ISO/TS 31657-4:2020

ISO/TS 31657-4:2020 Overview

ISO/TS 31657-4:2020 is an International Standard providing technical specifications for hydrodynamic plain journal bearings, specifically focusing on multi-lobed and tilting pad journal bearings under steady-state conditions. This part of the ISO/TS 31657 series establishes permissible operational parameters, expressed as guide values, that are critical for safe and reliable calculation and performance assessment of these bearing types.

The key emphasis of this specification lies in ensuring operational safety by defining limits for lubricant film thickness, bearing clearance, load, and temperature during bearing operation. These empirical guide values are derived from geometrical, technological, and tribological considerations and serve as authoritative reference points for design engineers and maintenance professionals involved in bearing calculation and application.

Key Topics Covered

• Permissible Operational Parameters: The standard defines critical operational limits including minimum lubricant film thickness (h_min), maximum allowable temperature (T_lim), and maximum pressure (p_lim) that must not be exceeded to avoid bearing damage.

• Transition to Mixed Friction: Special attention is given to the transition phase from hydrodynamic lubrication to mixed friction, detailing acceptable sliding speeds (U) and lubricant film thickness values to prevent wear or damage during start-up and shut-down.

• Material Selection and Surface Conditions: Guidance is provided on material hardness differences and surface roughness to optimize running-in conditions and ensure durable bearing performance.

• Thermal and Mechanical Load Avoidance: The standard outlines temperature-dependent maximum pressures for different bearing materials, reflecting how thermal conditions influence bearing strength and lifespan.

• Bearing Clearance Optimization: Operational guide values for bearing clearance, profile factors, and gap ratios are included to improve guiding accuracy, cooling performance, and overall bearing stability.

• Lubrication and Filtration: The significance of lubricant cleanliness and appropriate oil filtration to maintain a sufficient lubricant film thickness in dynamic operation is emphasized.

Practical Applications

ISO/TS 31657-4:2020 serves as a vital resource for industries and engineers involved in:

• Design and Calculation of Bearings: Assisting mechanical and tribology engineers in selecting and calculating multi-lobed and tilting pad journal bearings that meet operational safety and efficiency criteria.

• Maintenance and Condition Monitoring: Offering parameters to evaluate bearing condition during start-up, shut-down, and steady operation, helping to anticipate wear and prevent failures.

• Lubrication System Design: Guiding lubricant type selection, filtration specifications, and circulation system design for optimal bearing performance and longevity.

• Material Engineering and Manufacturing: Informing choices related to bearing and journal material combinations, hardness differences, and finishing processes to enhance bearing running-in and reduce friction.

• Thermal Management: Enabling the development of bearing systems that effectively manage temperature rise, avoiding mechanical overloading and lubricant degradation under diverse operating conditions.

Related Standards

Professionals should consider ISO/TS 31657-4:2020 alongside related standards from the ISO/TS 31657 series and others that collectively guide plain bearing design and application, including:

• ISO/TS 31657-1: Calculation methodologies for multi-lobed and tilting-pad journal bearings.

• ISO/TS 31657-2: Calculation functions specifically for multi-lobed journal bearings.

• ISO/TS 31657-3: Calculation functions for tilting-pad journal bearings.

• ISO 4381, ISO 4382-1/2, and ISO 4383: Standards covering materials and multilayer constructions for plain bearings.

• VDI Richtlinie 2204: Recommendations related to bearing lubrication technology.

Integrating the operational guide values from ISO/TS 31657-4:2020 with these complementary standards ensures comprehensive understanding and control over bearing design parameters, enhancing system reliability and performance.

Keywords: ISO/TS 31657-4:2020, hydrodynamic plain journal bearings, multi-lobed journal bearings, tilting pad bearings, permissible operational parameters, bearing calculation, lubricant film thickness, bearing clearance, bearing temperature limits, tribology, bearing material selection, thermal management in bearings, bearing design standards, plain bearing lubrication.