ISO/TC 123 - Plain bearings

This document specifies a method of improving test result comparability by evaluating the stresses in the bearing layers leading to fatigue (see Annex A). A similar evaluation is required in practical applications. Because the stresses are the result of pressure build-up in the hydrodynamic film, it is essential to fully state the conditions of operation and lubrication. In addition to dynamic loading, dimensional and running characteristics, the inclusion of the following adequately defines the fatigue system: a)  under conditions of dynamic loading the minimum bearing oil film thickness as a function of time and location to ensure no excessive local overheating or shearing as a result of mixed lubrication when running in; b)  the distribution of pressure circumferentially and axially with time under dynamic loading; c)  from this the resulting stresses in the bearing layers as a function of time and location, especially the maximum alternating stress. Furthermore, bearing fatigue can be affected by mixed lubrication, wear, dirt, tribochemical reactions and other effects encountered in use thus complicating the fatigue problem. This document is therefore restricted to fatigue under full hydrodynamic separation of the bearing surfaces by a lubricant film. This document applies to oil-lubricated plain cylindrical bearings, in test rigs and application running in conditions of full hydrodynamic lubrication. It comprises dynamic loading in bi-metal and multilayer bearings. NOTE     The number of practical applications with different requirements has led to the development of many bearing test rigs. If the conditions of lubrication employed on these test rigs are not defined in detail, test results from different rigs are generally neither comparable nor applicable in practice. Different test rigs can yield inconsistent ranking among equal materials.

This document specifies a calculation method for oil-lubricated hydrodynamic plain bearings with complete separation of the thrust collar and tilting pad thrust bearing surfaces by a film of lubricant. This document applies to plain thrust bearings with tilting-type sliding blocks (tilting pads), where a wedge-shaped lubrication clearance gap is automatically formed during operation. The ratio of width to length of one pad can be varied in the range B/LÂ =Â 0,5 to 2. This document is not applicable to heavily loaded tilting pad thrust bearings. NOTEÂ Â Â Â Â Â Equivalent calculation procedures exist that enable operating conditions to be estimated and checked against acceptable conditions. The use of them is equally admissible.

This document specifies the dimensions and tolerances for inserted thermoplastic bushes used as plain bearings with or without lubrication grooves in accordance with ISO 12128. These thermoplastic bushes are dimensionally exchangeable to wrapped bushes according to ISO 3547-1. This document is not applicable to reinforced plastics.

This document specifies, in graphic form, characteristic values used in the calculation of oil-lubricated plain journal bearings with drainage grooves.

This document specifies the requirements for an engine bearing test rig that uses an actual connecting rod to determine plain bearing performance in automotive engines, evaluating fundamental bearing properties such as seizure resistance, wear resistance, fatigue resistance and resistance to the impact of foreign material.

This document specifies in accordance with ISO 12301 the checking of the wall-thickness of thin-walled half bearings with or without flange and describes the necessary checking methods and measuring equipment. It applies to a maximum bearing diameter of 150 mm. It can be applied to a bigger diameter, provided that there is an agreement between the supplier and the user.

The aim of this document is to achieve designs of plain bearings that are reliable in operation, by the application of a calculation method for oil-lubricated hydrodynamic plain bearings with complete separation of the thrust collar and plain bearing surfaces by a film of lubricant[1]. This document applies to plain thrust bearings with incorporated wedge and supporting surfaces having any ratio of wedge surface length lwed to length of one pad L. It deals with the value lwed/L = 0,75 as this value represents the optimum ratio[2]. The ratio of width to length of one pad can be varied in the range B/L = 0,5 to 2. The calculation method described in this document can be used for other incorporated gap shapes, e.g. plain thrust bearings with integrated baffle, when for these types the numerical solutions of Reynolds equation are known. The calculation method serves for designing and optimizing plain thrust bearings e.g. for fans, gear units, pumps, turbines, electrical machines, compressors and machine tools. It is limited to steady-state conditions, i.e. load and angular speed of all rotating parts are constant under continuous operating conditions. Dynamic operating conditions are not included.

This document specifies guide values for avoiding damage to thrust-pad bearings in service. The explanation of the symbols as well as examples for calculation are given in ISO 12131-1.

This document specifies the general principles, assumptions and preconditions for the calculation of multi-lobed and tilting-pad journal bearings by means of an easy-to-use calculation procedure based on numerous simplifying assumptions. For a reliable evaluation of the results of this calculation method, it is indispensable to consider the physical implications of these assumptions as well as practical experiences for instance from temperature measurements carried out on real machinery under typical operating conditions. Applied in this sense, this document presents a simple way to predict the approximate performance of plain journal bearings for those unable to access more complex and accurate calculation techniques. The calculation method serves for the design and optimisation of plain bearings, for example in turbines, compressors, generators, electric motors, gears and pumps. It is restricted to steady-state operation, i.e. in continuous operating states the load according to size and direction and the angular velocity of the rotor are constant. Unsteady operating states are not recorded. The stiffness and damping coefficients of the plain journal bearings required for the linear vibration and stability investigations are indicated in ISO/TS 31657-2 and ISO/TS 31657-3.

This document specifies the characteristic values for selected tilting-pad journal bearings with four or five centrally or eccentrically supported tilting pads and with angular spans of pad sliding surfaces of Ω = 80°, 60° and 45°. The functions plotted and listed in table form below are required for the operationally safe design of hydrodynamic tilting-pad journal bearings according to ISO/TS 31657-1. They are based on the presumptions and boundary conditions indicated there and only apply to stationary operating states. The symbols used are explained in ISO/TS 31657-1; calculation examples are also included there. The calculation method described in ISO/TS 31657-1 can also be used for other tilting-pad journal bearing designs, if the numerical solutions of the basic equations are available in the same manner for these designs.

This document specifies a calculation procedure for oil-lubricated hydrodynamic plain bearings, with complete separation of the shaft and bearing sliding surfaces by a film of lubricant, used for designing plain bearings that are reliable in operation. It deals with circular cylindrical bearings having angular spans, Ω, of 360°, 180°, 150°, 120°, and 90°, the arc segment being loaded centrally. Their clearance geometry is constant except for negligible deformations resulting from lubricant film pressure and temperature. The calculation procedure serves to provide dimensions and optimize plain bearings in turbines, generators, electric motors, gear units, rolling mills, pumps, and other machines. It is limited to steady-state operation, i.e. under continuously driven operating conditions, with the magnitude and direction of loading as well as the angular speeds of all rotating parts constant. It can also be applied if a full plain bearing is subjected to a constant force rotating at any speed. Dynamic loadings (i.e. those whose magnitude and direction vary with time), such as those that can result from vibration effects and instabilities of rapid-running rotors, are not taken into account. NOTE Equivalent calculation procedures exist that enable operating conditions to be estimated and checked against acceptable conditions. The use of them is equally admissible.

This document specifies design characteristics for side flange bearings for the size range 9 to 28, as well as design characteristics for shafts. It is applicable to side flange bearings used mainly in electrical and turbo engineering industries.

This document establishes the permissible operational parameters in terms of guide values for the calculation of selected multi-lobed and tilting-pad journal bearings. In order to attain a sufficient operational safety of multi-lobed and tilting-pad journal bearings by the calculation according to ISO/TS 31657-1, it is necessary for the operational characteristic value hmin to be significantly above the permissible operating parameter hlim,tr and for the permissible operating parameters Tlim and plim not to be exceeded by the calculated operational characteristic values Tmax and pmax. The guide values represent geometrically and technologically founded operational limiting values in the tribological system of plain bearings. They are empirical values that enable sufficient operational safety even in the event of smaller disturbing influences (see ISO/TS 31657-1). The empirical values indicated can be modified for special application areas. NOTE The explanations for the symbols and calculation examples are contained in ISO/TS 31657-1.

This document specifies the characteristic values for selected two-, three- and four-lobe bearings. The functions plotted and listed in table form below are required for the operationally safe design of hydrodynamic multi-lobed journal bearings according to ISO/TS 31657-1. They are based on the presumptions and boundary conditions indicated there and only apply to stationary operating states. The symbols used are explained in ISO/TS 31657-1; calculation examples are also included there.

This document specifies design characteristics for pillow blocks for size ranges 9 to 28 and 35 to 71, as well as design characteristics for shafts. It is applicable to pillow blocks used mainly in electrical and turbo engineering industries.

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.

This document specifies the values of the basic functions used in the calculation procedure for oil-lubricated circular cylindrical hydrodynamic bearings under conditions of full lubrication. The values are given for the assumptions and boundary conditions given in ISO 7902-1. The values necessary for the calculation can be determined from the tables of bearing characteristics, the graphs and from the formulae. The descriptions of the symbols used and calculation examples are given in ISO 7902-1.

This document specifies the dimensions and tolerances applicable to sintered bearings for the following ranges of inside diameters: — cylindrical bearings: 1 mm to 60 mm; — flanged bearings: 1 mm to 60 mm; — spherical bearings: 1 mm to 20 mm.

This document specifies, following ISO 12301, the checking of the outside diameter of wrapped bushes (ISO 3547‑2:2017, methods A, B and D) and describes the necessary checking methods and measuring equipment. NOTE The dimensions and tolerances of wrapped bushes are given in ISO 3547‑1. Checking the wall thickness is the subject of ISO 3547‑7.

The document specifies, following ISO 12301, the checking of the inside diameter of wrapped bushes (see ISO 3547‑2:2017, method C) and describes the necessary checking methods and measuring equipment. NOTE 1 All dimensions in this document are given in millimetres except where otherwise noted/designated. NOTE 2 The dimensions and tolerances of wrapped bushes are given in ISO 3547‑1. NOTE 3 Checking of the wall thickness is the subject of ISO 3547‑7. NOTE 4 Checking of the outside diameter of wrapped bushes is the subject of ISO 3547‑5.

This document describes, following ISO 12301, the checking methods and measuring equipment used for measuring the total wall thickness of thin-walled bushes in the finished state. NOTE All dimensions in this document are given in millimetres.

This document specifies dimensions for lubrication holes, grooves and pockets for bearing bushes. These dimensions can be entered, for example on drawings, using the designation examples. Their use depends in particular on the specific operating conditions. In addition, it enables the user to assign the different types of lubricant feed and distribution to solid and steel-backed plain bearing bushes made of copper alloys, aluminium alloys, thermosetting plastics, thermoplastics or artificial carbon. NOTE Different types of lubricant feed and distribution for plain bearing bushes made of sintered metals have not been specified due to the fact that these bushes are soaked with lubricant. Plain bearing bushes made of artificial carbon are not lubricated with oil or grease.

This document specifies design characteristics for centre flange bearings for the size range 9 to 28, as well as design characteristics for shafts. It is applicable to centre flange bearings used mainly in electrical and turbo engineering industries.

This document specifies the derivation of mathematical functions to be applied when calculating tilting pad thrust bearings. This document is not applicable to heavily loaded tilting pad thrust bearings.

This document specifies guide values for the calculation of tilting pad thrust bearings as described in ISO 12130-1. The empirical values given can be modified for specific fields of application. This document is not applicable to heavily loaded tilting pad thrust bearings.

This document defines requirements for the testing of lubricated plain journal bearings in test rigs, running under conditions of hydrodynamic or mixed lubrication, during bearing and/or material development. It deals with both static and dynamic loading in solid and multi-layer journal bearings. It is not applicable to the testing of dynamic characteristics of lubricant film in journal bearings applied in calculation of vibration and stability of turbo-rotors. NOTE It is intended that further details of test procedures be established when carrying out testing based on this document.

This document specifies a calculation method of oil-lubricated plain journal bearings without drainage grooves under steady-state conditions. It applies to hydrostatic plain journal bearings under steady-state conditions. In this document, only bearings without oil drainage grooves between the recesses are taken into account.

This document lists, in graphic form, characteristic values used in the calculation of oil-lubricated plain bearings without drainage grooves.

This document describes a method for comparing the performance test results of foil journal bearings, which are lubricated by air (gas) and supported by the gas-dynamic force generated via the rotations of the rotating shaft. The test procedure proposed in this document aims to predict and evaluate the static load capacity, friction coefficient and lifetime of foil journal bearings and compare the results of these parameters under different test conditions, i.e. at varying dimensions of foil bearing, rotational speed of a shaft, pressure and humidity of the surroundings. The magnitude of the static load capacity can change according to the test setting, as the test conditions can be changed. The test method described in this document has the following application coverage. a) The criterion for evaluating the static load capacity is the steady-state condition; i.e. the method is applicable under limited operating conditions with uniform magnitude, load direction and rotational speed. b) The evaluation procedure can be applied only if the foil journal bearing is under a uniform rotating inertia at an arbitrary rotational speed. c) The dynamic load with time-variant magnitude and direction is not considered.

This document defines, describes and classifies the characteristics of damage occurring in service to hydrodynamically lubricated metallic plain bearings and journals. It assists in the understanding of the various characteristic forms of damage which can occur. Consideration is restricted to damage characteristics which have a well-defined appearance and which can be attributed to particular damage causes with a high degree of certainty. Various appearances are illustrated with photographs and diagrams.

This document defines, describes and classifies the characteristics of damage occurring in service in hydrodynamically lubricated metallic plain bearings due to cavitation erosion, together with possible countermeasures. It assists in understanding the various characteristic forms of damage which can occur. Consideration is restricted to damage which has a well-defined appearance and which can be attributed to particular causes with a high degree of certainty. Various appearances are illustrated with photographs and diagrams.

This document specifies tolerances on form and position as well as the surface roughness of shafts, flanges and thrust collars as used in plain bearing units. It is applicable to journal or thrust plain bearing units or to a combination of both, installed either horizontally or vertically. This document is not applicable to crankshaft bearing units in combustion engines.

This document specifies an ultrasonic testing method for determining bond defects between the bearing metal and the backing. The test can be performed on metallic multilayer plain bearings consisting of steel- or copper-based material backings lined with bearing metal based on lead and tin, with layer thicknesses greater than or equal to 0,5 mm. For cast iron backings, this document is applicable with restrictions. The ultrasonic signal reflected by the bond interface between the bearing metal and the backing is used to determine bonding defects. Ultrasonic testing is not possible on edge zones of sliding surface, flange sides, joint areas, oil holes, grooves, etc. in a range of less than half the diameter of the ultrasonic probe because of undefined reflections. The same applies to bearings with dovetail keying grooves at the bond. Ultrasonic testing of bond does not apply along the edges of the dovetails. Evaluation of the bond on the visible transition from the backing to the bearing metal (on end faces or joint faces) is only practicable by the penetrant testing method specified in ISO 4386-3. This document only describes in detail the pulse-echo method. Within the meaning of this document, the ultrasonic method only permits a qualitative evaluation of the bonding and not a quantitative determination of the bond strength. The ultrasonic bond test differs only between bond and bond defect.

This document specifies a tensile test method for determination of the bond strength between the bearing metal and the backing. The test can be applied to multilayer plain bearings with bearing metals based on lead, tin, copper or aluminium. For tested layer thicknesses ≥ 2 mm, a raw lining thickness of a minimum additional 1 mm is necessary. The backings are from steel, cast steel or copper alloys. The bond strength test does not apply to bearings with cast iron backing. The test applies to all thrust bearings and to journal bearings with an inner diameter of backing ≥ 90 mm. The test can be used for comparative investigations into the influence on the bond strength of various processes and types of material. In addition, the test is suitable for production control and for process qualification of bearing production. For non-destructive ultrasonic testing of the bond between bearing metal and backing for bearing metal layer thicknesses ≥ 2 mm, see ISO 4386-1.

This document specifies a method for the determination of the endurance limit in fatigue of plain strips of multilayer bearing materials. Additionally, it provides the opportunity of studying the influence on the strips of hydraulic pressure and variable temperature.

This document provides requirements and guidance on lubricant supply arrangements and monitoring for liquid-lubricated bearings (plain bearing assemblies) such as those specified in ISO 11687 (all parts). This document is intended to assist the design of oil-based lubrication systems for hydrodynamic plain bearings mainly to be used in large-scale rotating machinery for power generation, industry and transportation. This document focuses on the most important requirements and characteristics of lubricant supply arrangements and monitoring for plain bearings. Additional standards such as ISO 10438‑1, ISO 10438‑2 and ISO 10438‑3 would be needed to design complete low-pressure or high-pressure lubrication systems, along with their corresponding components. Wherever this document specifies a particular form of solution, whether design or operation, different solutions can be selected provided they are justified by engineering assessment or reference to similar systems already in operation.

This document specifies a system of fits applicable to metallic plain bearings used in general engineering for mean relative bearing clearances, ψm, of 0,56 ? up to 3,15 ?. Other clearance ranges can be used depending upon the requirements in specific applications. This system of fits is not applicable to half‑bearings and bushes which, due to their special characteristics, are not measured by diameter but by wall thickness, and which are dimensionally changed on assembly. It is not applicable to profile bore or tilting pad bearings, or to cases where specific tolerances have been established by consideration of the bearing performance at both extremes of clearance. This document is applicable preferably to rotating machine parts and shafting, but it can be used similarly in other ranges of application.

This document specifies parameters for the hardness testing of compound materials for plain bearings made from steel and bearing metal with bearing metals based on copper and aluminium, manufactured by casting, sintering or bonding. It represents a supplement to the existing ISO publications on hardness testing and, therefore, includes only the extensions and restrictions to be observed compared to those publications. The measuring method applied depends on the bearing metal layer thickness, its hardness and its structure.

This document specifies the method for comparing performance evaluation results for a foil thrust bearing that supports load with aerodynamic force generated by the rotation of a driving shaft and lubricates using air, not lubricating oil. The test procedure explained in this document measures and evaluates the static load capacity, bearing torque, friction coefficient and lifetime of the foil thrust bearing and compares the test results to those for different test conditions. The measured static load capacity can be varied depending on the capabilities of the test device used.

This document specifies requirements for tilting pad bearing lining materials (metals and polymers), backing metals and pivots.

This document specifies requirements and guidance on the storage, transportation, handling, installation, operation and replacement of plain bearings and related parts.

This document specifies dimensions and tolerances for cylindrical and flanged bushes with internal diameter, d1, in the range 6 mm to 200 mm. It applies to solid mono‑metal copper alloy bushes to be used as plain bearings with and without oil holes and oil grooves.

Directed lubrication is an advanced technology that is capable of reducing the power loss and improving the performance of tilting pad type bearings. Unlike flooded lubrication, where the bearing components remain permanently submerged in an oil filled housing, with directed lubrication the components are not submerged and the oil is delivered from an external source directly to the working surfaces of the tilting pads after which it falls freely away to be drained from the bottom of the housing. There are several alternative methods of realising the benefits of directed lubrication in tilting pad bearing designs. As an example, this document specifies a spray nozzle type directed lubrication system where lubricant is supplied to each pad through nozzles mounted between the pads in tilting pad thrust and journal bearings. The design concept of this type of lubrication is described.

This document specifies the material compositions and required properties of fluid film bearings used for vehicular turbochargers.

This document specifies a range of ring type thrust washers for general purpose use with wrapped bushes as specified in ISO 3547 (all parts). It applies to thrust washers having inside diameters from 6 to 80 mm. NOTE It is not expected that all the sizes listed will be available from stock but the standardization of sizes is aimed at making economies in tooling costs.

This document specifies a non‑destructive penetrant testing for determining bond defects and discontinuities in the sliding surface of the bearing. The penetration method is used to detect a) bond defects in the transitional area between the bearing backing/bearing material on the end faces and joint faces of multilayer plain bearings which cannot be detected by the ultrasonic testing method specified in ISO 4386‑1, and b) discontinuities in the sliding surface of the bearing. The penetration method is applicable, in principle, to finished multilayer plain bearings. The bond test is usually carried out on cast multilayer plain bearings, with a backing consisting of steel, cast steel or cast bronze. It can also be used as a non-production method to aid detection of manufacturing process defects with other bearing material types. Bearing backings which cannot be tin-plated, or only with difficulty, such as perlitic cast iron, rust-resistant steel and cast aluminium, cannot be tested since no bond is possible between the bearing material and bearing backing.

This document specifies the dimensions and designations of cylindrical and flanged wrapped bushes made of mono and multi-layer bearing material for plain bearing applications.

This document specifies a method of determining the σ0,01*‑limit for the steel backing of thin‑walled multilayer half bearings for bearing diameters up to 80 mm. It can also be used for bearing diameters up to 160 mm.

This document gives requirements and guidance to obtain the optimum bond between backing and bearing metal for thick-walled multilayer plain bearings. This optimum bond depends on the chemical composition, the state of stress, the structural arrangement and the machining of the bond surface of the backings. NOTE Control of the manufacturing process is an important requirement to achieve an optimum bond between backing material and bearing metal.

ISO 6526:2017 specifies the main features and tolerances for pressed bimetallic half thrust washers having an outside diameter up to 160 mm. NOTE 1 All the linear dimensions and tolerances are expressed in millimetres. NOTE 2 The main dimensions for the half thrust washers are not the subject of this document.