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4. NAWGL

DIN Standards Committee Rolling Bearings and Plain Bearings

Overview

The document (ISO 15242-2) has been prepared by Technical Committee ISO/TC 4 "Rolling bearings", the secretariat of which is held by SIS (Sweden). The German body responsible for this standard series is Working Committee NA 118-01-04 AA "Toleranzen, Prüf- und Messverfahren" ("Tolerances, measuring and gauging principles and methods") of the Standards Committee Rolling Bearings and Plain Bearings (NAWGL) at DIN. 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°, under established test conditions. It covers radial ball bearings with cylindrical bore and outside surface, except bearings with filling slots and three- and four-point-contact ball bearings. Vibration of rotating rolling bearings is a complex physical phenomenon dependent on the conditions of operation. Measuring the vibration output of an individual bearing under a certain set of conditions does not necessarily characterize the vibration output under a different set of conditions or when the bearing becomes part of a larger assembly. Assessment of the audible sound generated by the mechanical system incorporating the bearing is complicated further by the influence of the interface conditions, the location and orientation of the sensing device, and the acoustical environment in which the system operates. Assessment of airborne noise that, which for the purpose of this document, can be defined as any disagreeable and undesired sound, is further complicated by the subjective nature of the terms "disagreeable" and "undesired". Structure-borne vibration can be considered the driving mechanism that ultimately results in the generation of airborne noise. Only selected methods for the measurement of the structure-borne vibration of rotating rolling bearings are addressed in the current edition of ISO 15242. Vibration of rotating rolling bearings can be assessed by any of a number of means using various types of transducers and test conditions. No simple set of values characterizing vibration of a bearing is adequate for the evaluation of the vibratory performance in all possible applications. Ultimately, a knowledge of the type of bearing, its application and the purpose of the vibration testing (for example as a manufacturing process diagnostic or an assessment of product quality) is required to select the most suitable method for testing. The field of application for standards on bearing vibration is, therefore, not universal. However, certain methods have established a wide enough level of application to be considered as standard methods for the purposes of this part of ISO 15242. This part of ISO 15242 serves to define the detailed method for assessing vibration of radial ball bearings with cylindrical bore and outside surface on a test rig.

Document: references other documents

Responsible national committee

NA 118-01-04 AA - Measuring and gauging principles and methods