication requirements for vibration measuring. In this case, it is not necessary to remove the preservative. Non-prelubricated bearings shall be adequately lubricated with fine filtered oil, typically having a viscosity in the range of 10 mm 2 /s to 100 mm 2 /s, appropriate to bearing type and size. The lubrication procedure shall include some running-in to achieve homogeneous distribution of the lubricant within the bearing.