ISO 8838:2024 すべり軸受 — 水潤滑すべり軸受材料 | ページ 2

Foreword

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This document was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 7, Special types of plain bearings.

Introduction

Water-lubricated bearings are widely used in fields such as submersible pumps, marine stern tubes, hydroelectric generator turbines, water treatment equipment, water valves and rolling equipment for steelmaking.

Water-lubricated plain bearings are used for the following conditions or reasons:

• a) oil or greases cannot be used due to equipment usage conditions;
• b) there is plenty of water available as a lubricant around the equipment;
• c) even if water for lubrication leaks, it does not pollute the environment like oil or grease.

However, when using water as a lubricant, it is necessary to take the following into account:

• water freezes at 0 °C or below and becomes vapor at 100 °C or above, at normal pressure, therefore losing load carrying capacity;
• water has low viscosity in comparison with oil;
• water cannot support a high load because the increase in viscosity that occurs in oil lubrication (elastohydrodynamic lubrication: EHL) when it is under high pressure cannot be expected in water.
• water does not have the ability that oil and grease have to prevent corrosion on shafts and bearings.

While water-lubricated plain bearings have been used in various fields around the world and the water that is used as a lubricant has its own specific features differing from oil, there have been no International Standards that apply to water-lubricated plain bearings thus far.

1 Scope

This document specifies requirements for the selection and use of water-lubricated plain bearing materials used in different equipment and plants under various lubrication conditions, such as

• fluid-film lubrication condition,
• mixed lubrication condition, and
• condition comprising a non-lubrication condition which shifts to a fluid-film lubrication condition.

In addition, this document also specifies requirements for mating (shaft) material, the lubrication method and for items to consider during the design of water-lubricated plain bearing materials.

The water used as a lubricant is pure water, tap water, river water or seawater. This document does not apply to the water solution of chemicals, refrigerants, liquid fuels, etc.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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.

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 1043-1, ISO 4378-1, ISO 4378-2, ISO 4378-3 and ISO 8044 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

Bibliography