Iso Tr 14179-2 Pdf High Quality May 2026
Understanding ISO/TR 14179-2: Thermal Load-Carrying Capacity of Gears
ISO/TR 14179-2:2001 is a technical report that provides a comprehensive framework for determining the thermal load-carrying capacity of industrial gear units. While structural strength often dictates gear design, the thermal limit—the power a gearbox can transmit without overheating—is equally critical to prevent lubricant degradation, scuffing, or component failure. Core Purpose and Scope
This technical report describes how to assess the thermal balance of a gear unit by calculating the equilibrium between generated power loss (heat) and heat dissipation to the environment. It is applicable to various gear types, including cylindrical, bevel, hypoid, and worm gears.
Unlike ISO/TR 14179-1, which focuses on a simplified analytical model for rating gear drives at a fixed 95 °C sump temperature, Part 2 offers a more detailed approach that includes measurements on original gear units under practical conditions. Key Methodology: The Thermal Balance
The document utilizes an iterative calculation method to determine the expected oil sump temperature for a given load, or conversely, the maximum power allowable for a specific temperature limit. 1. Power Loss Components
The report breaks down internal heat generation into several factors:
Gear Losses: Includes both load-dependent losses (related to tooth friction) and no-load (churning) losses. iso tr 14179-2 pdf
Bearing Losses: Calculations based on empirical data from bearing manufacturers' catalogs.
Seal and Auxiliary Losses: Heat generated by shaft seals and other rotating elements. 2. Heat Dissipation Paths It provides equations for how heat leaves the system:
Convection and Radiation: Heat transfer through the housing walls based on the Stefan-Boltzmann law and surface finish coefficients.
Conduction: Heat transferred through the foundation and connected shafts or couplings.
External Cooling: Assessment of requirements for oil coolers or injection lubrication systems. Practical Implementation
The methods described in ISO/TR 14179-2 were heavily influenced by research from the Technical University of Munich and the FVA (Forschungsvereinigung Antriebstechnik e.V.) in Germany. A widely used industrial software, WTplus, incorporates these exact calculation procedures for gearbox design. Where to Obtain the PDF Calculate the thermal rating of your existing gearbox
ISO/TR 14179-2:2001 is a copyrighted document and is typically not available for free legally. You can purchase the official PDF from several authorized distributors: ISO/TR 14179-2:2001 - Gears — Thermal capacity — Part 2
ISO/TR 14179-2:2001 provides standardized methods for calculating the thermal load-carrying capacity of gear units, balancing internal power losses against heat dissipation to determine maximum power transmission. The technical report covers both analytical calculations and practical measurement methods for gear, bearing, and seal losses to estimate oil sump temperatures. Official copies of the standard are available through organizations like ISO and DIN Media. ISO/TR 14179-2 - EVS standard evs.ee
ISO/TR 14179-2:2001 is a technical report titled "Gears — Thermal capacity — Part 2: Thermal load-carrying capacity". It provides analytical methods and practical measurement procedures to determine the amount of power a gear unit can transmit without exceeding specific temperature limits. Key Content & Purpose
The document focuses on the balance between power loss (heat generation) and heat dissipation to the environment.
Methodology: It combines theoretical considerations for individual loss components (gears, bearings, seals) with experimental investigations.
Thermal Balance: Includes equations for heat dissipation via natural and forced convection, radiation (based on the Stefan-Boltzmann law), and heat transfer through rotating parts or the foundation. and worm gears. Unlike ISO/TR 14179-1
Practical Measurement: Provides means for determining thermal capacity via measurement of power loss, heat dissipation, or quasi-stationary oil sump temperatures in splash-lubricated units.
Relationship to Part 1: While Part 1 focuses on rating gear drives at a fixed 95 °C equilibrium, Part 2 offers a more flexible analytical heat balance model and experimental alternatives. Accessing the PDF
As an international standard, the full text is typically behind a paywall. You can find official copies or technical previews at the following sites: ISO/TR 14179-2 | iTeh Standards
ISO TR 14179-2 vs. Other Gear Standards
Many beginners confuse this standard with others. Here is a quick comparison:
| Standard | Focus | What it Calculates | | :--- | :--- | :--- | | ISO 6336 (Parts 1-6) | Tooth bending and contact fatigue (pitting resistance) | Gear life in hours (mechanical strength) | | ISO TR 14179-1 | Scuffing (micro-welding) | Load limit before adhesive wear | | ISO TR 14179-2 | Thermal capacity | Maximum continuous power without overheating | | AGMA 925 A03 | Thermal rating (American standard) | Similar to ISO TR 14179-2 but with different constants |
If you only calculate mechanical strength (ISO 6336) but ignore thermal capacity, your gearbox may be mechanically sound but will burn up in the first hour of continuous use.
7. The "So What?" for a PDF Download
If you pull the ISO TR 14179-2 PDF right now, here’s what you can do in 60 minutes:
- Calculate the thermal rating of your existing gearbox – you’ll likely find it’s 15-30% lower than the mechanical rating.
- Identify whether adding cooling fins, a fan, or a different paint color gives the best ROI.
- Avoid adding an expensive external oil cooler when simply increasing housing surface area (using the report’s "rib efficiency factor") would solve the problem.
A. Determination of Power Losses ($P_V$)
The document breaks down efficiency losses with granular detail:
- Gear Mesh Losses ($P_VZ$): It provides formulae for calculating friction coefficients based on sliding and rolling action. It accounts for the influence of gear geometry (involute contact ratio) and lubrication regimes.
- Bearing Losses ($P_VL$): It includes methods for estimating frictional torque in rolling element bearings, heavily referencing ISO 281 and bearing manufacturer data.
- Seal Losses ($P_VD$): Though typically minor, the document accounts for friction at shaft seals.
- Auxiliary Losses: It discusses losses from oil pumps or other internal components.
