ISO 7902-3:2020 PDF

Name: ISO 7902-3:2020 — Hydrodynamic plain journal bearings under steady-state conditions — Circular cylindrical bearings — Part 3: Permissible operational parameters
SKU: ISO 7902-3:2020
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Hydrodynamic plain journal bearings under steady-state conditions — Circular cylindrical bearings — Part 3: Permissible operational parameters

Название (английский):

ISO 7902-3:2020

Hydrodynamic plain journal bearings under steady-state conditions — Circular cylindrical bearings — Part 3: Permissible operational parameters

Статус документа:: Отменён
Формат:: Электронный (PDF)
Количество страниц:: 9
Дата публикации:: 9 июня 2020 г.
Издание:: ISO IS 7902 edition 2 version 1
ICS:: 21.100.10

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Описание (английский):

This document specifies empirical permissible values for hlim, Tlim and . The empirical values stated can be modified for certain applications, for example if information supplied by the manufacturer is to be taken into account. The descriptions of the symbols and calculation examples are given in ISO 7902-1.

Abstract

Похожие стандарты

Стандарты, упомянутые в описании

Overview

ISO 7902-3:2020 - "Hydrodynamic plain journal bearings under steady-state conditions - Circular cylindrical bearings - Part 3: Permissible operational parameters" specifies empirical limits and assessment methods for the operational parameters that ensure reliable tribological performance of circular cylindrical (plain journal) bearings. The standard defines how to evaluate minimum lubrication film thickness, effective waviness, maximum permissible specific bearing load and bearing temperature, and gives guidance on bearing clearance. It complements the calculation procedure in ISO 7902-1 and is intended to prevent wear, mechanical damage and thermal degradation.

Key topics and requirements

Minimum permissible lubricant film thickness (h_lim):

Formula-based determination that accounts for surface roughness (Rz), misalignment and deflection.
Empirical tables provide practical h_lim values (typical range ~3 µm to ~18 µm depending on shaft diameter and peripheral speed).
Notes on running-in, filtration and material selection to reduce wear risk.

Effective waviness (h_wav,eff) and limits:

Methods (figures and coefficients E, G) to evaluate waviness influence for the most unfavorable shaft position.
Procedure to determine maximum permissible effective waviness and absolute waviness.

Maximum permissible specific bearing load (p_lim):

Empirical load limits by bearing material group (examples: Pb/Sn and Cu-based alloys; values typically of order MPa; see Table 3 for material-specific guidance).
Guidance on starting loads and when hydrostatic assist may be required.

Thermal limits (T_lim):

Maximum permissible bearing temperatures depend on bearing material and lubricant; tables give empirical values for different lubrication regimes and oil flow ratios.
Emphasis on viscosity loss, lubricant ageing (>80 °C) and reduced load capacity at elevated temperatures.

Bearing clearance (ψ):

Provides an empirical sizing approach and a preferred series of mean relative clearances (0.56‰ to 3.15‰) to balance temperature and hydrodynamic performance.

Practical assessment aids: Figures, worked examples and empirical tables to apply limits in design and verification.

Applications

Design and specification of hydrodynamic plain journal bearings for engines, gearboxes, turbines, pumps and rotating machinery.

Bearing selection, tolerance/clearance definition and lubrication system design.

Condition assessment, maintenance planning and failure prevention (wear, seizure, thermal degradation).

Use in calculations and simulations that follow ISO 7902-1 for steady-state bearing performance.

Related standards

ISO 7902-1 (Calculation procedure for circular cylindrical plain journal bearings) - normative reference.

Material and bearing-specification standards referenced in the document (e.g., ISO 4381, ISO 4382 series).

Keywords: ISO 7902-3:2020, hydrodynamic plain journal bearings, circular cylindrical bearings, permissible operational parameters, lubrication film thickness, waviness, bearing load, bearing temperature, bearing clearance, bearing design, tribology.

ISO 7902-3:2020 PDF

Abstract

Похожие стандарты

Overview

Key topics and requirements

Applications

Who uses this standard

Related standards

Технические детали

SIST ISO 7902-1:2021

Hydrodynamic plain journal bearings under steady-state conditions - Circular cylindrical bearings - Part 1: C…

SIST ISO 4381:2015

Plain bearings - Tin casting alloys for multilayer plain bearings

BS ISO 4382-2:2021

Plain bearings. Copper alloys. Wrought copper alloys for solid plain bearings.